1. Introduction to iOS 11, Xcode 9 and Swift 4.srt

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Stanford University. >> Okay, well welcome then,
斯坦福大学 >> 欢迎参加

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to Stanford CS193P. This is Developing Applications for
斯坦福 CS193P，iOS 应用程序开发

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iOS. Hopefully you're in the right place.
希望你们走对了教室

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This is fall quarter of 2017. And I'm gonna breeze through
现在是 2017 年秋季学期。我先简单

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a few slides here. And then I'm gonna sit down and
讲几页幻灯片，然后坐下来

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do a nice involved demo just to show you what it's like
给你们写个程序演示一下

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developing apps for iOS. That's the best way to learn,
开发 iOS 程序是什么样的。这是最好的学习方法

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it's for me to show you how to do it. So
让我来给你展示怎么做

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this will be what I'm gonna talk about briefly first.
现在我先简单讲讲

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So what are you gonna learn in this course?
你在这节课会学到什么？

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Of course you're gonna learn how to build cool apps.
当然你会学习如何编写很酷的程序

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iOS apps are cool. Why are they cool?
iOS 程序都很酷，为什么呢？

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Well, they're cool because they live in your pocket, you
因为他们“活”在你的口袋里（的手机上）

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can show them to your friends right there, also incredibly
你随时可以展示给你的朋友们看

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easy to sell and market your apps online because you have
同时还能很轻松地在在线商店销售，因为

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the App Store. And there's a very vibrant community that's
有 App Store。那可是个很活跃的大平台

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because Apple is always doing cool new things like virtual
因为苹果公司总是在做很酷的事情

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reality and machine learning and all these things.
比如今年的虚拟（增强）现实和机器学习

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And there are millions of apps on the app store, so there's
同时 App Store 里有成千上万的程序

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a lot of people doing this stuff. But you're also gonna
很多人都在做 iOS 开发。同时你会

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learn in this class a little bit of real life
在这节课中学习到实际运用

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Object-Oriented Programming.
面向对象编程

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You all are taking classes, networking and databases and
你在其他计算机课程中学习到了网络，数据库

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graphics, your other CS classes. And here we're gonna
图形等，在这里你将会

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do all those things in a real life platform.
在 iOS 平台上实际运用这些

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Because over the weeks we are going to do all of those
因为这几周的时间我们会

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computer science things for real. And especially
实际运用这些计算机相关的知识

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Object-Oriented Programming, cuz iOS is completely and
特别是面向对象编程，因为 iOS

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utterly object-oriented. You cannot develop for
是完全面向对象的。除非你掌握了面向对象编程

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iOS without being serious object oriented programmer.
否则你不可能开发 iOS 程序

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And that brings me to my prerequisite for this course,
正好我可以讲讲上这门课的前提

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which is Object-Oriented Programming. You have to be
其中之一是面向对象编程

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comfortable with Object-Oriented Programming.
你必须要适应面向对象编程

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Definitely CS106 A and B and hopefully CS108,
必须要上了 CS106 A/B，最好是 CS108

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which is Object-Oriented Programming here at
这些是斯坦福开设的面向对象编程课程

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Stanford. And the other thing you gotta to be comfortable
其他你需要能适应的是

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with is writing a lot of code. All your homework in this
写很多代码。这节课所有的作业

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class, there's a little bit of reading the first few weeks
前几周还会有些关于我们

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about the language that we're gonna develop in.
开发要用的语言的阅读作业

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But mostly it's just programming, programming and
但其他的大部分都是写程序，写程序

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more programming. So if you're not comfortable writing a lot
写更多的程序。所以如果你不能适应天天敲代码

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of code then this class, you might wanna wait until
那你应该等等再上这节课

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you've taken some other classes that ask you to
你可以先上其他要写很多代码的课

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write a lot of code before you dive in here.
然后再来上这节课

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So what's in iOS? What am I gonna be teaching you?
好，那么 iOS 里面都有些什么？我要教你什么？

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I've divided it here into four layers.
我们可以把 iOS 分成四层

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The bottom layer is near the hardware, and
最下面的一层最接近硬件

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the top layer is near the user. So at that bottom layer,
最上面一层最接近用户。所以最底下的一层

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you might be surprised to find out that iOS is Unix.
你会很惊奇的发现 iOS 其实是 Unix 系统

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It's a BSD variant of Unix. And so all of the stuff
BSD 版本的 Unix。所以所有的这些

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that's going on down there is all happening in C basically.
在这里运行的程序大多都是用 C 语言编写的

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Unix is mostly written in C, most of that stuff is in C.
Unix 几乎是用 C 语言写的，大部分都是

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I'm not gonna teach you anything at this layer.
我不会教你这个层面的内容

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This is an object-oriented class,
这节课是教面向对象的

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everything we do will be object-oriented.
我们要写的程序也都是面向对象的

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You will not see me teaching you anything down there,
你不会看到我教你这部分的内容

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The next layer up is called the Core Services layer.
在那一层之上是 Core Services 层

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all right?
是吧？

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This is an object-oriented layer on top of those lower
这一层是对下面那层服务的面向对象封装

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services. This I will be teaching you. So if we wanna
我会教你这一层的内容。如果我们想要

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do things like find out where the phone is on the planet or
做比如这个手机在地球上的什么位置

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find out its orientation or access some files in the file
或者设备的方向，或者访问文件系统

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system, we're gonna be using this layer right here and I'll
我们就需要用到这层，我会

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be teaching you all about this layer. Core Services layer.
教你使用这一层，Core Services 层所有的功能

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The next layer up, this is kind of not a strict layering,
再上面一层，这不是很严谨的分层

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but is the Media layer. Don't forget that your iPhone
但这层是媒体（Media）处理层，不要忘了你的 iPhone

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is essentially, originally an iPod with a phone in it. So
原本是可以打电话的 iPod

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it's got all kinds of media, video, audio,
所以它能够对各种媒体，比如视频，音频

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many different kinds, images, all this stuff. And
以及众多格式的图片等进行处理

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unfortunately this is a layer I'd love to teach you but
虽然我很想教你们这些内容，但不幸的是

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I have to cut something, so I'm not gonna talk much about
我必须要消减一些内容，所以我不会讲太多

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this layer, unfortunately. So I know some of you might be
这层的内容，真的很不幸。我知道你们中的有些人

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wanting to write a cool game that has 3D sound with TIE
会想要编很酷的程序，有 3D 环绕声伴随

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fighters ripping around from the back of you to the front.
（星球大战里的）钛战机从后面飞到前面

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And that's all possible, and quite straightforward to do,
这些都是可能的，而且实现很简单

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but in ten weeks I have to pick what I'm gonna teach you,
但是我必须要选择十周的时间我应该教你们什么

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and so I'm gonna focus on Core Services. And then this layer,
所以我会更加注重 Core Services 层的内容。最后一层

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which is Cocoa Touch. So Cocoa Touch is the UI layer of iOS.
也就是 Cocoa Touch 层，它负责 iOS 的用户界面

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This is where the buttons and
这一层是比如按钮

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the sliders, all those things are in. And
滑杆（Slider）等控件定义的地方

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there's also, really powerful objects here, like the MapKit
这一层还有其他强大的对象，比如 MapKit

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has a single object that you can just drop in your app
有个对象，你可以直接把它加到程序里

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that gives you pretty much the entire functionality of
然后你就有了整个

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the map's app inside a rectangle, inside your window.
地图程序的功能，呈现在窗口里的某个矩形里

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So, you're talking about a wide variety of UI stuff here
所以你会遇到各种 UI 控件

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and I'm gonna try and cover as much of this as I can. So
我会尽量多地讲解这一层的内容

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that's what you're gonna learn in this class.
这就是你会在这节课中学习到的内容

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The platform we're gonna develop on is Xcode 9, so
我们的开发平台是 Xcode 9

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you're all gonna need to download Xcode 9,
你需要从 Mac App Store 免费下载 Xcode 9

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it's free and it only runs on your Mac.
（千万别从百度云等第三方下载）注意只支持 Mac

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And, there's this other little app, Instruments, but it's
同时还有一个程序，Instruments

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really kind of just an add-on to Xcode 9. We're gonna do
Xcode 附带的程序，更像是插件。我们会

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everything in Xcode 9, source code, editing, debugging,
在 Xcode 9 中做所有的事情，写代码，编辑，调试

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all that stuff is gonna happen in Xcode 9. You're also gonna
这些都是在 Xcode 9 中完成。你同时还要

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have to learn a new language. iOS has two languages you can
学习一门新的语言。开发 iOS 有两种语言可以选择

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develop in, Objective-C and Swift.
一个是 Objective-C，一个是 Swift

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Swift is the newer one, that's the one I'm gonna teach you.
Swift 是更新的一个，同时也是我会教你的语言

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Everything you learn though in Swift, all about iOS,
所有你用 Swift 学到的关于 iOS 的知识

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will apply if you later wanna go learn Objective-C and
如果你之后决定学 Objective-C 都是可以用到的

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work for a company that is still writing in Objective-C,
也可以用在还在使用 Objective-C 的公司的程序里

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which is perfectly valid language to write in.
因为 Objective-C 也是可以独当一面的语言

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But Swift kind of a cool new language,
但是 Swift 是更潮的新语言

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I think you're really, really gonna like it.
我相信你会喜欢上它的

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If you're a serious Computer Scientist another language is
如果你是个认真的程序员的话，学习一门新语言

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like big yawn whatever. Just tell me what the syntax is,
你听了应该觉得这很简单，你告诉我语法

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tell me what they key fundamental mechanisms for
告诉我那些基本的，关键的

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designing with it are, and I'll learn it.
程序设计方法，然后我就去把它掌握了

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So, if you don't have that attitude towards languages,
如果你不能这样接受学习新语言

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you're gonna be kind of having trouble out in the real world
你在现实生活中就会有麻烦了

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being a programmer. And then of course,
不容易当好程序员。当然

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there's millions of what we call Frameworks in iOS.
iOS 里有很多被称为框架（Frameworks）的东西

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Frameworks are just collections of objects.
框架就是对象的集合

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Like the biggest one is UIKit, that's where buttons, and
最大的一个是 UIKit，里面有按钮

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sliders, and all that stuff is. Foundation is another
滑杆等那些控件。Foundation 框架

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big one. That's where a lot of that core services stuff I was
也不小，里面主要是 Core Services 层的内容

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talking about is. But there's the MapKit, Core Motion,
但同时还有 MapKit、Core Motion

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Core Data, Object Orient, Database, all kinds of them.
Core Data（面向对象数据库）等等框架

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And I'll try and get to as many of them as I can. And
我会尝试讲到尽量多的框架

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last but definitely not least, there is a Design Strategy for
最后一个，同样重要的，设计模式

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building iOS apps that you have to use.
用来开发 iOS 程序必须要用的

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This is not like an optional, here's a good idea, why don't
这并不是一个选项，或者某个很好的点子

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you design this way? You must design this way. It's called
建议你这样设计。不，你必须这样设计。它叫做

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MVC, Model View Controller. How many people have,
MVC，即 Model（模型）-View（视图）-Controller（控制器）

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some experience doing MVC in any other? Okay, it's not so
这里有多少人有使用过 MVC？好吧

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many this quarter. Usually I get half the people but
这学期没有那么多人。通常会有一半的人

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I'll be teaching all about MVC.
但我会教你们 MVC

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The start of lecture on Wednesday is gonna be a full
星期三一开始会详尽地

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coverage of MVC. What it is, how it works, all that stuff,
讲 MVC，包括它是什么，怎么工作的，等等

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all right? So now, I'm gonna dive right into a big demo
好吧？现在，我会开始一个大型的示例程序

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that's the best way to learn how to do iOS development is
最好的学习 iOS 开发的方法

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with a demo. Seeing it happen, we're gonna build
就是看实例。看着如何做的，我们会

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an application from scratch. This slide right here,
从头开始写一个程序。这页幻灯片

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is a slide for you to look at later, and
是给你们之后看的

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see, did I learn all these things, because I should have
对照检查下我是否学会了这些，因为我

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learned them today. This is not a slide to read now.
在今天的课上学了。你们不用现在看

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Since I'm not gonna get back to the slides,
因为我不会再回到幻灯片

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let me just say what's coming up real quick. You are gonna
我快速地讲讲之后的安排

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have a reading assignment that goes out today.
我今天会布置给你们阅读作业

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It's basically starting to read the manual on
要求基本就是开始阅读 Swift 的说明书

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Swift. So you can learn this new language. It'll be all
以此来学习这门新语言

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spreaded out over three maybe four weeks, so you don't have
我会给你们大概三到四周读完整本书

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too much reading all at once. But
我不会一次要求你读太多

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those reading assignments are gonna be in addition to
但是不止是阅读作业

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programming assignments. The reading assignments are going
你们还会有编程作业。阅读作业是周一布置

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to go out on Monday, they come back on Monday,
下周一交

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they're due the next Monday. And
阅读作业是下周一交

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then the program assignments go out on Wednesday and
编程作业是星期三布置

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then they're due the next Wednesday generally.
一般来说会是下周三交

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Okay, at least we'll start the quarter that way.
好，至少我们一开始是这样安排的

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On Friday, we have an optional section,
星期五的课是选修课

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it means optional that you don't have to go there.
你可上可不上

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The topics we're gonna cover are kind of additional, but
讲的主题也会是额外的内容

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this Friday is one is a big one, it's tips and
但这周五的很重要，是关于

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tricks of Xcode, including how to use the debugger.
Xcode 使用的提示和技巧，包括如何使用调试器

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So if you've never used the debugger in Xcode,
如果你从没有使用过 Xcode 的调试器

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this is a good one to go to, so
我推荐你来参加

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you can see how to use the debugger for your problem.
你能见识到如何用调试器解决问题

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If not, you know, it's a debugger, if you used other
如果你不想来的话，嘛，就是个调试器，如果用过了其他的

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debuggers, you could probably figure it out, but anyway, it
调试器的话，你应该能够自己琢磨出来

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says right there that it's in Hewlett 205, but I don't think
这里写着会在 Hewlett 205，但我并不觉得

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there's such a room. I think it might be in Hewlett 105.
有这么个教室。我认为应该在 Hewlett 105

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I don't know, watch Piazza and we'll tell you where it is.
我记不清了，注意看 Piazza 上我告诉你们的地址

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But it is gonna be 11:30 to 12:20. And so next week we'll
但时间是 11:30 到 12:20。下一周

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talk more about Swift and then launch into all of iOS,
我们会更多的讲 Swift，然后就完全是 iOS 了

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all right? So let's jump right into the demo here.
好吧？我现在就开始演示写程序

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And I apologize in advance for going fast on this demo,
我这里提前道歉，这个演示我会过得很快

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because we have a lot to cover, and
因为我们要讲的实在是太多了

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you're gonna find that in this course, in general,
而对于这门课来说，你会发现这是普遍现象

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I tend to go pretty quick, cuz I wanna teach you as much of
我一般讲得很快，因为我想要教你们更多的内容

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this stuff as I possibly can. All right,
能教多少教多少。好

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Xcode. Here's Xcode. I went to the Mac App Store.
打开 Xcode。这就是 Xcode，去 Mac App Store

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I searched Xcode, I found it. I downloaded it.
搜索 Xcode，找到并下载

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It was free, it doesn't cost me a dime to develop for
Xcode 是免费的，不用花一分钱就可以开发

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iOS. When you launch Xcode for the first time,
iOS 程序。当你打开 Xcode 的时候

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you're gonna get this thing right here. So
你就会看到这个欢迎界面

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we need to build an app. Now, I decided to show you the app
我们需要构建一个程序。我准备先给你们展示

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that I'm gonna build here in real life. So you see these
我这个程序在现实生活中是怎么玩的。你看到这些

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cards that I've very artfully taped up here? These cards
卡片，就是我粘在这里的这些？这些卡片

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are going to let me play a game called Concentration.
可以用来玩一个叫做翻牌（Concentration）的游戏

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How many people have heard of the game Concentration?
有多少人听说过翻牌这个游戏？

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Not too many. Okay, so Concentration is just a card
不是很多。好吧，翻牌这个游戏就是个卡牌游戏

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game. Behind these cards that are all face down,
这些正面朝下的卡片上

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there are some pictures, and the goal is for
都有某张图片，我们的目标是

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you to match the pictures up. So there's 12 cards,
找到相同的图片。这里有 12 张卡

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6 pairs of pictures, so I get to pick two cards at a time,
6 对图片。所以我一次挑选两张

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and if they match, I win, and
如果是相同的，我就赢了，然后

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the cards go away. If they don't match,
牌放一边。如果不一样

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I have to turn them back down and pick two other cards, and
我就需要把它们放回原处，然后重新选两张

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it's called Concentration cuz I have to concentrate on
这个游戏叫做 Concentration 是因为要集中注意力

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the ones that didn't match, so that later I can go back and
关注那些没有配对上的，然后之后来

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match them. So, let's just flip some cards over here.
配对。让我们翻开这里的某些卡片

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I'm gonna start with this one right here.
我先从这个开始

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I really don't know what's behind there, but let's see.
我并不知道后面印的是什么图案

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Okay, this one is a pair of purple bats.
好，这个是一对紫色的蝙蝠

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So now I'm trying to find another pair of purple bats,
我们需要找到另一对紫色蝙蝠

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let's try right here. I found them right away, okay.
让我们试试这里的这个。啊，马上就找到了

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So this is a match, I get some points.
所以这是相匹配的，我就得分了

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These come off the board. So now I'm searching for
然后就拿下来。现在我要找到更多能配对的

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more matches. All right, let's try this one right here. It's
让我们来试试这里的这个

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a ghost. I got the ghost right there. Let's try this one.
这是个鬼。我这里有个鬼，让我试试这个

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No, no match. That looks like a Rorschach thing, but
啊，不一样，那看起来像罗夏墨迹测验

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it's a witch. Turns out that's a witch on her broom,
但其实是女巫，骑着扫把的女巫

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if you can see right there. So, I don't get any points for
如果你能看到的话。所以我没有得分

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this and I have to turn these back down and pick two other
然后需要放回去，然后另选两张

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cards. All right, so I'll turn these down.
好，让我们翻回去

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Hopefully you guys are concentrating, and
希望你们注意了

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you can remember what these things are. I'm gonna try this
然后能记住这些都在哪里。让我试试这个

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one. It's a cat, kind of a cute cat right there, and
是只猫，可爱的猫

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let's pick another one, how about this one. A pumpkin!
让我们再选另外一张，这个怎样？是个南瓜！

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Okay, well, in some ways, this is bad,
某种意义上说，这很不好

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because we have another non match,
因为我们又没有配上对

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but it's kind of good in that supposedly,
但同时也有好处

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if we we're concentrating we know where four cards are. So
如果我们注意了，我们就知道这四张卡在哪里

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turn these back down. Pick two new ones, and
然后我们又翻回去。选两张新卡

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I'm gonna pick cards that I haven't seen before,
我要挑还没有翻过的卡片

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because I already know where these cards are.
因为我已经知道这些是什么了

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All right, that doesn't fall down.
好，这个没掉下来

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All right, how about this one. This one is, The witch,
让我们选这个。这个是女巫

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the witch! Okay, so now if I was concentrating,
女巫！如果我注意了的话

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I remember where the witch was, now where was it? Was it,
我会记得另一个女巫在哪里，在哪里呢？

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I think, was it this one? Yeah? Witch, yes, okay!
我觉得是这个？是的！另一个女巫！

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So we match these, and these come off the board, and this
我们找到了配对的，就把这对拿开

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just continues, and obviously the fewer things you choose,
然后继续重复。显然你应该尽量少挑选

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okay, the fewer times that you pick, like here is a cat.
你应该尽量减少挑选的次数。比如这是个猫

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Where's that cat? I think it's down here.
另一只在哪里？我记得在下面这里

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No, that's not a cat. Now this kind of a mismatch
不，那不是一只猫。像这种没配对的

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I should be probably get a big penalty for,
我应该得到严重的处罚

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because the cat I've seen before, it's right here.
因为我之前看到猫就在这里

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So I should have matched it, and I didn't,
我应该是能配对的，但是我并没有

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I wasn't concentrating. So this is the game we're gonna
因为我注意力并没有集中，所以这就是我们要

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build an app to do. All right, make sense? Simple game.
编的游戏。这个游戏简单吧？

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All right back to Xcode right here. Now this Xcode portal,
我们回到 Xcode。这个 Xcode 的首页

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the splash screen that pops up here.
显示的是这个启动页

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It has all the apps that you've been working on all
右边这里会显示这学期你所有的程序

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quarter. Right here, and then it lets you create a new app
就在这里。你还可以新建一个程序

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over here where it says create a new Xcode project. So,
在写着 Create a new Xcode project 这里

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we're gonna create a new Xcode project.
我们要新建一个 Xcode 项目

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I just click that button. When you create a project,
于是我们点这个按钮。当你新建一个项目的时候

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it asks you what kind of project do you wanna build?
它会问你是什么样的项目？

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And we wanna build an iOS app, you see up here at the top.
我们要编的是 iOS 程序，就是最上面这里选的

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We could build a watch app, or an Apple TV app,
我们还可以编写 Apple Watch，Apple TV 程序等

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but we're building an iOS app, and
但我们这节课是编写 iOS 程序

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this is saying what kind of iOS app would you like?
接着又问你是什么样的 iOS 程序？

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So here's a game, augmented reality. We're always gonna
可以是 Game（游戏），Augmented Reality（增强现实）

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pick this one in the upper left corner, single view app,
但我们要选的是左上角这个，Single View App

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because it's the simplest starting template, and I wanna
因为单一视图程序是最简单的模版

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teach you how to write the code to do all those
我会教你如何编写其他的这些模版

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other ones. I don't want you just click a template, and
我不希望你只是点击一个模版

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it just shows you the infrastructure for a game, or
然后就有了整个游戏的基础结构

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whatever. I wanna show you how to do that.
或者其他什么的；我想要教你如何实现那些

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So we're always gonna pick single view app.
所以我们总是选 Single View App

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When we pick the kind of app we want it's gonna ask us some
当我们选了程序的类型之后，Xcode 会问

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questions like what do you wanna call this app?
你想要把这个程序叫做什么

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00:12:21,207 --> 00:12:24,676
Well this game is called Concentration, so I'm gonna
这个游戏叫做 Concentration，我就叫

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say Concentration. The next one down here is Team.
这个程序 Concentration。下一个是 Team

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That's the development team working on it. That's you. Now
这个是你工作的开发团队，也就是你自己

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when you are on it it's gonna say Add Team or Make Team right
你的 Xcode 会显示 Add Team 或是 Make Team

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00:12:35,088 --> 00:12:38,723
there. To me, it knows it's me, and when you do that,
但是我的 Xcode 已经知道我是谁了。对你而言

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all you're gonna need to create a development team is
要创建一个开发团队，你只需要

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an Apple ID. You don't have to pay any money.
一个 Apple ID。这不需要交钱

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Any Apple ID will do, go through the process.
任何 Apple ID 都可以，跟着步骤走

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You'll create a development team. Next,
创建了开发团队之后

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is this Organization Name. That can be anything you want.
是 Organization Name。这组织名称随便填

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It just shows up in the copyright in your Swift files,
它会显示在 Swift 文件的版权声明里

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all right? But this one, very important that this be
但 Organization Identifier 很重要

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uniquely identifying you. So a real easy way to
这个是你独一无二的标识符。最简单的方法

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do that if you're a Stanford student is
如果你是个斯坦福的学生，就用

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edu.stanford.cs193p, your SUNet id.
edu.stanford.cs193p.你的SUNetID

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Instead of lecture there, put your SUNet ID.
不填 lecture，而是你的 SUNet ID

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That's clearly gonna identify you. If you're not a Stanford
那就可以识别出是你了。如果你不是斯坦福

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student, you have to figure it out on your own, and
学生，那你需要自己想一个（惯例是网站域名的反写）

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then the language I told you about, the two languages,
最后 Language，我之前说的那两个

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we're gonna do all our development in Swift. You can
我们的开发全部会用 Swift。你还可以

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mix Swift and Objective-C even in the same application.
在同一个程序里混用 Swift 和 Objective-C

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They're very interoperable. Swift was designed fully with
它们是能协同工作的。在设计 Swift 时候充分

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Objective-C in mind, so it's not a problem. So we'll always
考虑了 Objective-C，所以这不会是个问题。所以我们总是

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pick Swift here, and we're not gonna do any of these
在这里选择 Swift 语言。我们不会用到

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things down here in the first two weeks,
下面的这些，至少前两周不会

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00:13:34,881 --> 00:13:37,648
but we will eventually get it, object-oriented databases, and
但我们最终会讲到面向对象数据库

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00:13:37,717 --> 00:13:39,717
testing, we'll eventually do that stuff.
和测试这些，都是会讲的

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So I'm gonna click next.
接着点 Next

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Now it's asking me where do you wanna store your project?
现在问我要把项目放在哪里

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I strongly recommend you put it in your home directory,
我建议放在你的用户根目录下的

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00:13:46,492 --> 00:13:49,693
in a folder called Developer, that's the kind of a canonical
Developer 文件夹里（~/Developer）。这像是个钦定的

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00:13:49,762 --> 00:13:51,728
place that people put their projects.
人们经常放他们项目的地方

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All your projects will collect here, okay, concentration, and
你所有的项目都会在这里，今天是 Concentration

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00:13:55,101 --> 00:13:57,368
then the other ones we're gonna do later in the quarter.
然后是这学期之后的项目

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00:13:58,304 --> 00:13:59,537
This source control,
这个 source control

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00:13:59,605 --> 00:14:02,774
we'll talk about that later in the quarter as well, but
源码（版本）管理我们也会在之后讨论，但是

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00:14:02,842 --> 00:14:06,477
we're not doing that for the first week. Okay here it is,
我们在第一周不会做这件事

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00:14:06,546 --> 00:14:10,381
your first iOS app. Now what we're seeing in the middle of
这里是你的第一个 iOS 应用。现在你正在看 Xcode 的中间

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00:14:10,450 --> 00:14:13,150
Xcode, how many people have done something in Xcode
有多少人之前用 Xcode 做过一些东西

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00:14:13,219 --> 00:14:15,787
before? Okay, so about half of you, so that's pretty common.
好吧，大约有一半的人，这是很常见的

295
00:14:15,855 --> 00:14:19,123
So you know that in Xcode, this middle area is your main
所以你知道在 Xcode 中，中间的部分是你的主要编辑器

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00:14:19,192 --> 00:14:22,026
editor, and right, we're seeing right now,
右边你正看到的

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00:14:22,095 --> 00:14:24,796
in this main area, is our project settings.
在这个主要区域里，是我们的项目设置

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00:14:24,864 --> 00:14:28,099
We answered some of these in those previous little things
我们之前回答了它们中的一小部分的功能

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00:14:28,168 --> 00:14:31,235
that came up, and the reason it's showing our project
它之所以显示我们的项目设置

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00:14:31,304 --> 00:14:34,238
settings is because on the left here in this blue area
是因为在左侧的蓝色区域

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00:14:34,307 --> 00:14:37,708
we have the project selected, see the dark blue selection at
我们选中了项目，就是在上方的深蓝色选中的部分

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00:14:37,777 --> 00:14:40,377
the top. That's the project selected, and
那就是我们选中的项目

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00:14:40,446 --> 00:14:43,714
this whole blue area on the left is called the navigator,
左侧这整片蓝色区域叫做导航栏（navigator)

304
00:14:43,782 --> 00:14:47,117
and the navigator let you navigate through your project,
导航栏让你巡览整个项目

305
00:14:47,186 --> 00:14:50,321
and in this particular tab it's showing me the files in
这个选项卡展示了我的项目中的文件

306
00:14:50,390 --> 00:14:52,689
my project. I have six files right here,
我一共有六个文件

307
00:14:52,758 --> 00:14:56,561
they were given to me when I chose that template, the single
当我选择这个模板我就有了它们

308
00:14:56,629 --> 00:14:59,796
view template, but I can also now navigate by searching,
即单视图模板，但是我仍能通过搜索导航

309
00:14:59,865 --> 00:15:02,967
right here. If I'm debugging I can navigate through my break
如果我想调试，我可以巡览我的断点

310
00:15:03,035 --> 00:15:06,370
points, etc. So you'll get real familiar with using this
所以你将马上熟悉

311
00:15:06,438 --> 00:15:07,772
blue thing right here,
使用这个蓝色区域

312
00:15:07,841 --> 00:15:10,641
and you can say how much space you want it to have to
你还能决定你需要多大的空间来导航

313
00:15:10,709 --> 00:15:12,911
navigate through your application.
你的应用

314
00:15:12,979 --> 00:15:15,379
Now on the right hand side, this over here,
在右手边的区域

315
00:15:15,448 --> 00:15:18,215
you can actually see a little area that has a top and
你可以看到一个有上方和底部的

316
00:15:18,284 --> 00:15:22,153
a bottom. This is called the utilities pane, and
小区域，它叫做 Utilities pane (工具栏)

317
00:15:22,221 --> 00:15:25,155
I'm gonna show you all about that in five minutes.
我会在五分钟内展示它的所有

318
00:15:25,224 --> 00:15:26,424
So I'm gonna hide it right now.
现在我会先把它隐藏起来

319
00:15:26,492 --> 00:15:28,926
You see this button in the very upper right.
你可以看到在最右边的这个按钮

320
00:15:28,995 --> 00:15:33,197
That hides that, and this one hides the navigator. So if you
它隐藏工具区域，这个隐藏导航栏

321
00:15:33,266 --> 00:15:36,334
wanna give more space to your main window, you can do that.
如果你想要给你的主要窗口更多空间，你可以这样做

322
00:15:36,403 --> 00:15:38,469
There's another button here, you see that one?
这里有另一个按钮，你看到了么？

323
00:15:38,537 --> 00:15:41,405
That hides your debugger and console window.
它隐藏你的 debugger（调试器）和 console（控制台）窗口

324
00:15:41,474 --> 00:15:44,041
So this is the debugger right here where you're looking, I
这个就是调试器

325
00:15:44,110 --> 00:15:46,644
think, going on your debugger, and this is the console.
这个是控制台

326
00:15:46,712 --> 00:15:49,414
Now, the console is just a place where there's a function
在控制台，我们可以打印

327
00:15:49,482 --> 00:15:51,482
in Swift where we can print text out there.
一个 Swift 函数的文本

328
00:15:51,550 --> 00:15:53,350
It's really great for lightweight debugging.
它是非常好的轻量调试的方式

329
00:15:53,419 --> 00:15:56,053
We're just printing out what's going on. Inside my app.
我们就是打印出应用里正在进行的东西

330
00:15:56,122 --> 00:15:57,021
And that's what I'm going to do today,
这就是我今天要做的事情

331
00:15:57,089 --> 00:15:58,989
I'm not going to show you the debugger today, that's for
今天我不会给你们展示调试器

332
00:15:59,058 --> 00:16:02,159
Friday. I'm just going to show you using print to debug and
那是周五做的。我仅仅要展示使用打印来调试

333
00:16:02,228 --> 00:16:05,128
you can also move this up and down as high as you want. So,
并且你可以上下移动它来调整高度

334
00:16:05,197 --> 00:16:07,398
it's very nice to be able to, kind of, organize your space.
所以它对于组织你的空间十分友好

335
00:16:07,467 --> 00:16:10,100
I have a fairly low resolution screen here. So
我有一个比较低分辨率的屏幕

336
00:16:10,169 --> 00:16:12,703
I'm going to be trying to hide things as much as possible to
所以我会尽可能隐藏一些东西

337
00:16:12,771 --> 00:16:16,607
make the text really big so you can see what I'm doing.
来让文本尽可能大到让你看见我在做的事情

338
00:16:16,676 --> 00:16:19,777
All right, one last thing I want to show before we dive in
好了，在进入演示程序之前我想展示最后一件东西

339
00:16:19,846 --> 00:16:22,980
here, is this area up here, you see this, this is how you
是这个区域，你能看到的，是你如何运行你的应用

340
00:16:23,049 --> 00:16:27,318
run your application. Okay so, when you run your application,
当你运行你的应用时

341
00:16:27,387 --> 00:16:30,755
you have to decide where are you gonna run it. You can run
你必须决定你要在哪里运行它

342
00:16:30,823 --> 00:16:34,325
it on a device, so you can hook up a device to your Mac.
你可以在一台设备上运行，所以你必须将设备与 Mac 连接起来

343
00:16:34,393 --> 00:16:36,427
And you can hook it up wirelessly actually or
事实上你可以无线连接或者

344
00:16:36,495 --> 00:16:39,696
with a little USB cable or whatever. And I don't have any
用一根 USB 线或其他方法。我这里

345
00:16:39,765 --> 00:16:43,100
hooked up, so I can't do that. But I can also can run on all
没有可以连接的东西，所以我不能这么做。但是我仍可以在所有的

346
00:16:43,168 --> 00:16:47,405
of these simulators. So, these simulators simulate these
simulators（模拟器）中运行。这些模拟器模拟各式的设备

347
00:16:47,473 --> 00:16:52,176
various device like an iPad or iPhone 8+ or whatever. And
像 iPad，iPhone 8 Plus 以及其他设备

348
00:16:52,245 --> 00:16:54,311
you can run your app on any of these that you want and
你可以在任意模拟器上运行你的应用

349
00:16:54,380 --> 00:16:56,547
in fact, the simulator will open both of these,
事实上，模拟器可以在同一时间打开两个

350
00:16:56,616 --> 00:16:59,616
multiple of these as a time, if you want. So I'm gonna
或者多个，如果你想的话

351
00:16:59,685 --> 00:17:02,820
do the latest and greatest here which is the iPhone X.
所以我会用最新也是最好的模拟器，即 iPhone X

352
00:17:02,889 --> 00:17:05,189
Okay I'm gonna run my app on IPhone X and
好的，我会在 iPhone X 上运行我的应用

353
00:17:05,258 --> 00:17:07,791
let's go ahead and run it. We haven't done anything, so
让我们直接运行它。我们还没有做任何事情

354
00:17:07,860 --> 00:17:09,660
it's just a blank app and let's just run it for fun.
所以它仅是一个空白的应用，但我们还是运行它看看

355
00:17:09,729 --> 00:17:12,496
You see this play button right here? That's how you run, so
你看到那个播放按钮了么？那就是你运行它的按钮

356
00:17:12,564 --> 00:17:15,499
I'm gonna click that play button. Now it is compiling my
我会按下那个按钮，现在它正在编译

357
00:17:15,568 --> 00:17:18,169
app as you can see at the top, it's it building into
我的应用，正如你在上方看到的，它正在被编译成一个

358
00:17:18,237 --> 00:17:21,371
a binary. It's loading it onto the device, or
二进制文件。它正在加载到设备中

359
00:17:21,440 --> 00:17:24,742
in this case, simulator. And it runs it. Okay so
在这个情况下，是模拟器。然后运行它

360
00:17:24,811 --> 00:17:27,011
here it is. It looks like an iPhone X and
它就在这里了。它看起来是一台 iPhone X

361
00:17:27,080 --> 00:17:28,979
it's running my app and it's completely blank.
正在运行我的应用，它看起来是完全空白的

362
00:17:29,048 --> 00:17:30,314
Well because I haven't done anything,
因为我还没有做任何事情

363
00:17:30,383 --> 00:17:34,218
I haven't built any UI. But if I press the home button
我还没有构建 UI，但是如果我按下 home 键

364
00:17:34,287 --> 00:17:37,321
on the iPhone X, everyone know how that works? You slide up
在 iPhone X 上，每个人都知道它如何工作么？你从底部

365
00:17:37,389 --> 00:17:40,057
from the bottom. Sliding up from the bottom is like
向上滑动。从底部向上滑动就像

366
00:17:40,126 --> 00:17:43,460
the home button because there is no home button in iPhone X.
home 键的功能一样，因为在 iPhone X 上并没有 home 键

367
00:17:43,529 --> 00:17:45,896
And you can see there's our app concentration right there.
你能在那里看到我们的应用 翻牌

368
00:17:45,965 --> 00:17:47,297
But all other apps are there too.
其他的应用也都在那里

369
00:17:47,366 --> 00:17:50,434
Settings, right, you can go into the settings app. And
设置，如果你想的话

370
00:17:50,503 --> 00:17:53,337
if you want, you might have your app needs to set some
你可以进入设置应用，你的应用可能需要一些

371
00:17:53,406 --> 00:17:57,107
setting like, I don't know, text size or something like that.
设置，比如文本大小或其他的事情

372
00:17:57,176 --> 00:17:59,643
So these simulators are truly simulating the device, they're
所以这些模拟器就像真的设备一样，它们不仅仅

373
00:17:59,712 --> 00:18:03,213
not just running your app only. So that's kinda cool.
是运行你的应用而已。这很酷的

374
00:18:03,282 --> 00:18:04,982
And we can always go back to our app. Just go back here and
我们随时都可以回到我们的应用。只要

375
00:18:05,051 --> 00:18:09,187
say Concentration, here's Concentration. All right,
点一下 Concentration，这就是翻牌应用了。好了

376
00:18:09,255 --> 00:18:12,490
so now we're familiar with Xcode and kind of
现在我们熟悉了 Xcode 和所有组件

377
00:18:12,558 --> 00:18:15,492
all its pieces right here. Let's take a look at the files
的一部分。让我们看一下那些 Xcode

378
00:18:15,561 --> 00:18:18,262
that were created for us. Now, There are six files but
为我们创建的文件。这里有六个文件但是

379
00:18:18,331 --> 00:18:21,299
actually we're only gonna look at two of them. For example,
实际上我们仅仅需要看其中两个。举个例子

380
00:18:21,367 --> 00:18:24,268
this one, assets, right here, that's your images,
这个 Assets 是你的图片

381
00:18:24,337 --> 00:18:27,037
including your app icon, which we haven't set,
包括你的应用图标，我们还没设置

382
00:18:27,106 --> 00:18:29,940
I don't really need that. Your launch screen right here, I'm
我并不太需要它。你的启动屏幕

383
00:18:30,009 --> 00:18:33,043
selecting that as well. This app delegate up here, we don't
我也一同选中。还有 AppDelegate

384
00:18:33,112 --> 00:18:35,679
need to touch any of these to make our Concentration app. So
我们在编写翻牌应用时不需要碰这三个文件

385
00:18:35,748 --> 00:18:38,282
I'm selecting them all and I'm going to right-click on them,
所以我选中然后右键他们

386
00:18:38,350 --> 00:18:41,819
and go down to new group from selection, and put them in
选中 New Group from Selection，把它们放到

387
00:18:41,888 --> 00:18:45,255
a group. And I'm going to call that group Supporting Files,
一个组里，然后我会把它叫做 Supporting Files

388
00:18:45,324 --> 00:18:46,457
because that's what they are,
因为那就是它们的本质

389
00:18:46,525 --> 00:18:50,461
they're supporting files. By the way, I would not
他们是支持性文件。顺便说一句，我不会

390
00:18:50,529 --> 00:18:53,330
put your info.plist in your Supporting Files,
把 Info.plist 放到 Supporting Files 里

391
00:18:53,399 --> 00:18:57,935
leave that at the top level. It seems to be better. So
把它留在第一级，这看起来更好

392
00:18:58,003 --> 00:19:00,904
this other file here, ViewController.swift,
剩下的文件，ViewController.swift

393
00:19:00,973 --> 00:19:03,741
is just some Swift code, we'll get to that in a second. And
是一些 Swift 代码，我们会过一会儿研究它

394
00:19:03,809 --> 00:19:07,678
right here, Main.storyboard, that's your UI.
Main.storyboard 里是你的 UI

395
00:19:07,747 --> 00:19:10,914
Now you're gonna build your UI in Xcode graphically,
你将要在 Xcode 中图形化地构建你的 UI

396
00:19:10,983 --> 00:19:13,517
okay you're not gonna code it up, you're gonna do it
你不会用代码构建它，你将用

397
00:19:13,586 --> 00:19:16,387
graphically. And not only that the way you're gonna build it,
图形的方式。不仅仅是你要以这样子的方式构建它

398
00:19:16,455 --> 00:19:17,821
you're gonna drag out buttons and
你要拖拽按钮

399
00:19:17,890 --> 00:19:20,257
text fields and sliders and things like that.
文本输入, 滑杆等其他控件

400
00:19:20,326 --> 00:19:22,726
And it's going to actually put real buttons and
它将把真正的按钮

401
00:19:22,795 --> 00:19:26,129
real sliders live on the screen at a time. And
滑杆放置到屏幕上

402
00:19:26,198 --> 00:19:28,399
you're going to edit them and set them up the way you want.
你可以用你喜欢的方式编辑他们

403
00:19:28,468 --> 00:19:30,167
And then when you run them on your app,
然后当你运行你的应用时

404
00:19:30,235 --> 00:19:32,903
it kind of freeze dries them, brings them over and
就如同冰冻了他们，然后给他们

405
00:19:32,972 --> 00:19:36,306
adds water and they come back to life. And then they run. So
添加一些水，他们就恢复了生机。然后他们就运行了起来

406
00:19:36,375 --> 00:19:39,109
when you run, it's not like you don't click a button here
所以当你运行的时候，它不像是，你没有点击按钮

407
00:19:39,178 --> 00:19:41,679
and it generates a lot of code to put those buttons there.
它生成许多代码来将那些按钮放置到哪里

408
00:19:41,748 --> 00:19:45,249
It's actually editing these buttons live. Now,
它实际上是编辑那些按钮，让它们活过来

409
00:19:45,317 --> 00:19:48,552
notice that I got this, sort of, iPhone shaped rectangle.
现在，注意我有了这个，像 iPhone 一样形状的矩形

410
00:19:48,621 --> 00:19:51,655
Can you all see that? Yeah, it looks pretty good. This iPhone
你们都能看到么？好的，它看起来很不错。这个 iPhone

411
00:19:51,724 --> 00:19:55,058
shaped rectangle is where I'm going to edit my UI. And in
形状的矩形就是你要编辑你的 UI 的地方

412
00:19:55,127 --> 00:19:59,463
particular this is an iPhone 8 sized rectangle, you see that?
特别的，这是一个 iPhone 8 尺寸大小的矩形，你们看得到么？

413
00:19:59,532 --> 00:20:03,300
It says view as iPhone 8 down here. I can click on this and
这下面写着 view as iPhone 8。我能单击这里

414
00:20:03,369 --> 00:20:07,271
actually look at other iOS devices. So I can look at
然后查看其它的 iOS 设备。所以我能看到

415
00:20:07,340 --> 00:20:10,107
my UI, how it would look let's say on an iPad.
我的 UI，它是如何在一台 iPad 上呈现的

416
00:20:10,176 --> 00:20:14,011
Now an iPad is huge so maybe I wanna zoom down a little bit
一台 iPad 是大的所以我想缩小一点点

417
00:20:14,080 --> 00:20:18,315
to see it better. I can also look at it in landscape mode.
让它看起来更好。我还可以在横屏模式下查看

418
00:20:18,384 --> 00:20:20,918
So here's portrait and landscape of an iPad, for
因为 iPad 有横屏和竖屏，就像这样

419
00:20:20,986 --> 00:20:23,454
example. I could go to a different kind of iPhone,
我可以用不同种类的 iPhone

420
00:20:23,523 --> 00:20:28,025
like here's my iPhone X, all right? So I can look at
就像这是 iPhone X。我能用

421
00:20:28,094 --> 00:20:32,163
all possible iOS devices and see how my UI looks.
所有可能的 iOS 设备来查看我的 UI

422
00:20:32,231 --> 00:20:35,766
Now our goal eventually, once we learn enough about iOS,
现在我们最终的目标是，我们学习足够多的关于 iOS 的知识

423
00:20:35,835 --> 00:20:39,737
is to build UIs that look good even if they're in landscape
去构建 UI，让它无论在哪里看起来很都很棒

424
00:20:39,806 --> 00:20:44,108
or portrait, iPad, iPhone 8, iPhone 8+, which is big,
不管它是在横屏还是竖屏，iPad，iPhone 8，还是大一点的 iPhone 8 Plus

425
00:20:44,176 --> 00:20:47,411
iPhone X, it doesn't matter. Okay that's our goal.
iPhone X 都没关系。那就是我们的目标

426
00:20:47,479 --> 00:20:51,148
Now in the first week, I can't teach you any of that, so
如今在第一周，我还不能教你这个事情

427
00:20:51,217 --> 00:20:52,917
we're gonna have our UI just
所以我们将会让我们的 UI 仅仅

428
00:20:52,985 --> 00:20:55,252
try and look good on an iPhone X.
在 iPhone X 上看起来不错

429
00:20:55,321 --> 00:20:57,154
But next week, not to worry we'll try to make it so
但是下周，我们将会尝试

430
00:20:57,223 --> 00:20:59,490
it looks good on other iPhones as well. And
让它在其他 iPhone 上也看起来不错

431
00:20:59,558 --> 00:21:02,960
your assignment two is gonna really ask you to make
你们的作业二将会要求你制作一个

432
00:21:03,028 --> 00:21:07,765
an app that just looks good on all possible iOS devices.
能够在所有的 iOS 设备上看起来都很好的应用

433
00:21:07,833 --> 00:21:10,234
Now on the left over here, when we brought up this,
如今左边的区域，我们所在的

434
00:21:10,303 --> 00:21:13,704
this area in Xcode by the way is called Interface Builder
这片区域在 Xcode 中叫做 Interface Builder

435
00:21:13,773 --> 00:21:15,406
because we're building our user interface,
因为我们将要在这里搭建我们的用户界面

436
00:21:15,474 --> 00:21:19,176
so Interface Builder. This area over here is essentially
所以叫做 Interface Builder。这片区域

437
00:21:19,245 --> 00:21:20,911
all the things that are here but
包含基本上所有这里的东西

438
00:21:20,979 --> 00:21:23,413
in text form, like a text outline.
只不过是以文本的形式，像一个文本大纲

439
00:21:23,482 --> 00:21:24,715
And I'm gonna hide that,
我会通过下方的这个小按钮

440
00:21:24,784 --> 00:21:26,217
you do that with this little button down here,
来隐藏它

441
00:21:26,285 --> 00:21:27,718
see it says hide document outline.
看它上面写着 Hide document outline

442
00:21:27,786 --> 00:21:31,054
I'm gonna click that to hide that. We'll go and hide this
我会点击它，把它隐藏。我们也要隐藏

443
00:21:31,123 --> 00:21:34,992
phone chooser as well and we have our little UI here.
这个设备选择器，这样我们有了我们的 UI 界面

444
00:21:35,061 --> 00:21:37,328
We'll look at that document outline later in the quarter.
我们会在这学期之后的时间查看这个文件大纲

445
00:21:40,066 --> 00:21:43,067
I want to build my UI, how do I build a UI?
我想要搭建我的 UI，我该如何搭建我的 UI 呢？

446
00:21:43,135 --> 00:21:45,336
Okay I'm trying to build Concentration here.
我想要制作翻牌应用

447
00:21:45,404 --> 00:21:49,473
So I'm going to need some cards. And I'm going to
所以我会需要一些卡牌

448
00:21:49,541 --> 00:21:52,008
use a button to represent a card, which is kind of cool,
我会用一个按钮来代表一张卡牌，那是蛮酷的

449
00:21:52,077 --> 00:21:53,310
because you tap on a button and
因为你轻击一个按钮

450
00:21:53,378 --> 00:21:54,445
it does something. And that's good,
然后它做出一些反应，那很棒

451
00:21:54,513 --> 00:21:57,314
because when you tap on a button I want it to flip over.
因为当你轻击一个按钮，我想要让它翻转

452
00:21:57,383 --> 00:21:58,682
Okay, I'm going to have my cards flip over. So
好的，我想要我的卡牌翻转

453
00:21:58,751 --> 00:22:01,252
that's the first thing you do. Let's build one card that will
这是你需要做的第一件事情。让我们制作一张卡牌

454
00:22:01,320 --> 00:22:04,288
flip over when we click on it all right. So
当我们点击它，它就会翻转

455
00:22:04,356 --> 00:22:06,690
I'm going to zoom in, by the way, you can hold down alt.
我会缩放一些，顺便说一下，你可以按住 alt 键

456
00:22:06,758 --> 00:22:09,960
You see in the lower left I have a thing here that shows
你可以看到在左下角我放了一个东西来展示

457
00:22:10,029 --> 00:22:12,196
when I'm pressing alt, and control, and command,
我正在按的键位，如 alt， control，command

458
00:22:12,264 --> 00:22:14,097
and all that stuff. If you hold down alt and
和其他任何键。当你按住 alt

459
00:22:14,166 --> 00:22:17,100
use your mouse wheel you can zoom in and out, on your
用你的鼠标滑轮滑动，就可以缩小和放大

460
00:22:17,169 --> 00:22:19,936
UI, which is kind of cool. Otherwise your mouse wheel
你的 UI, 那是蛮酷的。若不按住 alt 键，滑动鼠标滑轮

461
00:22:20,005 --> 00:22:22,539
moves it up and down, which is also kinda cool. All right so
会让它上下移动，这也很酷

462
00:22:22,608 --> 00:22:26,677
we have our UI here, how do we put a button in this UI? Okay,
我们有了 UI, 该如何放一个按钮到 UI 上呢？

463
00:22:26,745 --> 00:22:30,480
as promised, we go over to this thing that had a top and
正如承诺的，我们来到这个有着一个顶部和底部

464
00:22:30,549 --> 00:22:31,849
a bottom, called the utilities pane.
的东西，它叫工具栏

465
00:22:31,917 --> 00:22:34,985
And we're going to look in the bottom to start, and
我们将要从底部开始

466
00:22:35,054 --> 00:22:39,189
specifically, in this object library tab. And
明确说，是这个 object library (对象库) 表格

467
00:22:39,258 --> 00:22:42,125
we're going to see a whole bunch of objects, remember,
我们将会看到全部的对象类型，记住

468
00:22:42,194 --> 00:22:44,161
and I mean objects like in an object-oriented sense,
我说的对象就是面向对象里的对象

469
00:22:44,229 --> 00:22:46,830
this is all object-oriented. And all these objects,
这些全部都是面向对象的。所有的这些对象

470
00:22:46,899 --> 00:22:50,634
like labels and buttons and text fields and switches,
像标签，按钮，文字输入和开关

471
00:22:50,703 --> 00:22:56,039
even web views and table views and text views and even ARKit.
甚至网页视图，表视图，文本视图甚至 ARKit

472
00:22:56,108 --> 00:22:59,176
Here's a little ARKit of augmented reality views.
这是 ARKit 中的一个小的增强现实视图

473
00:22:59,245 --> 00:23:01,111
These things can all be dragged out,
这些东西全都可以被拖拽

474
00:23:01,180 --> 00:23:03,947
multi touch gestures, dragged out to build your user
还有多触控手势，拖拽来搭建你的用户界面

475
00:23:04,016 --> 00:23:07,451
interface. Okay and I'm going to cover the vast majority of
我将会涉及在这个非常大的列表里的

476
00:23:07,519 --> 00:23:09,586
the stuff in this very large list right here.
很多的主要控件

477
00:23:09,655 --> 00:23:12,489
But we're going to start with a simple one which is towards
但是我们将以一个非常简单的开始

478
00:23:12,558 --> 00:23:13,990
the top, which is buttons. So
那就是上面的按钮

479
00:23:14,059 --> 00:23:16,260
I just wanna drag a button into my UI, and
我将会拖拽一个按钮到我的 UI 上

480
00:23:16,329 --> 00:23:19,129
I just drag it in, I pick it up with mouse, and
我仅需要拖住，点击我的鼠标

481
00:23:19,198 --> 00:23:22,699
drop it in my UI. Now, when I move this around,
然后把它丢到我的 UI 上。现在，当我四周移动它

482
00:23:22,768 --> 00:23:25,202
look at these blue lines, see these blue lines.
看这些蓝色的线，看这些蓝色的线

483
00:23:25,271 --> 00:23:28,505
They're trying to help me put it exactly in the middle, or
它们尝试帮我把它放置到正中间的位置

484
00:23:28,574 --> 00:23:30,507
exactly in the middle on the bottom edge,
或者底部边缘正中间的位置

485
00:23:30,576 --> 00:23:32,509
or up in the upper right corner.
或者右上角的位置

486
00:23:32,577 --> 00:23:36,046
These blue lines are critical to building a UI that will
这些蓝色的线对于构建你的 UI 来说非常的重要

487
00:23:36,115 --> 00:23:39,283
work when you rotate or on a bigger device or whatever. But
当你旋转屏幕或者到一台更大的设备上时，它们会起到重要作用

488
00:23:39,352 --> 00:23:40,751
we're gonna ignore the blue lines for now
但是我们暂时忽略这些蓝色的线

489
00:23:40,819 --> 00:23:42,719
because I said I'm gonna teach you that next week,
因为我说过我会在下周教给你们

490
00:23:42,788 --> 00:23:45,722
all right? So here's my button, it's very, very small.
好么？所以这是我的按钮，非常非常小

491
00:23:45,791 --> 00:23:48,591
I want it to be bigger. Well, I can just grab these handles
我想让它大一点。好的，我可以抓住这些边缘上的柄

492
00:23:48,660 --> 00:23:51,962
on the edge here and resize it to whatever size that I want.
然后缩放到我想要的尺寸

493
00:23:52,031 --> 00:23:54,230
Maybe make it a little more card shaped or
把它的大小设置成卡牌那么大

494
00:23:54,299 --> 00:23:57,901
something like that. And I could also edit the text on
我还可以编辑文本

495
00:23:57,970 --> 00:23:59,836
here by double-clicking on this.
通过双击这个东西

496
00:23:59,905 --> 00:24:01,972
I don't want Button maybe, but let's do the back of the card,
我可能不太想要这个按钮，让我们做卡牌的背面

497
00:24:02,041 --> 00:24:03,340
let's see what the back of the card looks like.
让我们看看卡牌的背面是什么样子

498
00:24:03,409 --> 00:24:04,808
So I'm just gonna delete it,
所以我只要删除它

499
00:24:04,877 --> 00:24:07,744
so now my button has no text on it, all right,
现在我的按钮没有了文字

500
00:24:07,813 --> 00:24:10,647
which is fine. How about setting the background color
这是不错的。把背面颜色设置成

501
00:24:10,716 --> 00:24:13,317
to orange, these cards orange, and our Halloween theme here,
橙色怎么样，那些卡牌是橙色的，我们还有万圣节主题

502
00:24:13,386 --> 00:24:15,552
they have orange background. How do I do that?
他们会有橙色的背景色。我该如何做呢？

503
00:24:15,620 --> 00:24:20,090
Well, that's the top of this utilities pane. Notice that
好吧，那在我们工具栏的顶端。注意

504
00:24:20,158 --> 00:24:23,660
when I select a button, I get this UI over here that is
当我选中一个按钮，我得到了这个页面

505
00:24:23,729 --> 00:24:26,930
specific to setting the attributes of a button. And
这是具体设置这个按钮的属性的地方

506
00:24:26,999 --> 00:24:29,266
not only that, it's object-oriented. So
不仅仅是这样，它是面向对象的

507
00:24:29,334 --> 00:24:32,836
I have the button stuff here and as I scroll down, look,
所以我有一个按钮的对象，并且当我下滑，看

508
00:24:32,905 --> 00:24:37,140
I get UI for a control because button inherits from control.
我得到了一个关于 Control 的界面，因为 UIButton 继承自 UIControl

509
00:24:37,209 --> 00:24:40,010
And then control inherits from view. So
而 UIControl 继承自 UIView

510
00:24:40,079 --> 00:24:43,013
I get UI to enter to view because a button is a view,
所以我又得到了一个 view 的界面，因为一个按钮就是一个视图

511
00:24:43,082 --> 00:24:46,550
right? It inherits from view in the object-oriented sense.
对吧？通过面向对象来讲，它继承自 UIView

512
00:24:46,619 --> 00:24:50,620
So the background of any view is settable here in this UI.
所以任何一个视图的背景都可以在这个界面里设置

513
00:24:50,689 --> 00:24:53,190
It's right here under View, it says Background.
它就在这里，在 View 下，它叫做 Background (背景)

514
00:24:53,258 --> 00:24:56,393
Right now the background is clear, that little line
现在背景是透明的，那条

515
00:24:56,462 --> 00:24:59,196
through a thing means clear. So there is no background, so
穿过的线意味着透明。所以这里没有背景

516
00:24:59,265 --> 00:25:03,300
it's showing the white from behind is showing through. But
所以它才会展示它后面的白色

517
00:25:03,368 --> 00:25:06,169
I can easily change this to orange by clicking there and
但是我能轻松的改变它为橙色，通过点击哪里

518
00:25:06,238 --> 00:25:06,870
going down here. You know,
然后向下，你看

519
00:25:06,939 --> 00:25:09,239
there's a lot of preset colors here.
这里有许多预先设置好的颜色

520
00:25:09,308 --> 00:25:12,609
I can go to Other and pick it by name, I could pick orange.
我可以点击 Other 然后通过名称选中橙色

521
00:25:12,678 --> 00:25:15,211
I could pick a crayon that looks orange,
我能够选中一个看起来像橙色的蜡笔

522
00:25:15,280 --> 00:25:17,881
color wheel, whatever. But here I want orange, so
颜色转盘，无论什么。但是我想要橙色

523
00:25:17,950 --> 00:25:18,816
I'll just pick it by name. And
所以我仅仅需要通过名字来挑选

524
00:25:18,884 --> 00:25:21,518
now I've set the background of my card to be orange, so
现在我已经设置卡牌的背景是橙色

525
00:25:21,587 --> 00:25:24,254
that's good. That's looking pretty much exactly like this,
那是不错的。那看起来和这个非常像

526
00:25:24,323 --> 00:25:27,657
I'm happy with it so far. And in our Halloween theme,
迄今为止我非常开心。在我们的万圣节主题里

527
00:25:27,726 --> 00:25:31,929
to make it even scarier, let's make the background here
为了让它看起来更可怕，我们设置这里的背景

528
00:25:31,998 --> 00:25:35,365
be black. So I'm gonna change this to be black.
为黑色。所以我要把它改成黑色

529
00:25:35,434 --> 00:25:37,233
And the way I do that is I just click on it and
方式也是我仅仅需要点击它

530
00:25:37,302 --> 00:25:39,870
now this right-hand side doesn't say button on the top.
现在右手边的顶端就不是写着 button

531
00:25:39,938 --> 00:25:42,972
It say view because this big space is just a blank view.
它写着 view 因为这个大的空间是一个空白的视图

532
00:25:43,041 --> 00:25:45,575
It's not a button view or anything. It's just a view,
它不是一个按钮或其他东西。它就是一个视图

533
00:25:45,644 --> 00:25:48,111
but it's got this background thing, same way. So
但是它设置背景的方式是一样子的

534
00:25:48,180 --> 00:25:50,647
I click on it, and here I'll just pick it from this list of
所以我点击它，然后从列表里选中

535
00:25:50,716 --> 00:25:54,384
predefined things. Black color, and now, I have a nice
之前定义好的东西，黑色，现在我有了一个好看的 UI

536
00:25:54,452 --> 00:25:58,388
orange on black UI. Looking pretty cool. Now, what about
橙色的卡牌在黑色的背景下。它看起来很酷。现在

537
00:25:58,456 --> 00:26:00,891
when the cards are face up? Well, when they're face up,
当卡牌面朝上的时候是什么样子。好的，当它们面朝上

538
00:26:00,960 --> 00:26:03,160
they're white. And then they have an image on them.
它们是白色的，并且有一个图案

539
00:26:03,228 --> 00:26:06,630
Now I could have the cat or the spider web here or
我能放一只小猫或者蜘蛛网

540
00:26:06,698 --> 00:26:09,733
whatever be some JPEG image or something. But
或任意一张 JPEG 图片或其他东西。但是

541
00:26:09,802 --> 00:26:12,969
I got a really cool idea to make this be real easy, let's
我有一个很酷的想法让它很简单，让我们

542
00:26:13,038 --> 00:26:16,339
make it be an emoji. Cuz if we just put an emoji in here,
放一个 emoji。因为如果我们仅仅放一个 emoji 在上面

543
00:26:16,408 --> 00:26:18,909
then we have a lot of choices. And it's really easy and
我们就有了很多选择。那是非常简单

544
00:26:18,978 --> 00:26:21,177
we don't have to go find the images or anything like that.
并且我们不必找图片或者其他东西

545
00:26:21,246 --> 00:26:22,278
So that's what we're gonna do. So
这就是我们将要做的

546
00:26:22,347 --> 00:26:25,983
I'm gonna make this look like the front of the card. So I'm
所以我将在卡牌的正面弄成那样子

547
00:26:26,051 --> 00:26:28,786
gonna go down here and change this orange back to white,
我要向下一点，把这个橙色变成白色

548
00:26:28,854 --> 00:26:31,622
okay, this white color. And I'm gonna put on here,
好的，这个白色。然后我要放到这里

549
00:26:31,690 --> 00:26:34,792
instead of blank, I'm gonna put an emoji. Most Mac apps,
代替白色，我会放一个 emoji。大部分 Mac 应用

550
00:26:34,860 --> 00:26:37,094
if you go to their Edit menu, at the bottom of it,
如果你去到 Edit 菜单，在它的底部

551
00:26:37,163 --> 00:26:39,796
there's this emoji and symbols. I don't know how, how
这里有一个 emoji and symbols, 我不知道有多少

552
00:26:39,865 --> 00:26:42,566
many of you know that. But if you go to emoji and symbols,
你们有多少人知道这个。但是如果你点击 emoji and symbols

553
00:26:42,635 --> 00:26:45,068
you get this window right here that lets you choose
你会立刻得到一个窗口让你选择

554
00:26:45,137 --> 00:26:48,538
all these various emoji. We got a Halloween theme here, so
各种emoji。我们有一个万圣节的主题，所以

555
00:26:48,607 --> 00:26:52,275
let's look for a ghost. Yeah, Mr. Ghost, right there.
我们查找一下 幽灵。好的，幽灵先生就在这里了

556
00:26:52,344 --> 00:26:54,778
Okay, so that's a good, he looks like a fun ghost even.
好的，那是不错的，他看起来甚至像一个有趣的幽灵

557
00:26:54,846 --> 00:26:57,414
We'll double-click right there to put him on the card and
我们要双击这个来把它放到卡牌上

558
00:26:57,482 --> 00:27:00,884
there he is. He's very, very tiny. I could go zoom in and
然后它就在这里了。不过非常，非常的小。我能够放大

559
00:27:00,953 --> 00:27:04,021
look at them. But he's even small compared to the size of
然后看一下它。但是它还是太小了，比起

560
00:27:04,089 --> 00:27:07,257
the iPhone X. If my user was doing this, they'd be like,
iPhone X 的尺寸。如果我的用户在使用它，他们可能会说

561
00:27:07,325 --> 00:27:10,093
what is that. It was just like a little smudge. So
那是什么？那会是一个小的污点

562
00:27:10,162 --> 00:27:12,262
we wanna make this much larger. So again,
所以我们要把它放大一点。在一起

563
00:27:12,331 --> 00:27:15,465
I'm going to the top side, top half of this utilities pane.
我去到顶端部分，工具窗口的上半部分

564
00:27:15,534 --> 00:27:19,703
And if I look down here, look, font, system font 15 point.
如果我往下看，字体，系统字体15号

565
00:27:19,771 --> 00:27:21,638
So I'm gonna make that way bigger,
我要让它大一点

566
00:27:21,707 --> 00:27:23,540
let's make it 50 point.
让我们调到50号字

567
00:27:23,609 --> 00:27:28,411
Now we got a nice big ghost. Awesome,
现在我们有了一个大幽灵，酷

568
00:27:28,480 --> 00:27:33,149
we have got all we needed in terms of design to do our UI.
我们有了有关于我们 UI 设计的一切

569
00:27:33,218 --> 00:27:35,952
Let's go ahead and run and see what happens here.
让我们直接运行看看会发生什么

570
00:27:36,021 --> 00:27:38,688
See if this black background and this ghost and
看是否这个黑色的背景和幽灵还有

571
00:27:38,757 --> 00:27:41,624
all this stuff is showing up in our app when we run.
全部的这些出现在我们的应用里

572
00:27:41,693 --> 00:27:44,595
And of course it will be, here it is. And when I click on it,
当然它会的，这里就是了。当我点击它

573
00:27:44,663 --> 00:27:46,730
can you see that it's flashing a little bit there?
你们刚看到它在轻微的闪烁么？

574
00:27:46,798 --> 00:27:48,865
That's saying, that's giving me a little feedback, yeah,
这意味着，它给了我一点小小的反馈

575
00:27:48,934 --> 00:27:49,600
you touched on that.
是的，你触碰了它

576
00:27:49,668 --> 00:27:52,469
It's nice, but it doesn't do anything, right?
这是不错的，但是它没有做任何的反应，对吧？

577
00:27:52,538 --> 00:27:53,904
And we want it to do something.
我们想要它做一些事情

578
00:27:53,973 --> 00:27:59,810
Mainly we want it to flip over. So let's go do that.
主要的，我们想让它翻转。所以让我们做吧

579
00:27:59,878 --> 00:28:03,146
How do we make it so something in the UI does something?
我们该如何让 UI 里的东西能做什么事情呢？

580
00:28:03,214 --> 00:28:05,782
Well, we're gonna hook it up to some code. Specifically,
好的，我们将把它和一些代码挂钩。明确的讲

581
00:28:05,851 --> 00:28:09,019
we're gonna hook it up to this Swift code right here.
我们会把它和一些 Swift 代码挂钩

582
00:28:09,088 --> 00:28:10,954
Now they gave us these things right here,
现在它们给了我们这些东西

583
00:28:11,022 --> 00:28:13,289
which I'm gonna delete so as not to distract you.
我会删掉它们不要让它们干扰到你

584
00:28:13,358 --> 00:28:16,059
But this is your first look at Swift code.
但这是你看到 Swift 代码的第一眼

585
00:28:16,128 --> 00:28:18,361
Let's look at it real quick, see what it does. Import,
让我们快速看一眼，它做了什么。Import

586
00:28:18,430 --> 00:28:21,564
it's just like include. It's just bringing all of UIKit
它就像是 include，它即是把 UIKit 的全部内容带来

587
00:28:21,633 --> 00:28:25,602
in for our use. UIKit is iOS's framework that has buttons and
为我们所用。UIKit 是 iOS 的框架，包含按钮

588
00:28:25,671 --> 00:28:28,171
sliders and all that stuff.
滑杆和所有内容

589
00:28:28,240 --> 00:28:31,674
Kinda that top cocoa touch layer we're talking about.
就是我们讨论过的顶端的 Cocoa Touch 层

590
00:28:31,743 --> 00:28:35,445
So this is the declaration of a class, in an object-oriented
所以这是定义了一个类，这是面向对象的概念

591
00:28:35,514 --> 00:28:38,615
sense, a class. Of course we use the keyword class.
定义一个类，当然用关键字 class

592
00:28:38,684 --> 00:28:41,351
This is the name of the class, ViewController.
然后是类的名字，ViewController

593
00:28:41,420 --> 00:28:44,921
This is not a very good name, it's very generic. Probably
这并不是什么好名字，太广泛了。最好

594
00:28:44,990 --> 00:28:47,790
this wants to be called ConcentrationViewController or
这个应该叫做 ConcentrationViewController

595
00:28:47,859 --> 00:28:51,395
something like that. Do not change the name of this in
或者类似的名字。不要更改这个类的名字

596
00:28:51,464 --> 00:28:54,297
your homework, okay? Changing the name of
好吗？在你的作业里面更改这个名字

597
00:28:54,366 --> 00:28:56,566
this requires a little more than just changing it
有比仅仅在这里更改它的名字更多的步骤

598
00:28:56,635 --> 00:28:59,136
right here, because it's also showing up in your UI.
因为这个会展示到用户界面上

599
00:28:59,204 --> 00:29:02,072
So you have to change it in a way that it changes in both
如果你要改的话，那两个地方都要改

600
00:29:02,141 --> 00:29:05,942
places. This is its super class. This is
这是它的父类

601
00:29:06,011 --> 00:29:09,112
Object-Oriented Programming. We have inheritance.
这是面向对象编程，所以我们有继承

602
00:29:09,181 --> 00:29:11,715
It's inheriting from UIViewController.
它继承了 UIViewController

603
00:29:11,784 --> 00:29:15,085
Class UIViewController is in UIKit. You can tell because it
UIViewController 是 UIKit 中定义的。你可以从

604
00:29:15,154 --> 00:29:17,887
starts with UI. And what that class does,
它名字以 UI 开头看出来。这个类的作用

605
00:29:17,956 --> 00:29:22,092
it knows everything about controlling a UI like this.
它知道如何控制像这样的用户界面

606
00:29:22,161 --> 00:29:25,161
That's what it does. So by having our ViewController
这就是它的功能。让我们的 ViewController

607
00:29:25,230 --> 00:29:28,398
inherit from that, it inherits all the capability to control
继承它，就继承了所有控制的能力

608
00:29:28,467 --> 00:29:30,834
that thing. So all we have to do is put the code that has
所以我们只需要把代码

609
00:29:30,902 --> 00:29:32,736
to do with the Concentration game in here, so
和翻牌游戏相关的代码放在这里

610
00:29:32,804 --> 00:29:36,206
that's great. Then inside this curly brace, we're gonna
这很不错。在这对大括号里，我们

611
00:29:36,275 --> 00:29:39,009
put all our methods and instance variables. Who
所有的方法（method）和实例变量都放这里

612
00:29:39,077 --> 00:29:41,745
does not know what the word method or instance variable
谁不知道“方法”或者“实例变量”的意思？

613
00:29:41,813 --> 00:29:44,814
means? Okay, good, everybody does. And you should because
好，很好，大家都知道。你应该知道

614
00:29:44,883 --> 00:29:47,050
that's fundamentally an Object-Oriented Programming,
这是面向对象编程的基础

615
00:29:47,118 --> 00:29:49,219
right? So we're gonna put all our instance variables and
是吧？所以我们把所有的实例变量和

616
00:29:49,287 --> 00:29:51,254
methods inside those curly braces.
方法都放在这对大括号里面

617
00:29:51,323 --> 00:29:54,624
That's how we're gonna declare our class. So how are we
这就是我们声明类的方法。那我们

618
00:29:54,693 --> 00:29:57,660
gonna make this button do something here? Well,
怎么才能让这个按钮做些什么呢？

619
00:29:57,729 --> 00:30:00,663
what we're gonna do is we're gonna create a method in here.
我们要做的是，我们在这里创建一个方法

620
00:30:00,732 --> 00:30:01,531
And we're gonna make it so
我们要让它做到

621
00:30:01,600 --> 00:30:04,934
that when you press this button, it calls that method,
当你按下这个按钮，它就调用这个方法

622
00:30:05,003 --> 00:30:07,137
of course. How are we gonna do that?
当然了。那我们怎么做呢？

623
00:30:07,205 --> 00:30:11,241
To do that, believe it or not, we need to get this UI and
不管你信不信，要实现这个，我们需要让 UI

624
00:30:11,309 --> 00:30:15,012
this code over here on the screen at the same time.
和这个代码同时出现在屏幕上

625
00:30:15,080 --> 00:30:18,181
And we do that with this little button right here.
我们按这里的这个按钮

626
00:30:18,250 --> 00:30:19,716
This little circles thing right here,
这个画着圆圈的按钮

627
00:30:19,784 --> 00:30:22,652
this is called the assistant editor. And when I click it,
这是 Assistant（助理）编辑器。当我点击它

628
00:30:22,720 --> 00:30:25,822
they come on screen, both of them on screen, at the same
它们就出现了，同时显示在屏幕上

629
00:30:25,891 --> 00:30:29,859
time. And I can adjust this space however I want.
我可以随意调整它们的大小

630
00:30:29,928 --> 00:30:31,194
Maybe we'll get rid of this now.
我先在可以先隐藏这个

631
00:30:31,263 --> 00:30:36,099
All right, so here's my UI and my code on screen at the same
好，我们的 UI 和代码同时显示出来了

632
00:30:36,168 --> 00:30:39,202
time. Now, why do I want them on screen at the same time if
为什么我想要他们同时出现

633
00:30:39,271 --> 00:30:42,605
I need to hook them up? Because the way I hook them
来关联他们？因为我关联他们的方法

634
00:30:42,674 --> 00:30:47,376
up is I hold down the Ctrl key and drag a line from the UI to
是按住 control 键不放，然后点击 UI 上（的按钮），再拖出一条线

635
00:30:47,445 --> 00:30:50,280
my code. I know that's kinda weird, but
到代码里。我知道这挺怪的

636
00:30:50,349 --> 00:30:54,017
that's how we do it. And when we let go of that drag line,
但这就是我们实现的方法。当我们松开鼠标的时候

637
00:30:54,085 --> 00:30:57,286
it says, you will make a connection between UI and
他会问，你将要建立 UI 和代码的关联

638
00:30:57,355 --> 00:30:59,856
code. No problem, what kinda connection would you like?
没问题，那是什么样的关联呢？

639
00:30:59,925 --> 00:31:01,992
You can make an action, which is a method, or
你可以创建操作（Action），也就是一个方法

640
00:31:02,061 --> 00:31:03,493
one of these two outlet things,
或者这两种出口（Outlet）中的一种

641
00:31:03,562 --> 00:31:06,029
which I'm gonna talk about later in this lecture. So
我这节课之后也会讲到

642
00:31:06,098 --> 00:31:08,732
let's start with this action one. An Action connection
所以我们这里是用 Action 这个选项。关联一个操作

643
00:31:08,800 --> 00:31:11,401
means when this button is pressed, call a method.
的作用是按下按钮的时候，就调用这个方法

644
00:31:11,470 --> 00:31:13,336
And I get to say what the name of the method is.
然后我要命名这个方法

645
00:31:13,404 --> 00:31:16,005
I'm gonna call it touchCard, cuz that's what's happening,
我要叫它 touchCard，因为这就是发生的事情

646
00:31:16,074 --> 00:31:19,142
someone's touching on this card. And this method that's
也就是有人点击了这张卡片。然后这个方法

647
00:31:19,211 --> 00:31:21,378
gonna be created for me, it can have arguments,
要创建的方法可以通过 Arguments 指定参数

648
00:31:21,446 --> 00:31:23,947
it could have no arguments, that's none. Or
也可以没有参数，也就是 None 这个选项

649
00:31:24,016 --> 00:31:26,450
it could have one argument, which is the sender,
也可以有一个参数，也就是 Sender

650
00:31:26,518 --> 00:31:29,219
in other words, the button that is sending me this.
换句话说，就是调用这个方法的按钮

651
00:31:29,288 --> 00:31:30,620
I really need that argument,
我非常需要这个参数

652
00:31:30,689 --> 00:31:32,789
because when this touch card gets sent to me,
因为 touchCard 被调用了

653
00:31:32,858 --> 00:31:35,459
I need to flip it over. So, I have to talk to it, okay, so
我需要把那张牌翻过来，所以我需要能访问它

654
00:31:35,527 --> 00:31:38,195
I want that argument. And really important,
所以我想要这个参数。非常重要的一点

655
00:31:38,263 --> 00:31:41,131
pay attention right now if, if you're dozing right now,
打瞌睡的注意了

656
00:31:41,200 --> 00:31:44,034
is that we do not. This is the type of the arguments.
我们不能，注意这里这个是参数的类型

657
00:31:44,102 --> 00:31:47,704
See it says Type Any? And we want that type to be Button,
看到它写的是 Any 了吗？但我希望参数是按钮的类型 UIButton

658
00:31:47,773 --> 00:31:50,807
okay? Because a button is sending this method to us.
好吗？因为是这个按钮调用了这个方法

659
00:31:50,876 --> 00:31:52,709
Now I don't know why that doesn't default to Button.
我不知道为什么不是默认为按钮的类型

660
00:31:52,778 --> 00:31:55,245
I've been seeing that for years, it should. But
好多年我看到的都是这样，本因该是按钮的类型

661
00:31:55,314 --> 00:31:58,181
it doesn't. And if you don't change that from any to button
但就不是。如果你不把它从 Any 换为 UIButton

662
00:31:58,250 --> 00:32:01,151
the rest of this code is not gonna work. So definitely,
接下来写的代码是用不了的。所以一定

663
00:32:01,220 --> 00:32:04,554
if you remember nothing else from this, remember to change
就算你其他的都记不住，记得

664
00:32:04,623 --> 00:32:07,724
that. All right? So we have this button here and I'm gonna
把类型改了。好吗？所以类型是按钮

665
00:32:07,792 --> 00:32:10,393
hit these other things. But you know, here's obviously,
然后我点……等等，当然

666
00:32:10,462 --> 00:32:12,028
we were sending it to the view controller.
按钮会发消息告诉 ViewController

667
00:32:12,097 --> 00:32:15,231
The event touch up in side just means when you touch
这个 Event，事件是 touch up inside 的意思你

668
00:32:15,300 --> 00:32:17,834
up inside the bounds of the button, send this message.
在按钮的内部点击就调用这个方法

669
00:32:17,902 --> 00:32:20,770
All right, so let's connect. I'm gonna hit Connect.
好，我们点 Connect 来建立关联

670
00:32:20,839 --> 00:32:21,805
It's gonna give me a method.
然后就会创建一个方法

671
00:32:21,874 --> 00:32:25,809
This is your first look at a Swift method right here.
这是你第一次见到 Swift 的方法

672
00:32:25,877 --> 00:32:28,911
And let's look at the parts of it. Interestingly,
让我们来分析它的各个部分。很有趣的是

673
00:32:28,980 --> 00:32:32,482
this is not part of a Swift method, okay. This is just
@IBAction 不是 Swift 方法的一部分，那只是

674
00:32:32,550 --> 00:32:35,719
a special directive that Xcode is putting in there.
Xcode 放在那里修饰方法的特殊指令

675
00:32:35,787 --> 00:32:38,754
That causes it to put this little round circle here where
这样就能让 Xcode 在左边显示一个小圆圈

676
00:32:38,823 --> 00:32:42,759
the line numbers are. You see how line number lucky 13 there
就在显示行号这里。看到这个“幸运”的 13

677
00:32:42,828 --> 00:32:47,030
is a circle instead. If I mouse over that circle,
被换成了个圆圈么？如果我把鼠标移到上面

678
00:32:47,098 --> 00:32:50,333
I'm not clicking just mousing over. If I mouse over that
我没有按下去，只是放在那里。如果我鼠标放上面

679
00:32:50,402 --> 00:32:55,272
it'll show me which buttons send this message,
就会显示是哪些按钮发的消息

680
00:32:55,340 --> 00:32:56,806
which ones invoked this method. So
是哪些会调用这个方法

681
00:32:56,875 --> 00:32:59,375
that's all the IBAction does just cause this circle to
这就是 @IBAction 的作用，就是让圆圈

682
00:32:59,444 --> 00:33:04,447
appear here. Now this is the syntax of a Swift method.
出现在这里。剩下的就是 Swift 方法了

683
00:33:04,516 --> 00:33:05,682
So let's look at it's parts.
让我们来看它的组成部分

684
00:33:05,750 --> 00:33:08,318
Func. It's just a key word that says this is a function.
func，那就是说明这是一个函数（function）的关键字

685
00:33:08,387 --> 00:33:11,121
A method is just a function on a class. It is legal to have
我们知道方法就是定义在类里面的函数。你也可以

686
00:33:11,189 --> 00:33:14,023
functions outside of classes. They're global functions.
在类的外面定义函数，也就是全局函数

687
00:33:14,092 --> 00:33:16,960
We almost never do that cause we're very object oriented,
我们基本不这么做，毕竟是面向对象

688
00:33:17,028 --> 00:33:20,030
but you can do it. This is the name of the method,
但你可以这么做。空格后是方法的名称

689
00:33:20,099 --> 00:33:23,199
touch card. I chose that in the little pop up.
也就是 touchCard，我在之前的小弹窗里决定的

690
00:33:23,268 --> 00:33:26,469
This is a list of all its arguments. Okay,
然后是参数列表

691
00:33:26,538 --> 00:33:31,374
this method has one argument. The type of the argument comes
这个方法有一个参数，参数的类型

692
00:33:31,442 --> 00:33:35,578
at the end with a colon, colon type, which is a UIButton,
是在最后面，用英文冒号隔开——: 类型。这里类型是 UIButton

693
00:33:35,647 --> 00:33:37,981
obviously. We said we wanted one argument,
显然的，我们说我们想要一个参数

694
00:33:38,049 --> 00:33:41,050
which the sender was a UIButton, that's what it is.
也就是类型为 UIButton 的 sender，这就是这个意思

695
00:33:41,119 --> 00:33:46,456
This are the names of this parameter.
然后这些是参数的名称

696
00:33:46,524 --> 00:33:49,725
Names plural. Now, there are two things about Swift that
注意是这些。现在我们讲讲，Swift 有两个

697
00:33:49,794 --> 00:33:51,160
are going to be quite different from what you're
与其他非常不同的地方

698
00:33:51,229 --> 00:33:57,267
used to in other languages. One, every argument has a name
和其他语言不一样，其一是参数有一个实参标签

699
00:33:57,335 --> 00:34:01,771
that you actually include when you call the method. Okay?
你在实际调用方法的时候会用这个标签

700
00:34:01,840 --> 00:34:02,939
So like in Java you would
比如在 Java 里你会用

701
00:34:03,008 --> 00:34:06,342
say touchCard open parenthesis six comma hello
比如 touchCard(6, "hello", 5)

702
00:34:06,411 --> 00:34:08,178
comma five. You would never do that in Swift.
在 Swift 里你不会这样做

703
00:34:08,246 --> 00:34:10,747
Each parameter would have a name in front of
每个实际参数都有一个标签在前面

704
00:34:10,816 --> 00:34:14,384
it. That way if you're calling it and you're reading
这样当你调用了它

705
00:34:14,452 --> 00:34:16,453
the code you don't have to remember that first argument,
你读代码的时候就不需要记住第一个实际参数

706
00:34:16,521 --> 00:34:18,888
what's that again? Because they're each named. And
究竟是什么，因为有标签告诉你

707
00:34:18,957 --> 00:34:21,791
the other thing is it has two names. Okay.
另外一点就是参数有两个名字

708
00:34:21,860 --> 00:34:24,227
The two names are the external name.
其中一个就是之前说的实参标签

709
00:34:24,296 --> 00:34:27,196
That's the name callers use and the internal name. That's
这是调用方法的人用的。另一个是形参名称

710
00:34:27,265 --> 00:34:30,333
the name we're going to use inside of are implementation.
也就是在实现方法的时候使用的形式参数的名称

711
00:34:30,402 --> 00:34:32,768
Now I'm going to write my own method in a second here and
我马上自己写几个方法

712
00:34:32,837 --> 00:34:35,571
we'll talk about this more, but that's what's going on
然后我们再仔细讲讲，但这就是这部分的意思

713
00:34:35,640 --> 00:34:38,808
here. Now if this method had a return value, you show that by
如果这个方法有返回（return）值，你需要

714
00:34:38,877 --> 00:34:42,912
saying arrow Int lets say that would mean this method
通过比如 -> Int 来表示这个方法

715
00:34:42,981 --> 00:34:47,416
returns an Int. Very simple syntax for that. But
会返回 Int 类型的整数。非常简单的语法

716
00:34:47,485 --> 00:34:49,519
this method doesn't return an Int, but you could make it so
但这个方法并不会返回一个整数，但你可以让它

717
00:34:49,587 --> 00:34:53,756
it does. Okay, so let's make sure this is working.
这样做。好，让我们确认下这能用

718
00:34:53,825 --> 00:34:56,926
I'm just gonna use that print function I was talk about this
我就用之前讲的 print 函数

719
00:34:56,995 --> 00:34:59,829
is a global function called print. It just takes a string
print 就是个全局函数。它接受一个字符串参数

720
00:34:59,898 --> 00:35:05,067
and prints on the console. So here I'll print agh! a ghost.
然后打印到控制台里。我输出说这“啊，这是个鬼”

721
00:35:05,136 --> 00:35:07,504
Okay, and we're gonna run our app and
好，运行我们的程序

722
00:35:07,572 --> 00:35:11,407
see if this is working when we press the ghost. So
来看看我们按下这个鬼的时候有没有反应

723
00:35:11,476 --> 00:35:14,311
by the way, when we are gonna print stuff from the console,
顺便一提，当我们要输出到控制台的时候

724
00:35:14,379 --> 00:35:17,047
we probably wanna bring this up from the bottom so
我们最好点这个来显示下面这个面板

725
00:35:17,115 --> 00:35:20,750
we can see our console, we can make our debugger smaller.
这样我们就能看到控制台了。我们把调试器调小点

726
00:35:20,818 --> 00:35:24,287
Here's our console bring it up. There's actually a cool
这就是我们的控制台。其实，很酷的是

727
00:35:24,355 --> 00:35:26,523
thing you can do, I'll show you a Xcode tip.
你还可以这样做。我告诉你个 Xcode 的使用技巧

728
00:35:26,591 --> 00:35:31,194
If you got here to Xcode, Behaviors and Edit Behaviors.
如果你到菜单栏里的 Xcode > Behaviors > Edit Behaviors...

729
00:35:31,262 --> 00:35:33,863
And you go down you can have it so
然后在下面找。你可以让

730
00:35:33,932 --> 00:35:36,299
that Xcode does things, opens windows,
Xcode 做比如新建窗口

731
00:35:36,368 --> 00:35:39,335
does other stuff when certain things happen. For example,
或是在某件事发生的时候做另一件事

732
00:35:39,403 --> 00:35:40,670
if you're running and
比如你运行

733
00:35:40,739 --> 00:35:44,341
it generates some output on the console, you can say
而且会在控制台输出，你可以

734
00:35:44,409 --> 00:35:47,610
show the debugger. Okay, and it will automatically bring
让它显示调试器，Xcode 就会自动

735
00:35:47,679 --> 00:35:49,011
that up from the bottom if it's not there.
把它在下面显示出来

736
00:35:49,080 --> 00:35:51,647
So that's kind of a nice little feature. All right, so
这就是很实用的一个小功能。好

737
00:35:51,716 --> 00:35:55,852
let's run it. Those are the kind of tips and tricks we'll
让我们来运行。像这种使用技巧和提示就是

738
00:35:55,921 --> 00:35:57,787
cover on Friday, by the way. Good reason to come on Friday.
我星期五讲的内容，所以我建议你星期五来

739
00:35:57,856 --> 00:36:00,289
Question, yeah? >> Can you go over again
谁有问题？>> 你能重新演示下

740
00:36:00,358 --> 00:36:05,127
how you link the button to the view controller?
如何把按钮关联到视图控制器的吗？

741
00:36:05,196 --> 00:36:06,295
>> Yeah how we
>> 好的

742
00:36:06,364 --> 00:36:07,897
connect to the button view controller?
我们怎么把按钮关联到视图控制器？

743
00:36:07,966 --> 00:36:09,165
Yeah, I'll show you that in just a second.
好，我等会再演示一遍

744
00:36:09,233 --> 00:36:10,166
So let's make sure it's working and
让我们先确保这可以用了

745
00:36:10,234 --> 00:36:12,168
then I'll show you how we connect to it again. So
然后再展示一下怎么关联的

746
00:36:12,237 --> 00:36:13,036
we have this button here.
我们的按钮显示在这里

747
00:36:13,104 --> 00:36:15,872
I'm gonna click the ghost and look down in our console.
我点一下这个鬼，然后看我们下面的控制台

748
00:36:15,940 --> 00:36:19,576
Look, agh! it's a ghost, okay. So it's working. So
看，输出了 agh! a ghost!。所以是可以用的

749
00:36:19,644 --> 00:36:21,745
we're clicking the button and it's doing that. So
我们按这个按钮，就输出这个句话

750
00:36:21,813 --> 00:36:23,780
the question is, how did we hook it up again?
好，刚才的问题是问如何建立关联

751
00:36:23,849 --> 00:36:26,349
Well what we did is that we held down control, the control
我们做的是我们按住 control 键不放

752
00:36:26,417 --> 00:36:31,087
key, and we dragged from the button into our code.
同时按鼠标，从按钮拖拽出一根线到代码里

753
00:36:31,155 --> 00:36:32,922
And when we let go it asked us all the questions.
然后我们松开鼠标，Xcode 就会问那些问题

754
00:36:32,991 --> 00:36:33,823
What do you want to call it?
比如你要叫它什么名字？

755
00:36:33,891 --> 00:36:37,527
That kind of stuff. All right, so we got this hooked up,
这样的问题。好，我们关联上了

756
00:36:37,596 --> 00:36:40,329
right. Now we need to flip the card over when this happens
现在我们需要把牌反转过来

757
00:36:40,398 --> 00:36:41,797
instead of just saying, agh! a ghost. Okay?
而不只是打印出说这是个鬼

758
00:36:41,866 --> 00:36:44,500
So we're not gonna say agh! a ghost anymore. So
我们不会再打印 "agh! a ghost!" 了

759
00:36:44,569 --> 00:36:48,371
to do that, I'm going to add my own function that flips
要实现这个功能，我要自己写一个函数来翻牌

760
00:36:48,440 --> 00:36:50,973
the card over. So let's create our own Swift function.
让我们来自己写个 Swift 的函数

761
00:36:51,042 --> 00:36:53,643
So we have to say func cuz its a method on a function.
我们用 func 关键字，因为方法也是函数的一种

762
00:36:53,712 --> 00:36:57,580
I'm gonna call this flipCard, okay.
我把它叫做 flipCard，翻牌

763
00:36:57,648 --> 00:36:59,949
And I'm gonna have two arguments.
然后有两个参数

764
00:37:00,018 --> 00:37:04,554
One is the emoji that I want to be on this card,
一个是 emoji，我想要显示在牌上的表情

765
00:37:04,622 --> 00:37:07,290
the ghost or whatever. The other one is the button
比如鬼一类的。另一个参数是按钮

766
00:37:07,358 --> 00:37:10,125
that I want to set the emoji on, or whatever.
我用来显示表情的按钮

767
00:37:10,194 --> 00:37:15,631
So, interestingly here, I'm going to call in these things
很有趣的是，我要取的名字

768
00:37:15,700 --> 00:37:20,003
constrain what you might think are strange names.
你可能会觉得很奇怪

769
00:37:20,071 --> 00:37:25,774
I'm gonna say with emoji, emoji of type string. So
我叫第一个参数 withEmoji emoji: String

770
00:37:25,843 --> 00:37:30,413
this is in external name with emoji internal name emoji. And
实参标签为 withEmoji，形参名称为 emoji，类型是 String 字符串

771
00:37:30,481 --> 00:37:35,985
how about this one on button UIButton. Okay?
然后第二个是 on button: UIButton

772
00:37:36,054 --> 00:37:39,989
Now, these might seem really strange to you as names of
现在看这些，你可能会觉得是很奇怪的

773
00:37:40,058 --> 00:37:42,158
parameters, both internal and external.
参数名，实参标签和形参名称同时出现

774
00:37:42,227 --> 00:37:44,927
And in your reading assignment on the last page, it's gonna
你阅读作业的最后一页会链接到 swift.org 上的

775
00:37:44,996 --> 00:37:47,897
link you to a document you have to read that explains
API Design Guidelines（API 设计准则）

776
00:37:47,966 --> 00:37:50,466
how to pick good names here. Cuz there's a very well
你应该阅读它解释如何挑选好的名字的部分。文档很好地

777
00:37:50,535 --> 00:37:53,203
defined set of rules for picking good names here. But
制定了挑选好名字的规则

778
00:37:53,271 --> 00:37:56,840
the number one rule is when someone calls this function,
但是最重要的是，当有人调用这个函数的时候

779
00:37:56,908 --> 00:38:00,243
it should read like English. That is the number one
应该读起来像普通英语一样。这就是最重要的

780
00:38:00,311 --> 00:38:02,244
requirement of picking these names.
选择名字的要求

781
00:38:02,313 --> 00:38:04,314
So let's call this function in touch card right here,
让我们在 touchCard 里调用这个函数

782
00:38:04,382 --> 00:38:07,216
cuz we want to call it with the ghost. So I'm gonna say
因为我们想要用鬼的表情作为参数，所以我就输入

783
00:38:07,285 --> 00:38:11,020
flipCard. Okay, notice, by the way, as I start to type,
flipCard，注意我开始输入

784
00:38:11,088 --> 00:38:13,823
look at Xcode trying to help me. Xcode's so nice,
Xcode 会想办法帮助我。（没崩溃的）Xcode 多好啊

785
00:38:13,892 --> 00:38:15,791
you see look, it know that I have a flipCard method.
你看看，它知道我有个 flipCard 方法

786
00:38:15,860 --> 00:38:20,530
In fact, I'm just gonna hit tab and it shows me the method
其实如果我按下 tab 键，他就自动补全了方法

787
00:38:20,599 --> 00:38:23,833
with the argument names. And I'm just ready to fill it in.
和实参标签，然后移动到输入实际参数的地方

788
00:38:23,902 --> 00:38:25,935
So this is called, from the caller's point of view,
所以当调用的时候，调用的人所看到的是

789
00:38:26,004 --> 00:38:30,406
flipCard(withEmoji). The emoji is let's say, for
flipCard(withEmoji: 然后是作为参数的表情

790
00:38:30,475 --> 00:38:32,742
example, our ghost. I'll just copy and
比如这里的鬼，我复制粘贴

791
00:38:32,811 --> 00:38:37,981
paste him from right here. On the button and which button?
过来。on，在哪个按钮上操作？

792
00:38:38,049 --> 00:38:41,250
Of course, the sender. That's this sender right here. So
当然是 on: sender)，就是这个形参 sender

793
00:38:41,319 --> 00:38:43,720
you see when I call it, it reads like English.
你看到我调用它的时候，读起来就像英语一样

794
00:38:43,788 --> 00:38:48,091
Flip the card with the emoji ghost on the sender button.
把牌翻过来，显示鬼的表情到发送消息的按钮上

795
00:38:48,159 --> 00:38:50,459
That's our number one thing we're trying to accomplish.
这就是我们要做的第一步

796
00:38:50,528 --> 00:38:53,596
But inside here we wouldn't wanna be saying like, well if
但在 flipCard 里面我们不应该用类似于

797
00:38:53,665 --> 00:38:58,400
the button title equals with emoji that just is weird.
if button.title == withEmoji（如果按钮的标题是使用表情）会很奇怪

798
00:38:58,469 --> 00:39:02,137
It's sending a message to the button that says on.whatever,
或者是用 on.whatever（在上面.无论什么）来调用按钮的方法

799
00:39:02,206 --> 00:39:03,039
that would make no sense,
这都听起来很不正常

800
00:39:03,107 --> 00:39:04,941
so that's why we have these different names.
这就是为什么参数需要两个不同的名字

801
00:39:05,009 --> 00:39:08,811
Now, it is possible and legal to only have one name like
其实是可以，而且完全可以只有一个参数名

802
00:39:08,880 --> 00:39:12,048
just emoji. Then the external internal name would both
比如只有 emoji。这种情况下实参标签和形参名一样

803
00:39:12,116 --> 00:39:17,320
be emoji. And this underbar thing like right here.
都是 emoji。这里的这个英文下划线

804
00:39:17,389 --> 00:39:19,588
That means there's no argument,
意思是没有实参标签

805
00:39:19,657 --> 00:39:20,790
in other words it's just like Java or
也就是像 Java 那样的

806
00:39:20,858 --> 00:39:24,560
some other language. We almost never do that, it is done,
其他语言一样了。我们几乎不会，只有少数时候会这样

807
00:39:24,629 --> 00:39:26,529
the document will tell you when you can do it,
准则里面提到了什么时候你可以或应该这样做

808
00:39:26,597 --> 00:39:29,832
we almost never do it. It's here in this touch card
但基本不会。这里的 touchCard 用了下划线来省略

809
00:39:29,900 --> 00:39:33,069
because that's an iOS thing that's sending this message.
是因为 iOS 系统发来的消息

810
00:39:33,138 --> 00:39:34,637
It's from back in the Objective-C world.
是从 Objective-C 时代就有了

811
00:39:34,706 --> 00:39:38,007
Objective-C doesn't have this internal external name thing.
而 Objective-C 没有这个实参标签的说法

812
00:39:38,075 --> 00:39:40,476
So that's why it's under bar there, okay, but
所以需要有个 _ 来省略参数

813
00:39:40,545 --> 00:39:43,513
we don't really use under bar that much. All right, so
但这并不是很常用

814
00:39:43,582 --> 00:39:45,748
how we're gonna implement this flipCard right here?
那我们怎么实现 flipCard？

815
00:39:45,816 --> 00:39:48,251
Well, this flipCard is essentially gonna toggle it,
flipCard 会把牌翻一个面

816
00:39:48,320 --> 00:39:50,319
and I'm just gonna have this flipCard method,
那么我在 flipCard 方法里

817
00:39:50,388 --> 00:39:53,623
look at the button If it's already the ghost,
判断按钮，看它是否已经显示了鬼了

818
00:39:53,692 --> 00:39:57,393
then I'm gonna have it flip it over to orange with no text.
如果有，那就翻过去，背景色设为橙色，不显示字

819
00:39:57,462 --> 00:40:00,195
If it's not, then I'm gonna put the ghost on it with white
如果没有字的话，那就把鬼显示在白色背景上

820
00:40:00,264 --> 00:40:05,034
background. Just exactly what we played around with earlier.
就像我们之前在白板上玩的一样

821
00:40:05,102 --> 00:40:09,605
So, we need to check to see if the buttons current title
所以我们需要查看按钮目前的标题

822
00:40:09,674 --> 00:40:12,408
is this ghost. So I'm just gonna try and type this in
是否是这个鬼。让我试着输入这段代码

823
00:40:12,476 --> 00:40:15,377
let's see, if the button. Okay, now I need to send
if button，如果按钮……现在我需要

824
00:40:15,446 --> 00:40:19,415
a message to the button asking it what's your current title.
发送消息给按钮问它当前的标题是什么

825
00:40:19,484 --> 00:40:23,386
Well, probably I wanna go look in the documentation, figure
那我应该去查看文档

826
00:40:23,455 --> 00:40:25,788
out what button does. In fact, that's what you want to do.
看看按钮有什么功能。这是最正规的做法

827
00:40:25,856 --> 00:40:28,757
But there's actually a cool way if you just wanna guess
但很酷的是，你可以去猜它叫什么名字

828
00:40:28,826 --> 00:40:32,628
what it is. You can press dot. That's how you send a message
你输入 . 英文句号，也就是 Swift 里发送消息的方法

829
00:40:32,697 --> 00:40:35,831
in Swift to just like Java, right, dot to send a message.
就像 Java 一样，对吧，用点语法来发送消息

830
00:40:35,900 --> 00:40:39,034
And when you do that Xcode is gonna show you all the methods
然后 Xcode 会显示给你所有的方法

831
00:40:39,103 --> 00:40:43,039
and variables that button understands, and let me say,
和变量，这些都是按钮可以接受的。然后我们用

832
00:40:43,107 --> 00:40:46,409
there are quite a few. Okay, I'm scrolling through here,
我看看，不是我说，这里还挺多的

833
00:40:46,478 --> 00:40:48,711
I'm only down to the Cs okay, we got Ds,
我现在还只是在 C 开头的，D 开头的

834
00:40:48,780 --> 00:40:51,447
there's probably a couple hundred. So
可能有好几百个吧

835
00:40:51,515 --> 00:40:53,983
how does this help me? This doesn't help me at all.
所以如何才能用这个帮助我呢？现在这样可没什么用

836
00:40:54,052 --> 00:40:56,885
Well, the cool thing is, if I just type a word here that I
嘛，很酷的是，如果我输入一个词

837
00:40:56,954 --> 00:41:00,223
think might be in the name of the method I want like title.
也就是我猜测的方法的名字，比如我想要 title

838
00:41:00,291 --> 00:41:03,359
I want you to set the title. Now it just shows me things
我想要设置按钮的标题。现在显示的就是

839
00:41:03,428 --> 00:41:06,295
that start with title, or that have title in it, or
以 title 开始的，或者是含有 title 的，或者

840
00:41:06,364 --> 00:41:09,566
have T-I-T-L-E in it, which is not very useful, but
是有字母 T, I, T, L, E 在里面的，虽然这个没什么用

841
00:41:09,634 --> 00:41:12,668
that's why it puts those at the bottom. But anyway,
当然这也就是为什么他们会在下面

842
00:41:12,737 --> 00:41:15,171
we got the title. So now I can start looking around in
总的来说我们有与标题相关的了。现在我可以开始找

843
00:41:15,239 --> 00:41:18,374
a much shorter list here, to see if I can find it.
要找的列表短很多，来看看能不能找到

844
00:41:18,443 --> 00:41:20,909
So here's title color, definitely I don't want that.
这里有 titleColor，标题的颜色不是我想要的

845
00:41:20,978 --> 00:41:24,079
Title rectangle, no. Here's set title.
titleRectangle，不要所在的矩形。这里有 setTitle

846
00:41:24,148 --> 00:41:25,481
I don't wanna set the title right now but
我现在不想要更改标题，但

847
00:41:25,550 --> 00:41:28,350
that's kinda good to know. Look at this one, current
了解这个有好处。看看这个，currentTitle

848
00:41:28,419 --> 00:41:30,919
title. Current title that is displayed on the button.
按钮当前显示的标题

849
00:41:30,988 --> 00:41:34,824
Victory, I found exactly what I want. And when I find what I
赢了呢！这就是我想要的。当我找的了

850
00:41:34,892 --> 00:41:40,730
want here, looks like by the way, returns a string?
我想要的，顺便看看，返回的是 String? 类型

851
00:41:40,798 --> 00:41:42,932
We'll try it anyway. If I double click on it,
管他呢，就用这个了。如果我双击它

852
00:41:43,000 --> 00:41:46,035
it's gonna put that there for me. And now I can just say
Xcode 就会自动补全。如果现在我

853
00:41:46,103 --> 00:41:49,471
is that equal to the emoji that you're asking me to flip
判断是否 == emoji，等于你让我翻过去显示的表情

854
00:41:49,540 --> 00:41:52,975
the card to. This first argument. Notice how I'm using
emoji 就是我们的第一个参数。注意我用的是

855
00:41:53,044 --> 00:41:56,846
emoji and button as my internal names here.
emoji 和 button 来作为方法内部使用的名称

856
00:41:56,914 --> 00:42:00,483
I'm not using with emoji or on. That was for the caller.
而不是 withEmoji 或者 on；那是调用的时候使用的

857
00:42:00,552 --> 00:42:05,020
Okay, so now I found out that the button already here
好，现在我知道了如果按钮

858
00:42:05,089 --> 00:42:07,957
has the ghost on it. So now I wanna make it orange and
已经有鬼的表情在上面了，那就把背景色设为橙色

859
00:42:08,026 --> 00:42:10,927
blank. So now I need to set the button's title, and I saw
然后不显示字。如果我想要设置按钮的标题

860
00:42:10,995 --> 00:42:14,997
before that it was set title. Here it is, set title. Now
我之前看到了有 setTitle 可以实现，所以调用 setTitle

861
00:42:15,066 --> 00:42:18,501
this set title has extra thing here, for UI control state.
setTitle 还有一个参数，for: UIControlState

862
00:42:18,570 --> 00:42:21,336
You see that? It's like, what the heck is that?
看到了吗？你会想，那是什么鬼？

863
00:42:21,405 --> 00:42:24,439
I don't know anything about buttons, so, I'm not sure.
我并不了解按钮，所以我不清楚那是什么

864
00:42:24,508 --> 00:42:27,109
But I don't see any other set title, so I guess I'll have to
但并没有其他类似于 setTitle 的了，那估计

865
00:42:27,178 --> 00:42:30,713
go with this one. Okay, so I double click on it. The title
我只能用这个了。好，我双击它

866
00:42:30,782 --> 00:42:34,183
I want to set here, of course, is empty string because,
我想要设的标题当然是空字符串

867
00:42:34,251 --> 00:42:36,018
I'm trying to do the back of the card here.
因为我想显示卡牌的背面

868
00:42:36,087 --> 00:42:39,789
So I empty it out. And now I'm kind of at this control state
也就是把字清空。然后是这个 UIControlState

869
00:42:39,858 --> 00:42:43,125
impasse, because I don't really know what this means.
陷入僵局了，我不知道那是什么意思

870
00:42:43,194 --> 00:42:45,795
So, here's another cool thing you can do,
这时，我们可以做的另一件很酷的事情是

871
00:42:45,863 --> 00:42:48,564
is hold down option and mouse over anything,
按住 option 键不放，然后把鼠标移动到上面

872
00:42:48,633 --> 00:42:52,234
you see how it's highlighting things with a little question
看到那部分会被高亮，然后鼠标变为一个

873
00:42:52,303 --> 00:42:55,704
mark right there? And you can click on it and it'll show you
问号了吗？你可以点击它，然后就会显示

874
00:42:55,773 --> 00:42:59,174
the documentation for that thing. So here is set title,
那个东西的文档。所以这是 setTitle

875
00:42:59,243 --> 00:43:01,410
the documentation for it. And if I read through this,
这个方法的文档。如果我读了这个

876
00:43:01,479 --> 00:43:03,579
the third paragraph and description says,
第三段的描述说

877
00:43:03,648 --> 00:43:05,648
at a minimum, you should set the value for
至少你需要设置 normal 状态下的标题

878
00:43:05,717 --> 00:43:10,419
the normal state. Okay, sounds good. Now I'd like to
也就是普通状态的标题。好，听起来不错

879
00:43:10,488 --> 00:43:13,489
understand how to get that normal state, so I'm gonna
现在我想知道如何得到那个普通状态

880
00:43:13,558 --> 00:43:17,393
actually click on this link here, you see UIControlState?
所以我点击这个链接，看到 UIControlState 是个链接了吗？

881
00:43:17,462 --> 00:43:19,428
And it's gonna take me to the documentation and
它会带我到文档里

882
00:43:19,497 --> 00:43:22,598
show me control state. So here we go, click brings up
给我展示 UIControlState 的信息。我点下去

883
00:43:22,667 --> 00:43:26,269
the documentation, here's control state, see that? And
文档就出来了，UIControlState，看到了吗？

884
00:43:26,337 --> 00:43:30,139
here it is normal, the very first one is called normal.
这里是 normal，第一个就是普通状态

885
00:43:30,208 --> 00:43:33,242
And we're gonna see later how we use these things but
等会儿我们会看到怎么使用这些

886
00:43:33,310 --> 00:43:35,778
this is a static, you see it's a static var.
但是这里有 static，这是静态变量

887
00:43:35,847 --> 00:43:39,115
So it's kind of a property of the type, and so
就像是属于类型的属性

888
00:43:39,183 --> 00:43:42,185
the way that we will type that in is to say,
所以我们输入这个的方法是

889
00:43:42,253 --> 00:43:45,454
UIControlState.normal. So it's awesome, we found that, but
UIControlState.normal。很好，我们找到了普通状态

890
00:43:45,523 --> 00:43:46,622
while I'm here in the documentation,
但当我还在文档里的时候

891
00:43:46,691 --> 00:43:49,525
let me briefly show you how the documentation works.
让我简单介绍一下文档是怎么用的

892
00:43:49,594 --> 00:43:52,361
Right here, you can see that I'm looking in UI kits
这里说我们看的是 UIKit

893
00:43:52,430 --> 00:43:55,798
at its views and controls at the class UIControl, which
视图（view）和控件（control）

894
00:43:55,867 --> 00:43:59,068
button inherits from. And we're looking at this thing,
也就是按钮继承的父类所在的地方，然后我们看的是

895
00:43:59,136 --> 00:44:01,604
UIControlState. But I can click anywhere here and
UIControlState，控件的状态。但我可以随便点击

896
00:44:01,672 --> 00:44:05,241
go back and maybe look at UIButton if I want. And here's
如果我想的话，比如回去看看 UIButton，然后这就是

897
00:44:05,309 --> 00:44:07,843
UIButton. Now, when you're looking at the documentation,
UIButton 的文档。当你看文档的时候

898
00:44:07,912 --> 00:44:11,246
I super strongly recommend you read these overview sections.
我强烈建议你读读概述的部分

899
00:44:11,315 --> 00:44:12,948
You see where this says Overview?
看到这里写着是 Overview 了吗？

900
00:44:13,017 --> 00:44:15,585
This overview section in each class,
每个类的概述

901
00:44:15,653 --> 00:44:17,787
only take you five minutes to read. And it's really
只需要大概五分钟的阅读时间，但是非常有用

902
00:44:17,855 --> 00:44:20,690
gonna help you understand what the heck is going on here.
能帮助你理解这都是些什么东西

903
00:44:20,759 --> 00:44:22,491
So, I strongly recommend you do that for
所以我强烈建议你这样做

904
00:44:22,559 --> 00:44:25,094
all the common classes that you're using, UIButton later
所有你用到的常有的类，比如 UIButton

905
00:44:25,162 --> 00:44:27,563
we're gonna do array in dictionary. Go read it so
之后的 Array（数组）和 Dictionary（字典），去读读

906
00:44:27,632 --> 00:44:31,601
you understand what the heck is going on in here. Got that?
这样你就理解这些内容了。清楚了吗？

907
00:44:33,104 --> 00:44:35,470
You can also search the documentation of course here.
当然你还可以直接在这里搜索文档

908
00:44:35,539 --> 00:44:38,474
And in addition to overview it has a list of all the methods.
除了概述之外还有方法列表

909
00:44:38,542 --> 00:44:39,541
And here, for example,
比如说这里

910
00:44:39,610 --> 00:44:42,711
here is set title again. Go back and see if it's the same
这是 setTitle 方法，然后点进去还是一样的内容

911
00:44:42,780 --> 00:44:47,049
that shows up in that little box. So now we know that this
和那个小弹窗里的文档一样。所以现在我们知道

912
00:44:47,118 --> 00:44:49,852
control state here is supposed too be UIControlState.normal.
这里控件的状态应该是 UIControlState.normal

913
00:44:49,920 --> 00:44:53,522
It's gonna set the normal control state. We also want to
他会设置普通状态下的标题。我们还想

914
00:44:53,591 --> 00:44:56,359
set the background color so I'm going to do button dot and
设置背景颜色，所以我用 button.

915
00:44:56,427 --> 00:44:58,827
I'm gonna just take a flyer, backgroundcolor.
我就碰碰运气，backgroundColor，背景色

916
00:44:58,896 --> 00:45:02,198
Sure enough, look backgroundColor or something,
没错，还真有 backgroundColor

917
00:45:02,267 --> 00:45:05,768
exactly called backgroundColor that takes a UI color,
就叫做 backgroundColor，类型是 UIColor?

918
00:45:05,837 --> 00:45:08,470
I think? Let's double click that one. And
难道不是吗？让我们双击这个

919
00:45:08,539 --> 00:45:11,607
I'm gonna set that equal to, believe it or not you can
然后赋值为，不管你信不信，你可以

920
00:45:11,676 --> 00:45:14,409
actually put a color literal in here. You just
直接放一个颜色在这里

921
00:45:14,478 --> 00:45:16,946
do that by starting to type the word color, and you're
你只需要输入 color，然后你看

922
00:45:17,014 --> 00:45:19,148
gonna see the first choice is always Color Literal.
第一个选项 Color Literal 就是字面值颜色

923
00:45:19,217 --> 00:45:20,649
If you double click on that,
如果我双击它

924
00:45:20,718 --> 00:45:22,518
it puts a little square in here.
Xcode 就会放一个小方框在这里

925
00:45:22,587 --> 00:45:25,021
If you click on the square you can pick the color you want.
你可以点击这个方框，然后选择一个你想要的颜色

926
00:45:26,257 --> 00:45:27,823
So let's go back and pick our nice orange,
我们就选这个很不错的橙色

927
00:45:27,892 --> 00:45:29,425
cuz that's what we do in the background.
因为这就是我们想要的背景色

928
00:45:29,493 --> 00:45:33,029
And so, we've set our background color to orange.
所以我们就把背景色设为橙色了

929
00:45:33,097 --> 00:45:34,931
And it's really nice to be able to see that in your code.
能在代码里看到实际的颜色是很棒的功能

930
00:45:34,999 --> 00:45:38,100
It really highlights the colors you're using.
能够凸显出你想用的具体是什么颜色

931
00:45:38,168 --> 00:45:41,304
All right otherwise if it's not, doesn't have the ghost
好，那如果没有显示鬼这个表情的话

932
00:45:41,372 --> 00:45:43,105
right now then we want to put the ghost on there.
那我们就把鬼显示出来

933
00:45:43,173 --> 00:45:45,942
So I'm gonna do pretty much exactly the same code here.
我用的基本上是同样的代码

934
00:45:46,010 --> 00:45:48,311
It's just that I'm gonna set the title instead of blank,
还是 setTitle，只不过不是空字符串

935
00:45:48,379 --> 00:45:51,180
like the background. I'm gonna set it to the emoji,
也就是上面的那样，而是设为 emoji

936
00:45:51,249 --> 00:45:54,316
the ghost in this case. And I'm gonna double click on this
这种情况下是鬼的表情。然后我双击

937
00:45:54,385 --> 00:45:57,186
orange square and change it to white, because I want a white
这个橙色的方块，然后改成白色的，因为我想要

938
00:45:57,254 --> 00:46:01,890
background for the front. We got that? Okay,
卡前面是白色背景。看懂了吗？好

939
00:46:01,959 --> 00:46:04,393
let's run, see if our card. Our card should flip over now,
让我们再来运行看看我们的卡片。我们的卡片应该可以翻过来了

940
00:46:04,461 --> 00:46:08,531
which is getting us quite a long way along the path here
虽然我们花了点功夫才实现

941
00:46:08,600 --> 00:46:11,400
to getting concentration working. Right here is
才能玩这个翻牌游戏。这里是

942
00:46:11,469 --> 00:46:16,272
our ghost. Cross your fingers. Whoo, it flips over and
我们的鬼表情。上帝保佑，我要点了。哇哦！翻过去了

943
00:46:16,340 --> 00:46:20,876
back. Okay, excellent. All right, we're on a roll.
很好，我们成功了

944
00:46:20,945 --> 00:46:21,677
Now, let's go and
现在让我们

945
00:46:21,746 --> 00:46:24,613
add another card. Okay, we got one card. Let's go to
添加另外一张卡。这是我们现在的一张卡

946
00:46:24,682 --> 00:46:27,416
the second card. Believe it or not, you can take things in
然后第二张卡，不管你信不信，你可以选择这张卡

947
00:46:27,484 --> 00:46:29,518
Interface Builder that are the way you want it and
选中 Interface Builder 里的这个

948
00:46:29,587 --> 00:46:32,020
just copy and paste them. So now I have two cards and
然后复制粘贴。现在我有了两张卡

949
00:46:32,089 --> 00:46:34,690
this card already is the right shape that I want,
这张卡的形状已经是我想要的了

950
00:46:34,758 --> 00:46:37,259
it's got the right font size all that stuff.
字体大小等也都没有问题

951
00:46:37,328 --> 00:46:40,129
So it's really recommended to copy and paste verses dragging
所以我建议你复制粘贴，而不是

952
00:46:40,198 --> 00:46:42,297
out a new one and trying to set it to all the same thing.
重新拉出来一个，然后尝试修改为一摸一样的

953
00:46:42,366 --> 00:46:44,599
Just copy and paste.
你就复制粘贴就好

954
00:46:44,668 --> 00:46:48,103
Now this one wants a different thing on it, so let's do
但是这个上面的表情应该是不一样的，让我们用

955
00:46:48,172 --> 00:46:52,942
something like pumpkin. Yeah, well we could do a pump and
比如说南瓜怎么样？好，我们可以

956
00:46:53,011 --> 00:46:55,978
now we'll do pumpkin, all right? So we got pumpkin.
我们就用南瓜

957
00:46:56,047 --> 00:46:58,180
So we had pumpkin card and we got a ghost card.
我们有了南瓜卡和鬼卡

958
00:46:58,249 --> 00:47:00,983
Now this pumpkin card, it needs a method.
现在这个南瓜卡需要一个方法

959
00:47:01,051 --> 00:47:04,353
So we're gonna Ctrl+drag to create another method.
所以我们按住 control 拖拽来创建另一个方法

960
00:47:04,422 --> 00:47:06,722
So if you missed it the first time, this is how we do it.
如果你第一次没记住，我再来演示下怎么做

961
00:47:06,791 --> 00:47:10,660
It's an action. I'm gonna call this touchSecondCard.
选择 Action，操作方法，叫做 touchSecondCard

962
00:47:13,531 --> 00:47:17,967
The type, of course, we want a UI button, argument sender.
类型，当然选 UIButton，Argument 是 Sender 作为参数

963
00:47:18,035 --> 00:47:20,903
Connect it, here it is. I'm gonna take this
Connect 来关联它。然后我就把

964
00:47:20,971 --> 00:47:24,339
exact same code from here, put it down here,
这段代码复制粘贴过来

965
00:47:24,408 --> 00:47:28,578
but instead of the ghost right here, I'm gonna use our pumpkin.
但是不是鬼的表情，而是用这个南瓜

966
00:47:31,616 --> 00:47:34,984
Okay, looks good, right? This could not possibly go wrong,
好，很好，是吧？这个可能有问题

967
00:47:35,052 --> 00:47:40,089
this is so simple. It's gotta work,
非常简单，应该可以用

968
00:47:40,158 --> 00:47:45,427
okay, let's do it. All right, here we go,
好，让我们来运行试试

969
00:47:45,496 --> 00:47:50,666
the ghost still working like a charm. And a Pumpkin, pumpkin
鬼这个没有问题。然后南瓜，南瓜，南瓜

970
00:47:50,734 --> 00:47:54,136
not working. Okay, what is wrong with our pumpkin?
并没有用。那南瓜这个有什么问题呢？

971
00:47:54,204 --> 00:47:57,806
How could this pumpkin possibly not be right. Well,
这个换成了南瓜怎么就不行了呢？

972
00:47:57,875 --> 00:48:00,342
we could get in the debugger here, set a breakpoint,
那让我们把调试器显示出来，是一个断点（breakpoint）

973
00:48:00,411 --> 00:48:02,577
it's real easy to set a breakpoint by the way.
顺便说下设置断点很容易

974
00:48:02,646 --> 00:48:04,179
You just click on a line number,
只需要点击行号就可以了

975
00:48:04,248 --> 00:48:06,782
puts the breakpoint there. But
就会在那里设一个断点

976
00:48:06,851 --> 00:48:08,951
we're gonna do a little more lightweight debugging.
但我这会儿用个更简单的调试方法

977
00:48:09,020 --> 00:48:12,320
I'm just going to put a print here in flipCard, to see if
我就在 flipCard 里加一个 print 来看

978
00:48:12,389 --> 00:48:15,390
this is even calling flipCard. It should be calling flipCard,
它是否调用了 flipCard。应该是会调用的

979
00:48:15,459 --> 00:48:18,427
because it's connected here to this method, so it should be
因为它关联了这个方法，所以应该

980
00:48:18,495 --> 00:48:20,562
calling flipCard. So I'm just gonna go in here and
调用 flipCard 方法了的。所以我在这里

981
00:48:20,631 --> 00:48:25,401
say print, that I'm in flipCard withEmoji. And
用 print 函数说我在 "flipCard(withEmoji: 里

982
00:48:25,470 --> 00:48:28,437
now I wanna put this emoji in here. Now,
现在我想要把这个 emoji 表情加到这里

983
00:48:28,506 --> 00:48:32,174
in a lot of other languages, you would probably say %s,
在其他的语言里，你可能会用 %s

984
00:48:32,243 --> 00:48:34,943
comma, emoji, or something like that, right?
%s)", emoji 之类的，是吧？

985
00:48:35,012 --> 00:48:39,849
This would be your, oops, this would be your string.
然后这就是你的字符串

986
00:48:39,917 --> 00:48:43,819
But we don't have this %s business in Swift,
但是 Swift 里不会和 %s 一类的打交道

987
00:48:43,887 --> 00:48:48,457
we have something better, which is\(). So
我们用更好的 \() 来实现字符串插值

988
00:48:48,526 --> 00:48:53,362
\() means put something inside there, it's gonna interpret it
\() 可以让我们在括号里放一些东西，然后把它

989
00:48:53,431 --> 00:48:57,099
as a string, and embed it in this string. So that's exactly
作为一个字符串插入到这个字符串里。这就是

990
00:48:57,168 --> 00:49:00,369
what we want, emoji, and the cool thing about it is,
我们想要的，把 emoji 放进去。更酷的是

991
00:49:00,438 --> 00:49:03,105
I could put, this is a string, so it's easy to embed.
虽然我这里 emoji 是字符串，插入到字符串里并不难

992
00:49:03,174 --> 00:49:06,107
But I could put an Int here, anything that can be converted
但是我还可以放一个整数在这里，任何能转化

993
00:49:06,176 --> 00:49:08,844
to a string, which most things in Swift can, I can put there,
为字符串的都可以，也就是说 Swift 里大部分的我都能放进去

994
00:49:08,913 --> 00:49:11,380
I can even put an array there, or a dictionary.
我设置可以放个数组或是字典在这里

995
00:49:11,449 --> 00:49:13,482
As long as the array only had things that could
当然前提是数组里的内容要能够

996
00:49:13,550 --> 00:49:15,717
be converted to a string, then it can convert the whole
用字符串来表示，那它就会把整个都转换

997
00:49:15,786 --> 00:49:20,122
array to a string. So this is a really cool feature,
把数组变成字符串。这是个很厉害的特性

998
00:49:20,191 --> 00:49:24,459
this\(), all right? So let's run again, and
能用 \() 实现字符串插值。让我们再次运行

999
00:49:24,528 --> 00:49:30,232
see if that pumpkin is calling flipCard, which it should be.
然后看看南瓜卡是否按照预期调用了 flipCard

1000
00:49:30,301 --> 00:49:33,202
All right, so the ghost, it's definitely calling it,
好，鬼卡，肯定是调用了的

1001
00:49:33,271 --> 00:49:36,705
see flipCard withEmoji, the ghost, how about the pumpkin?
看这个 flipCard(withEmoji: 鬼表情)，那南瓜呢？

1002
00:49:36,774 --> 00:49:40,442
It looks like it's calling it, but I didn't press that twice,
看起来是调用了的，但是我并没有按两下

1003
00:49:40,511 --> 00:49:43,245
what's going on there? That that's kinda weird,
但为什么多了两行呢？这有点奇怪

1004
00:49:43,314 --> 00:49:49,752
let's do it again. No look at that, it's doing both.
让我们再试试。看看，它两个表情都有

1005
00:49:49,821 --> 00:49:51,186
Every time I press the pumpkin,
每次我按下南瓜

1006
00:49:51,255 --> 00:49:53,088
it's doing the ghost and the pumpkin, ghost and
同时会出现鬼和南瓜，鬼和南瓜

1007
00:49:53,157 --> 00:49:55,657
pumpkin. Why is it doing it twice, okay,
为什么会调用两次呢？

1008
00:49:55,726 --> 00:49:58,460
that's clearly they're messing things up badly.
我们肯定是搞砸了

1009
00:49:58,529 --> 00:50:02,798
Well, let's look and see why it's doing that. We know that
让我们来看看为什么会变成这样。我们知道

1010
00:50:02,867 --> 00:50:06,168
this method is being called by the pumpkin. And
touchSecondCard 被南瓜卡调用了

1011
00:50:06,236 --> 00:50:12,307
this method is being called by both. that's the problem.
touchCard 被两张卡都调用了，这就是问题所在

1012
00:50:12,376 --> 00:50:15,878
And why did that happen, cuz I copied and pasted the ghost.
为什么会这样呢？因为我复制粘贴了鬼

1013
00:50:15,947 --> 00:50:17,946
And when I copied and pasted the ghost, it copied and
当我复制粘贴鬼的时候，他还复制

1014
00:50:18,015 --> 00:50:20,682
pasted the fact that it was sending that message. So
粘贴了它要发送的消息

1015
00:50:20,751 --> 00:50:22,384
this is a common mistake to make,
这是很容易犯的错误

1016
00:50:22,453 --> 00:50:25,287
really easy. So I did it intentionally to show you how
非常容易，所以我故意错给你看

1017
00:50:25,355 --> 00:50:28,957
to get out of this, which is to right-click on something.
教你如何解决这个问题——那就是右键点击

1018
00:50:29,026 --> 00:50:31,794
If you right-click on anything in the UI, it will show you
如果你右键点击 Interface Builder 里的东西，就会显示

1019
00:50:31,862 --> 00:50:35,764
all the connections that it has. So this is the pumpkin,
它所有的关联。所以这个是南瓜卡的关联

1020
00:50:35,833 --> 00:50:38,567
it's sending touchCard and touchSecondCard, but
它会调用 touchCard 和 touchSecondCard

1021
00:50:38,635 --> 00:50:40,969
we only want it to send touchSecondCard. So
但我们只想要它调用 touchSecondCard

1022
00:50:41,038 --> 00:50:45,340
I'm gonna disconnect touchCard by clicking right here.
所以我要通过点这个叉来取消关联

1023
00:50:45,409 --> 00:50:49,711
Now I fixed it, okay, now the pumpkin is sending this,
现在我解决了问题，南瓜卡只会发这一个消息

1024
00:50:49,780 --> 00:50:54,082
and only the ghost is sending this. So right-click is
而这个方法也只有鬼卡会调用。所以右键

1025
00:50:54,151 --> 00:50:57,218
an important thing to know, if you ever get in a situation
非常重要的，你需要了解。如果你遇到的

1026
00:50:57,287 --> 00:50:58,387
where it seems like,
那种情况你觉得是

1027
00:50:58,456 --> 00:51:01,223
I thought I wired that up, why is it not sending it?
你应该关联了却没有发送消息

1028
00:51:01,291 --> 00:51:04,292
Or even why is it crashing trying to send something that
或者是尝试发送消息的时候意外崩溃

1029
00:51:04,361 --> 00:51:06,962
I didn't intend? Right-click on it, will tell you why.
那就右键点击看看是什么原因

1030
00:51:07,030 --> 00:51:11,333
So let's run, see if that indeed fixed our problem here,
让我们再来运行看看是否解决了我们这里的问题

1031
00:51:11,402 --> 00:51:17,873
I imagine it will. Okay, it's got the ghost flipping over,
我觉得已经可以了。好，鬼卡翻过去了

1032
00:51:17,941 --> 00:51:21,176
we got the pumpkin flipping over, okay, excellent,
我们让南瓜卡也翻过去，很好

1033
00:51:21,245 --> 00:51:25,680
all going great. Now before I add yet more cards, I want to
一切正常。但在我加另外一张卡之前，我想要

1034
00:51:25,749 --> 00:51:29,584
have some UI that tells me how many times I've flipped cards.
在界面里显示我翻过了多少张牌

1035
00:51:29,653 --> 00:51:31,420
Because you notice in this game,
因为注意这个游戏

1036
00:51:31,488 --> 00:51:34,823
the fewer times I flip it, the better I am at it, right?
翻牌的次数越少，我就算是玩的越好，对吧？

1037
00:51:34,892 --> 00:51:36,158
If I flipped them all over, up and down,
如果我挨个都翻过了，翻过去翻过来

1038
00:51:36,227 --> 00:51:37,826
up and down, then I'm not very good, it's easy,
翻过去翻过来，那可不好，太简单了

1039
00:51:37,895 --> 00:51:40,395
I didn't have to concentrate. So I wanna have some UI that
我并不需要集中注意力，所以我希望界面

1040
00:51:40,464 --> 00:51:44,266
says how many times I've flipped a card, okay? So to do
能够显示我翻了多少张卡了

1041
00:51:44,335 --> 00:51:46,769
that I'm gonna start, let's get rid of this print in here,
那开始，我先把 print 删掉

1042
00:51:46,837 --> 00:51:49,537
we don't need that debugging anymore. So I'm gonna
我们不需要继续调试了

1043
00:51:49,606 --> 00:51:52,674
start by adding an instance variable to my class that
我在类里添加一个实例变量

1044
00:51:52,743 --> 00:51:56,679
keeps track of the flip count, okay, real, real simple like.
来记录翻了多少次，非常简单

1045
00:51:56,747 --> 00:51:59,782
Move this down here so we can get some space, all right?
让我打几个回车来腾点空间

1046
00:51:59,850 --> 00:52:04,018
So what does it look like to add an instance variable to
那如何才能够在类里面添加实例变量呢？

1047
00:52:04,087 --> 00:52:09,058
your class? Really simple, you use the keyword var, short for
非常简单，用关键字 var

1048
00:52:09,126 --> 00:52:13,962
variable. Then the name flipCount, then the type,
变量 variable 的缩写，然后名字是 flipCount

1049
00:52:14,030 --> 00:52:18,967
: Int, that's it. So I have added here a variable called
然后 : Int 说明这是整数。就这样，我就添加了一个变量

1050
00:52:19,036 --> 00:52:22,804
flipCount to my class, and I'm gonna keep that flipCount up
我的类里有了叫做 flipCount 的变量，然后

1051
00:52:22,873 --> 00:52:25,640
to date as these cards are flipped on. But,
每翻一次牌就更新 更新 flipCount

1052
00:52:25,709 --> 00:52:30,579
look what happened here, I had an error. So this red, when
但是看看发生了什么，提示有个错误。所以这个红色的

1053
00:52:30,648 --> 00:52:34,382
you have a red error, your app won't even compile and run.
当你看到红色的错误，你的程序不能编译，也不能运行

1054
00:52:34,451 --> 00:52:37,352
You can also get a yellow one, then your app will compile and
你还可能遇到黄色的警告，你的程序能编译

1055
00:52:37,421 --> 00:52:40,021
run, but do not submit your homework with yellow ones
能运行，但你交的作业两个都不能有

1056
00:52:40,090 --> 00:52:42,258
either. Even though they're just warnings,
即使只是警告

1057
00:52:42,326 --> 00:52:44,393
they are usually indicator something bad, so
但那说明肯定有问题

1058
00:52:44,461 --> 00:52:47,963
don't do that either. But this red, I gotta fix this red.
所以不能有警告。但这个是红色的，我必须解决这个错误

1059
00:52:48,032 --> 00:52:50,932
Now what's funny is this red came up on a different line of
但有趣的是红色的这一条出现在另一行

1060
00:52:51,001 --> 00:52:54,503
code. I typed this line of code in, and it came up on
我输入的是这一行代码，但是出现在

1061
00:52:54,572 --> 00:52:56,972
a completely different line. Well what does this say here,
完全不同的一行。那说的是什么呢？

1062
00:52:57,040 --> 00:53:00,809
it says, class ViewController has no initializers.
它说 ViewController 类没有构造器（initializer）

1063
00:53:00,878 --> 00:53:03,645
Why is it saying that, what does that have to do with it?
为什么会这么说呢？这和我这行代码有什么关系？

1064
00:53:03,714 --> 00:53:07,049
Well, this is happening because Swift requires
其实原因是 Swift 要求

1065
00:53:07,117 --> 00:53:09,651
all instance variables, which by the way in Swift,
所有的实例变量，顺便一提 Swift

1066
00:53:09,720 --> 00:53:11,920
we call instance variables properties.
把实例变量叫做属性（property)

1067
00:53:11,989 --> 00:53:13,355
So when you hear me saying property,
所以当你听到我用 property 属性

1068
00:53:13,424 --> 00:53:17,125
I mean instance variable. So all instance variables,
我指的就是实例变量。Swift 要求所有实例变量

1069
00:53:17,194 --> 00:53:19,394
all properties have to be initialized,
所有属性都要初始化

1070
00:53:19,463 --> 00:53:22,831
you are not allowed to have them like this flipCount int.
你不能只是写 flipCount: Int

1071
00:53:22,899 --> 00:53:25,867
What is the value right now? It has no value, okay,
flipCount 的值是多少？没有值

1072
00:53:25,936 --> 00:53:27,769
it has to have an initial value,
所以必须要有初始值

1073
00:53:27,838 --> 00:53:30,472
it's just not allowed to be sitting out there. Now there's
不能够就只定义就完了

1074
00:53:30,540 --> 00:53:33,242
two ways to initialize an instance variable,
有两种办法可以初始化实例变量

1075
00:53:33,310 --> 00:53:36,411
one is using an initializer. So that's what this error is
其一是使用构造器，这就是这个错误

1076
00:53:36,480 --> 00:53:39,982
trying to tell us, get an initializer here, dude.
想要告诉我们的，写个构造器

1077
00:53:40,050 --> 00:53:42,851
An initializer is just this method with a special name,
构造器就是个特殊的方法，有一个特殊的名字

1078
00:53:42,920 --> 00:53:45,087
init, short for initializer, and
init，initializer 的缩写

1079
00:53:45,155 --> 00:53:46,688
it can have any arguments you want. In fact,
可以有任何类型和数量的参数。事实上

1080
00:53:46,757 --> 00:53:49,758
you can have multiple inits, each with different arguments.
你还可以有多个构造器，每个的参数不一样

1081
00:53:49,826 --> 00:53:52,661
But each init is responsible for initializing
但是每一个构造器都要负责初始化

1082
00:53:52,730 --> 00:53:56,931
all of the variables, okay, that's what the init's job is.
所有的实例变量，这就是构造器的作用

1083
00:53:57,000 --> 00:53:59,801
So we could add an initializer here and do that.
所以我们可以添加一个构造器

1084
00:53:59,870 --> 00:54:02,904
Now, unfortunately, adding an initializer to a class can be
但是给一个类添加构造器

1085
00:54:02,973 --> 00:54:05,574
kinda complicated because of inheritance, right?
可能会因为继承而变得复杂，对吧？

1086
00:54:05,643 --> 00:54:07,176
Because your superclass has initializers,
因为你的父类有构造器

1087
00:54:07,244 --> 00:54:09,244
you gotta make sure they get called properly.
你需要确保正确调用它们

1088
00:54:09,312 --> 00:54:11,113
So I'm not even gonna talk about initializers yet, okay,
所以我先不讲构造器

1089
00:54:11,181 --> 00:54:13,682
I'll talk a little bit about them on Wednesday. Next week
我星期三会多讲一些。下一周

1090
00:54:13,750 --> 00:54:16,051
we'll really talk more in depth about initializers. And
我们会更深入地讲解构造器。同时

1091
00:54:16,120 --> 00:54:18,120
so what's the second way that I can initialize this,
我们还有第二种方法初始化它

1092
00:54:18,189 --> 00:54:19,855
since I don't wanna do initializers right now?
毕竟我不想用构造器

1093
00:54:19,924 --> 00:54:24,392
And that's just right here to say, = 0, okay,
这个方法就是用 = 0 来赋值为零

1094
00:54:24,461 --> 00:54:28,797
if I just, why do I keep pressing v there, okay,
为啥我打了个 v，应该是空格

1095
00:54:28,866 --> 00:54:31,533
Int = 0, okay. That initializes this,
好，: Int = 0，就能初始化了

1096
00:54:31,602 --> 00:54:34,369
that's gonna cause this error to go away, all is well. And
这样错误就消失了

1097
00:54:34,437 --> 00:54:38,673
this is how we initialize most of our instance variables.
这也是我们大部分时间用来初始化实例变量的方法

1098
00:54:38,742 --> 00:54:41,210
Now while I'm here, talking about instance variables,
既然我讲到了这里，让我继续讲讲实例变量

1099
00:54:41,278 --> 00:54:44,379
I wanna talk a little bit about Swift and typing.
我想多讲讲 Swift 和类型

1100
00:54:44,448 --> 00:54:48,217
Swift is an extremely strongly typed language,
Swift 是个非常强类型的语言

1101
00:54:48,285 --> 00:54:52,421
I mean extreme. It does have a type which is kind of like
极端的强类型。虽然有类型代表

1102
00:54:52,489 --> 00:54:54,489
untyped, but really it's mostly for
没有类型，但那是为了

1103
00:54:54,558 --> 00:54:57,959
backwards compatibility with Objective-C. In most cases you
向后兼容 Objective-C。大部分时候

1104
00:54:58,028 --> 00:55:01,629
want to be very specific about what types you're using,
你应该明确你用的是什么类型

1105
00:55:01,698 --> 00:55:05,234
and some people complain about strongly typed languages. It's
有些人会因此抱怨强类型语言

1106
00:55:05,302 --> 00:55:08,170
so much burden to always be typing something. Okay, well
主要是觉得总是要输入类型太恼火了。所以

1107
00:55:08,238 --> 00:55:12,574
Swift is also a language that has strong type inference,
Swift 同时还有强大的类型推导

1108
00:55:12,643 --> 00:55:17,445
which means it will, if it can, guess the type for you.
也就是能够帮你猜出类型是什么

1109
00:55:17,514 --> 00:55:20,282
So in this case, you see I have this : Int type,
比如这个地方，我用了 : Int 来声明类型

1110
00:55:20,350 --> 00:55:22,417
that is completely unnecessary in Swift. And
这在 Swift 里是完全没有必要的

1111
00:55:22,486 --> 00:55:25,020
not only unnecessary, we would not put it in there, there is
而且不仅是不必要，我们根本就不会放在那里

1112
00:55:25,089 --> 00:55:28,957
no reason to put that there. Why is that, because this 0 is
根本没有理由放在那里。为什么？因为这个 0

1113
00:55:29,026 --> 00:55:33,895
clearly an Int. Swift treats all literals like this,
说明了它就是整数。Swift 对于所有的字面值都是这样处理的

1114
00:55:33,964 --> 00:55:36,898
that don't have any decimal points as Ints. And
这个没有小数点，所以是 Int 类型

1115
00:55:36,967 --> 00:55:39,400
so this is an Int, and how do we know that? If we hold down
我们如何确认这是 Int 类型呢？我们按住

1116
00:55:39,469 --> 00:55:42,070
Option, just like we did when we clicked on Title down here
option 键不放，然后就像我们点击 setTitle 一样

1117
00:55:42,138 --> 00:55:44,973
to get the documentation, we can click on flipCount, and
我们点击 flipCount 就可以得到文档

1118
00:55:45,042 --> 00:55:49,144
it'll say flipCount is an Int. You see that, and if I
然后它说 flipCount 是整数类型的，看到了吧

1119
00:55:49,213 --> 00:55:53,649
had said flipCount was 0.0, then if I hold down option and
如果我说 flipCount = 0.0，我再按住 option 键

1120
00:55:53,717 --> 00:55:57,385
go back here to flipCount, it says flipCount is a double,
点击 flipCount，就会说他是 Double 双精度小数

1121
00:55:57,454 --> 00:56:00,221
okay? So into, it infers it, if I said flipCount equals
所以它能推测出来。如果 flipCard = "hello"

1122
00:56:00,290 --> 00:56:03,191
"hello", it's going to say okay,
那它就会说

1123
00:56:03,260 --> 00:56:06,995
flipCount is a string All right, so it's gonna infer.
flipCount 是个字符串。所以 Swift 能推导出类型

1124
00:56:07,064 --> 00:56:09,965
Now, this is easy to infer cause this is a constant but
可以说因为它是常量，所以很容易推测

1125
00:56:10,034 --> 00:56:13,668
swift can even infer in the most amazing complicated
但是 Swift 甚至能在非常复杂的情况下

1126
00:56:13,737 --> 00:56:16,838
situations. If there's only one type that thing can be,
推测类型。如果只可能是一种类型的话

1127
00:56:16,907 --> 00:56:17,772
it'll make it that type and
Swift 就认为它是那个类型

1128
00:56:17,841 --> 00:56:18,573
you don't have to put the types.
你不需要声明类型

1129
00:56:18,642 --> 00:56:22,811
So it's surprising in Swift. The time you put types in
这是 Swift 很惊人的一点。你输入类型最多的

1130
00:56:22,880 --> 00:56:26,414
the most is arguments to functions. Because that you
是声明函数参数的类型，因为

1131
00:56:26,483 --> 00:56:28,650
kind of have to say what, what you're expecting there. But
你必须交代你期待的是什么类型

1132
00:56:28,719 --> 00:56:30,953
otherwise you rarely are actually putting the types.
其他情况下你都基本不用声明类型的

1133
00:56:31,021 --> 00:56:33,755
It's quite amazing, actually. All right, so we have this
这还挺神奇的。好，我们有了

1134
00:56:33,824 --> 00:56:36,257
flip count here. Let's go ahead and increment it. K,
这里的 flipCount 来计数，我们这就来增加它

1135
00:56:36,326 --> 00:56:39,127
every time someone steps, presses on a card I'm gonna
每次有人点了一张卡

1136
00:56:39,195 --> 00:56:43,131
say flip count plus equals one and ug I'm gonna copy and
我就 flipCount += 1 来增加一

1137
00:56:43,200 --> 00:56:45,900
paste the code. God. Anytime you're copying and
然后我复制粘贴代码。天呐。每次你

1138
00:56:45,969 --> 00:56:47,936
pasting code, you're doing it wrong.
复制粘贴，那就是做错了

1139
00:56:48,004 --> 00:56:51,005
Okay, that can't be right. So I just did something that's
不应该是这样的，即使我做了不该做的事

1140
00:56:51,074 --> 00:56:53,608
not right but I'm doing it anyway. I could probably put
但我还是要这样。我应该可以

1141
00:56:53,677 --> 00:56:55,943
that somewhere else but I'm gonna just.
把它放到其他地方，但是我就

1142
00:56:56,012 --> 00:56:58,112
We'll do it this way for now. You'll see why in a second and
我们现在就这样了。你等会就知道为什么了

1143
00:56:58,181 --> 00:57:00,548
we'll fix it. But we don't want to complicate the code.
然后我们再来解决它，总之我们不想有复杂的代码

1144
00:57:00,617 --> 00:57:02,017
But each time a card is touched,
总之每次点击一张卡片

1145
00:57:02,085 --> 00:57:05,120
I'm gonna increment the flip count. Now that's great, but
我就增加 flipCount。这很好，但是

1146
00:57:05,189 --> 00:57:06,855
I need this flip count to appear in the UI,
我需要在界面上显示翻的次数

1147
00:57:06,923 --> 00:57:09,891
okay. I want the user to see how many flips they've made.
我希望用户看到他们翻了多少次

1148
00:57:09,960 --> 00:57:11,260
So I have to have this int
所以我需要有这个整数

1149
00:57:11,328 --> 00:57:13,428
appear in the UI. So how do I do that? Well,
出现在用户界面里。我怎么做呢？

1150
00:57:13,496 --> 00:57:17,265
I need some sort of other UI element besides a button And
我需要不是按钮的 UI 控件

1151
00:57:17,334 --> 00:57:19,467
that's just a little text field. Okay, in fact there's
它只是一个标签显示些文字。那么事实上

1152
00:57:19,536 --> 00:57:23,438
a read-only text field which is called the UILabel in iOS.
iOS 里只读的文本框叫做 UILabel

1153
00:57:23,507 --> 00:57:26,207
And so of course anytime we wanna add something to UI,
所以每当我们想往 UI 里添加标签的时候

1154
00:57:26,276 --> 00:57:29,945
I go here, to the bottom side, in fact right next to button,
我到右边，下面这里，就在按钮旁边

1155
00:57:30,013 --> 00:57:33,181
here is label. I'll drag it out and put it in here.
标签就是这个 Label。我把它拖出来放到这里

1156
00:57:33,250 --> 00:57:36,651
I'll try and center it or something like that.
我会尝试把它放在中间，就像这样

1157
00:57:36,720 --> 00:57:39,454
It's really really small so I'm gonna make it much bigger
现在它太小了，我要把它拉宽一点

1158
00:57:39,523 --> 00:57:42,090
cuz I'm gonna be using big font in a second here.
因为等会儿要选一个大一点的字号

1159
00:57:42,159 --> 00:57:46,728
Even make it taller. The text is black so
然后拉高一点。因为现在字是黑色的

1160
00:57:46,796 --> 00:57:49,398
it's black on black. That's a little hard to see so
黑底黑字，所以很难看见字

1161
00:57:49,466 --> 00:57:52,767
I'm gonna go back over to here, go to the top half here,
然我回到这里，右边的上半部分

1162
00:57:52,836 --> 00:57:54,669
change the color of the text, okay,
更改字的颜色

1163
00:57:54,738 --> 00:57:57,905
which is a label property right here. From this,
也就是标签的一个属性，在这里

1164
00:57:57,974 --> 00:58:02,644
to our favorite color, orange. This text is really small, so
把它改为我们最喜欢的颜色，橙色。这个字很小，所以

1165
00:58:02,713 --> 00:58:04,445
I'm going to change the font from 17pt,
我要把字从 17 点

1166
00:58:04,514 --> 00:58:07,482
which is the default here, to something like 40.
也就是默认值，改为 40

1167
00:58:07,551 --> 00:58:10,318
Much better. I don't want it to say label here,
这下好了。还有我不想要它显示 label

1168
00:58:10,387 --> 00:58:13,655
I want it to say Flips, let's say we'll start out Flips: 0.
我想让它显示翻了多少次，那一开始就是 Flips: 0

1169
00:58:13,723 --> 00:58:17,058
I don't want it left-aligned like that, okay,
我不希望是左对齐

1170
00:58:17,127 --> 00:58:18,159
I don't want the text left-aligned,
我不希望字都靠在左边

1171
00:58:18,228 --> 00:58:20,828
I want it in the center, so I go over here and hit center.
我希望他们能居中，所以我在这里选择居中

1172
00:58:20,897 --> 00:58:24,065
So see how I'm just using this editing inspecting up here to
所以我只用了这个检查器来编辑

1173
00:58:24,134 --> 00:58:26,701
kinda get the thing to look the way I want it to look.
让它看起来像我想要的那样

1174
00:58:26,770 --> 00:58:29,971
I can even use my dashed blue lines here to
我还可以用这些蓝色的虚线做参考

1175
00:58:30,040 --> 00:58:33,208
put it right along the bottom and right in the center. Okay.
把它放到下面的正中央

1176
00:58:33,276 --> 00:58:35,010
Even though I said we are not really using those,
虽然我说我们并没有真正用上参考线

1177
00:58:35,078 --> 00:58:36,278
it's still useful to do that one.
但还是有意义的

1178
00:58:36,346 --> 00:58:38,279
All right, so
好

1179
00:58:38,348 --> 00:58:41,916
now I have my UI, how do I talk to it? How do I tell it
现在我的 UI 构建好了，我怎么和它沟通呢？我如何告诉他

1180
00:58:41,985 --> 00:58:45,120
when the flips change to show the flips? Well, I'm gonna
当翻的次数改变了之后就更新显示新的翻的次数？

1181
00:58:45,189 --> 00:58:48,389
do that also by making connections between my UI and
我可以通过关联 UI 到代码来实现这个

1182
00:58:48,458 --> 00:58:53,228
my code. And we know how to do that, Ctrl drag Right?
我们是知道要怎么做的，按住 control 拖拽，对吧？

1183
00:58:53,296 --> 00:58:56,331
Ctrl+Drag, put it right here. And this time,
按 control，拖到这里来。这一次

1184
00:58:56,400 --> 00:58:59,400
though, I'm not doing an action, I'm doing an outlet.
我不会选 Action，我要选 Outlet，出口

1185
00:58:59,469 --> 00:59:02,404
And what an outlet does is it creates an instance variable.
出口就是创建一个实例变量

1186
00:59:03,874 --> 00:59:05,841
So action creates a method,
所以 action 创建一个方法

1187
00:59:05,909 --> 00:59:08,242
Outlet creates an instance variable or property and
outlet 出口创建一个实例变量，也就是属性

1188
00:59:08,311 --> 00:59:11,212
that property is gonna point to this UI label and
那个属性会指向这个 UILabel

1189
00:59:11,281 --> 00:59:12,347
I'll be able to talk to it and
这样我就能跟他交流

1190
00:59:12,416 --> 00:59:15,617
tell it to update itself when the flips change. All right,
告诉它翻的次数改变了就更新

1191
00:59:15,686 --> 00:59:19,387
so what am I gonna call the name of this thing, I'll
那我给他取个什么名字好呢？

1192
00:59:19,456 --> 00:59:22,957
call this my flipCountLabel, it got the type right here
我叫它 flipCountLabel。这次类型是对了

1193
00:59:23,026 --> 00:59:25,927
didn't see any. Don't worry about this storage week.
并不是 Any。现在不用管 strong 和 weak

1194
00:59:25,996 --> 00:59:28,163
I'm gonna talk about that next week. And so
这个我下周讲

1195
00:59:28,231 --> 00:59:30,898
I'm gonna hit connect and it's gonna create another var.
现在我点击 Connect，它就创建了另一个变量

1196
00:59:30,967 --> 00:59:33,668
Like var flipCount. But this var is gonna be a little
就像 var flipCount 一样，但这个会有些不一样

1197
00:59:33,737 --> 00:59:38,874
different. This var is, sorry wrong place there.
这个变量，啊，点错地方了

1198
00:59:38,943 --> 00:59:44,078
This var is var flipCountLabel: UILabel!
这个是 var flipCountLabel: UILabel!

1199
00:59:44,147 --> 00:59:48,649
Okay? Now you can't infer this type by the way because
这个你不能推测类型

1200
00:59:48,718 --> 00:59:51,919
that UILabel is in the UI. So Swift doesn't know how to look in
因为这个 UILabel 是在用户界面上的。Swift 不知道

1201
00:59:51,988 --> 00:59:54,556
the UI and infer a label so it can't infer that there.
如何看着你的界面设计就推导出你这是个 UILabel，做不到的

1202
00:59:54,625 --> 00:59:58,259
So we do need to explicitly say it to UI label here. Week,
所以这里我们需要明确说明是 UILabel

1203
00:59:58,328 --> 01:00:01,129
I told you to look, we'll tell you next week.
weak 就像我说的，下周讲

1204
01:00:01,198 --> 01:00:05,200
This is another kind of directive like this one that
@IBOutlet 也是一个修饰变量的特殊指令，就像 @IBAction 一样

1205
01:00:05,268 --> 01:00:08,170
puts the little dot there so that we can see that's that,
在这里放了一个小圆圈，看到这个和这个关联

1206
01:00:08,238 --> 01:00:11,673
that's that, that's that. Okay, so here's the var,
这两个是关联的，这两个也是。好，回到我们这里的变量

1207
01:00:11,742 --> 01:00:13,841
exactly the same as we did with flip count.
就像我们的 flipCount 一样

1208
01:00:13,910 --> 01:00:17,011
Notice there's a little exclamation point there. That
注意我们这后面有感叹号

1209
01:00:17,080 --> 01:00:20,448
is super important. But I'm not gonna talk about it today.
这非常重要，但我今天不会讲

1210
01:00:20,517 --> 01:00:23,919
I can't talk about everything all at once. Notice that this
我不能一次把所有内容都讲完。注意这个

1211
01:00:23,987 --> 01:00:26,487
very important thing also has a side effect.
非常重要的感叹号是有副作用的

1212
01:00:26,556 --> 01:00:27,889
It's not the primary purpose of it but
虽然并不是它存在的主要目的

1213
01:00:27,958 --> 01:00:31,025
the side effect is. It doesn't have to be initialized.
但是副作用是，如果 flipCountLabel 没有初始化

1214
01:00:31,094 --> 01:00:33,694
notice this doesn't say equals anything and yet
注意它还没有被赋初值

1215
01:00:33,763 --> 01:00:36,798
we don't have an error. Okay? So don't freak out about that.
但我们并没有得到任何错误。你们不用为此担心

1216
01:00:36,867 --> 01:00:38,566
I'm gonna talk all about this exclamation point.
我会讲关于感叹号的内容的

1217
01:00:38,635 --> 01:00:40,135
It could not be more important,
没有比这更重要的了

1218
01:00:40,203 --> 01:00:42,170
probably the most important newish
可能是最重要的

1219
01:00:42,238 --> 01:00:44,873
thing that you're going to learn about Swift, okay,
你需要学习的关于 Swift 的新知识

1220
01:00:44,942 --> 01:00:48,243
is what its all about. All right, so I got this flip
这就是这段代码的意思。好，我有了

1221
01:00:48,311 --> 01:00:50,278
count label right here. Now, all I want to do is,
这里的 flipCountLabel，我想要的是

1222
01:00:50,347 --> 01:00:53,047
every time this flip count changes, like, right here.
每次 flipCount 改变了，比如这里

1223
01:00:53,116 --> 01:00:56,818
I'm going to talk to the flip count label and I want to set
我想要告诉 flipCountLabel 说

1224
01:00:56,887 --> 01:01:00,488
it's text, label. I want to set it's text, so I'm going to
我想要改变它显示的字，设置这个 flipCountLabel 的字

1225
01:01:00,557 --> 01:01:03,257
send it a message and I want to set text, so I'm just going
所以给它发消息说我想设置显示的字

1226
01:01:03,326 --> 01:01:05,760
to say text. There happens to be something called text,
那就是 text，正好有叫 text 的属性

1227
01:01:05,829 --> 01:01:07,062
the very first one there. You see that?
第一个就是，看到了吗？

1228
01:01:07,130 --> 01:01:09,864
It says text as a string, so I'm going to double click on
它说 text 是个字符串，所以我双击

1229
01:01:09,933 --> 01:01:15,236
that All right and I'm gonna set that text to, Flips:,
好，我把字赋值为 "Flips: "

1230
01:01:15,305 --> 01:01:18,940
and then I'm gonna use my favorite feature right here,
然后我要用我最喜欢的特性

1231
01:01:19,008 --> 01:01:22,344
\(). And I'm gonna put the flipCount in there. So
\(flipCount) 来插入翻牌的次数到这里

1232
01:01:23,780 --> 01:01:26,881
that's gonna change the text on this flipCountLabel here,
所以这就会更改 flipCountLabel 显示的字

1233
01:01:26,950 --> 01:01:30,284
and we'll see Flips: 1, so it's going to whatever And
我们就能看到 Flips: 1，然后一直加下去

1234
01:01:30,353 --> 01:01:34,088
of course, I have to copy and paste again right
当然，我需要复制粘贴一份

1235
01:01:34,157 --> 01:01:38,126
there because I need to update it each time. So,
因为每次更改 flipCount 都要更新

1236
01:01:38,195 --> 01:01:42,864
let's see if
让我们看看

1237
01:01:42,933 --> 01:01:47,635
this works.
这能不能用

1238
01:01:47,704 --> 01:01:50,639
Okay, here we go. Let's try to flipping this card. Ooh, yeah.
好，出来了，我们试试翻这张卡，好

1239
01:01:50,707 --> 01:01:53,175
Everytime we flipped over our back.
每次我们翻的时候

1240
01:01:53,243 --> 01:01:57,078
It's incrementing the flip count. Okay, fantastic.
它就会把 flipCount 计数器加一。很好

1241
01:01:57,147 --> 01:02:01,650
Except this really is nasty. I just copy and pasted.
除了我们的代码很糟糕都好。我只是在复制粘贴

1242
01:02:01,718 --> 01:02:04,219
I mean, imagine I really was doing it this way and
假设我就这样做

1243
01:02:04,288 --> 01:02:06,154
I had another button called New Game and
然后有了另一个按钮，叫做 newGame

1244
01:02:06,223 --> 01:02:08,222
I had to set the flip count back to zero.
开始新游戏要把 flipCount 重置为零

1245
01:02:08,291 --> 01:02:10,625
I'm going to have to put this same line of code there to.
我需要把同样的代码放在那里

1246
01:02:10,693 --> 01:02:12,360
And what if some day I said, well,
然后如果我有一天决定

1247
01:02:12,429 --> 01:02:14,796
I don't want this to say flip, I want it to say flip count.
我不想要它显示 Flips，我想显示 Flip Count

1248
01:02:14,865 --> 01:02:16,698
Now I've got to change it all three places.
那我三个地方全都要改

1249
01:02:16,767 --> 01:02:18,733
This is just horrendous coding.
这简直是糟糕透了的代码

1250
01:02:18,801 --> 01:02:21,803
Luckily, in Swift, there is a way to avoid doing this in
幸好 Swift 有一种方法能避免这个

1251
01:02:21,871 --> 01:02:25,707
this case, which is that any property, if you want,
如果你想的话，任何的属性

1252
01:02:25,775 --> 01:02:30,678
you can put code after it that says, did set. And it will
都可以放代码在后面的 didSet 里

1253
01:02:30,747 --> 01:02:35,716
execute this code every time that thing gets set. Okay?
每次那个变量的值发生改变之后，这些代码就会运行

1254
01:02:35,785 --> 01:02:38,720
That's called a property observer. Because this code is
这叫做属性观察器，因为这些代码

1255
01:02:38,789 --> 01:02:43,224
observing changes of this. So we can take this outta here,
会观察这个变量的改变。所以我们把这些代码拿出来

1256
01:02:43,293 --> 01:02:46,294
put it up here, and we can take it away from here now.
放到上面这里，我们就可以把它从这里删掉了

1257
01:02:46,362 --> 01:02:50,565
Every time flip count changes, it's going to Execute that
每次 flipCount 改变之后，就会运行

1258
01:02:50,633 --> 01:02:54,235
didSet, and talk to the label, and update it.
didSet 里的代码，然后告诉标签让它更新文字

1259
01:02:54,303 --> 01:02:56,637
So now if I add a new game and set flip count equals zero,
如果我添加个 newGame 设 flipCount 为零

1260
01:02:56,706 --> 01:03:01,743
it would automatically update it.
他也会自动更新

1261
01:03:01,811 --> 01:03:03,278
Property observer is really cool.
属性观察期非常厉害

1262
01:03:03,346 --> 01:03:07,048
Obviously we use property observers a lot to keep the UI
显然我们会经常用属性观察器来让 UI

1263
01:03:07,117 --> 01:03:10,351
in sync with the instance variables of our class. Okay,
和我们类里的实例变量保持同步

1264
01:03:10,420 --> 01:03:14,455
so you'll see that happening all the time. All right, time
你总是会看到他们。好

1265
01:03:14,524 --> 01:03:18,826
to get more buttons. We got these two buttons. By the way,
让我们多加一些按钮。我们有这两个按钮

1266
01:03:18,895 --> 01:03:23,698
notice that we're driving our UI from the code, right?
注意我们应该是用代码来驱动用户界面的

1267
01:03:23,767 --> 01:03:26,100
It's this line of code that's saying what's in the UI.
这一行代码决定了界面上显示什么

1268
01:03:26,169 --> 01:03:28,603
So I'm actually gonna change these two buttons to be
所以我让这两个按钮改为

1269
01:03:28,671 --> 01:03:29,771
face down.
面朝下

1270
01:03:29,840 --> 01:03:32,306
Okay when they start. And what's interesting is if I
一开始的时候是这样的。注意有趣的是

1271
01:03:32,375 --> 01:03:35,810
select them both, and go over to the top here of this thing,
如果我两个同时选中，到右边上面这里

1272
01:03:35,879 --> 01:03:38,980
notice it notices they're both buttons. So
注意他们都是按钮

1273
01:03:39,049 --> 01:03:41,582
I can change things, like here it says multiple values for
所以我可以更改，比如说这里的目前有多个值

1274
01:03:41,651 --> 01:03:43,651
the text, ghost and the pumpkin.
的文字属性，鬼和南瓜

1275
01:03:43,720 --> 01:03:46,487
I can set that to blank, and I can go down to the bottom and
我可以都设为空白，我可以到下面

1276
01:03:46,556 --> 01:03:50,825
set the background color here to orange And it's affecting
把背景色改为橙色，于是同时更改了

1277
01:03:50,894 --> 01:03:52,627
both of them. So if you select multiple things,
这两个。所以如果你有很多个东西

1278
01:03:52,696 --> 01:03:55,529
as long as they're of the same, they share the same
只要他们是同一类型的

1279
01:03:55,598 --> 01:03:59,267
type, then you can edit them all simultaneously.
你就可以所有的一起编辑

1280
01:03:59,335 --> 01:04:01,603
Okay. So I have these cards, let's make some more cards.
好，我有了这些卡，让我来创造更多的卡

1281
01:04:01,671 --> 01:04:04,472
I'm going to copy and paste these cards. Actually,
我复制粘贴这些卡，但事实上

1282
01:04:04,540 --> 01:04:06,341
before I do that, let's do one other thing.
在那之前，我们先做另一件事

1283
01:04:06,410 --> 01:04:11,679
I'm pretty unhappy with my architecture here,
我很不喜欢我这里的架构

1284
01:04:11,747 --> 01:04:14,949
because if I wanna add more cards I guess I'm gonna have
因为如果我添加更多的卡片的话我需要

1285
01:04:15,018 --> 01:04:19,120
to do copy, touch third card, fourth card, fifth card,
复制粘贴出按下第三张，第四张，第五张卡

1286
01:04:19,188 --> 01:04:21,122
sixth card, seventh card, eight card, nine, okay.
第六张，第七张，第八张，第九张的方法

1287
01:04:21,191 --> 01:04:23,991
That is gonna be the worst code, you would get an F on
那就会成为很糟糕的代码了，然后你的作业会是不及格

1288
01:04:24,060 --> 01:04:27,461
your homework if you did that. That's just awful, so we're
如果你的代码是那样的话，那太差劲了

1289
01:04:27,530 --> 01:04:30,631
clearly not gonna use that architecture to do that and
所以明显我们不会用这种结构来实现

1290
01:04:30,700 --> 01:04:33,568
in fact I want to get rid of this touch second card
其实我也想删掉 touchSecondCard 方法

1291
01:04:33,637 --> 01:04:36,137
entirely, and I just want to put everything in touch card.
完全删掉，然后所有的都放到 touchCard 里

1292
01:04:36,205 --> 01:04:38,773
And that means I won't have this line of code duplicated
这就是说我不用重复这一行代码

1293
01:04:38,842 --> 01:04:40,007
and this line of code duplicated.
和这一行代码

1294
01:04:40,076 --> 01:04:42,944
This is gonna be great. This is much better, UI.
这样就很好，好多了

1295
01:04:43,013 --> 01:04:45,780
So to do this I'm gonna right click on this one and
那要这样做，我需要右键点击它

1296
01:04:45,849 --> 01:04:49,951
disconnect touch second card and instead have this guy
取消关联 touchSecondCard，取而代之

1297
01:04:50,019 --> 01:04:54,022
ctrl-drag to here. Look at that you can hook it up to one
按 control 拖拽到 touchCard 方法。看，你可以关联

1298
01:04:54,091 --> 01:04:56,090
that already exist by just dragging to it and
已经存在的方法，只需要按 control 拖拽过去

1299
01:04:56,159 --> 01:05:00,929
letting go. So now both of these are sending touchCard.
然后在方法上松开。现在两个按钮都发送给 touchCard

1300
01:05:00,998 --> 01:05:03,731
Okay, so that's great but inside here we
很好，但是在这里面

1301
01:05:03,800 --> 01:05:07,101
obviously can't do this. Have this ghost thing here,
显然我们不能这么做，用这个鬼作为参数

1302
01:05:07,170 --> 01:05:09,904
because then it would set both cards to ghost. So how are we
因为两张卡都会被设为鬼，那我们

1303
01:05:09,973 --> 01:05:12,674
gonna have code in here in touch card, that works for
怎么样让 touchCard 里面的代码适用于

1304
01:05:12,742 --> 01:05:16,344
all the cards? Well what I'm gonna do is I'm gonna create
所有的卡片呢？我要做的是我会创建

1305
01:05:16,413 --> 01:05:20,381
an array of all these cards and when touchCard is pressed,
一个这些卡片的数组，当按下去之后 touchCard 被调用了

1306
01:05:20,450 --> 01:05:23,151
I'm gonna look in that array, find the button that's being
我就在数组里面找，找到那个被按下的按钮

1307
01:05:23,220 --> 01:05:26,320
pressed, and then I'll know which card it is. Then, when I
然后我就知道是哪张卡片了

1308
01:05:26,389 --> 01:05:28,355
know which card it is, which index it is in the array.
既然我知道了是哪张卡，知道了它的索引（index）

1309
01:05:28,424 --> 01:05:32,526
I'm going to lookup in another array, the emoji to put there.
我就到另一个数组里去找到对应的表情显示出来

1310
01:05:32,595 --> 01:05:34,796
So, it's going to be data driven. Right, and so
也就是由数据驱动。好

1311
01:05:34,865 --> 01:05:35,730
if I want to add more cards,
我想要添加更多的卡

1312
01:05:35,799 --> 01:05:38,332
I just add more cards to my emoji array.
就只用往两个数组里加更多的卡就行了

1313
01:05:38,401 --> 01:05:39,868
It's going to be great. All right, so
这样程序会变得很好

1314
01:05:39,936 --> 01:05:42,003
let's make more cards. I'm going to copy and
让我们来加上更多的卡，复制

1315
01:05:42,071 --> 01:05:45,339
paste to make more cards, so I have four cards and
粘贴出更多的卡，现在我有了四张

1316
01:05:45,408 --> 01:05:49,744
now I wanna make an array that includes these cards, okay.
现在我想要一个包含这四张卡的数组

1317
01:05:49,812 --> 01:05:51,546
So how do I do an array that include these cards?
那我怎么创建一个包含这些卡的数组呢？

1318
01:05:51,614 --> 01:05:53,647
Well, that's a connection between the UI and the codes.
嘛，这需要关联用户界面和代码

1319
01:05:53,716 --> 01:06:00,087
So I'm gonna control, drag and create another var right here.
所以我按住 control 拖拽过来创建另一个变量

1320
01:06:00,156 --> 01:06:03,458
Okay, but this one's gonna be the third kind which is outlet
但是这个我们选第三中类型，outlet collection

1321
01:06:03,527 --> 01:06:07,095
collection. So now outlet collection means an array
出口集合就是一个数组

1322
01:06:07,163 --> 01:06:10,398
of the things in the UI. So I'll call this my cardButtons,
里面是些 UI 控件。我把数组叫做 cardButtons

1323
01:06:10,466 --> 01:06:13,234
I'm actually gonna make a mistake, okay and
等等，我要来故意犯个错，少个 t

1324
01:06:13,303 --> 01:06:15,869
say card butons instead of buttons,
叫他 cardButons 而不是 Buttons

1325
01:06:15,938 --> 01:06:18,606
because I want to show you how to fix this mistake if you do.
因为我想像你展示你遇到这种问题怎么解决

1326
01:06:18,674 --> 01:06:21,609
And it's got the type right, this is gonna be an array of
类型是正确的，UIButton 数组

1327
01:06:21,677 --> 01:06:24,979
UI button. Okay, so I'm gonna connect it right here and
然后点 Connect 建立关联

1328
01:06:25,048 --> 01:06:26,947
it created another var for me right here.
然后就创建了另一个变量

1329
01:06:27,016 --> 01:06:31,119
This one and look at its type. See that right there. That is
就这个。看看它的类型，[UIButton]

1330
01:06:31,187 --> 01:06:35,856
special syntax in Swift that means an array of UI button.
Swift 里表示数组的特殊语法，这是一个 UIButton 数组

1331
01:06:35,925 --> 01:06:39,393
This might look more familiar if I use another Swift syntax,
如果我用另一种 Swift 语法表示数组，你估计会更熟悉

1332
01:06:39,462 --> 01:06:44,732
array of UI button, that look familiar to
Array<UIButton>，这个看起来像 Java 里

1333
01:06:44,801 --> 01:06:49,537
you from Java, right? So array is a generic class, everyone
声明数组的语法吧？所以数组是泛型（generic）

1334
01:06:49,606 --> 01:06:52,806
know about generics in Java, hopefully. It means that
希望大家都知道 Java 里的泛型，意思是

1335
01:06:52,875 --> 01:06:56,577
you can't have the class array on its own be a type in Swift,
数组的元素可以是 Swift 里任何的类型

1336
01:06:56,646 --> 01:06:59,814
because I told you Swift is very strict about types.
因为我告诉过你 Swift 对类型很严格

1337
01:06:59,882 --> 01:07:02,250
So when you are putting things in and out of that array,
所以当你从数组里存取的时候

1338
01:07:02,319 --> 01:07:04,185
Swift would have a heart attack if it
如果它不知道你要把什么类型的值放进去的话

1339
01:07:04,254 --> 01:07:06,754
didn't know the type of thing you're putting in there. So
那 Swift 会吓个半死

1340
01:07:06,822 --> 01:07:09,556
when you create an array you have to specify what type of
所以你创建数组的时候要声明

1341
01:07:09,625 --> 01:07:13,361
thing is in the array so that Swift can breathe easy, okay.
数组元素的类型，这样 Swift 才能正常工作

1342
01:07:13,429 --> 01:07:16,698
Now arrays are so common that instead of using this
因为数组的是很常用的，所以与其用

1343
01:07:16,766 --> 01:07:20,134
normal Swift, this is normal Swift syntax right here, but
这个普通的 Array<元素类型> 语法

1344
01:07:20,203 --> 01:07:23,738
for arrays, we do this special thing here, where
我们实际是用特殊的 [元素类型] 语法

1345
01:07:23,806 --> 01:07:27,809
we say [UIButton]. It's just for arrays that we do this,
比如这个 [UIButton]。这个只是数组的特殊语法

1346
01:07:27,877 --> 01:07:29,544
dictionaries also have a special one, I'll show you
字典我们有另外的语法。我会给你看

1347
01:07:29,612 --> 01:07:32,813
that on Wednesday. Okay? So that's our array,
就星期三的时候吧？好，这是我们的数组

1348
01:07:32,882 --> 01:07:36,417
CardButons is array, now I have this cardButons here
现在我有了这个 cardButons 数组

1349
01:07:36,486 --> 01:07:39,253
okay, and this is connected to that one card, I haven't put
它和那一张卡关联上了，我还没有

1350
01:07:39,322 --> 01:07:42,156
the other cards in there yet but I will. It's connected to.
关联到其他的卡上，但我之后会的

1351
01:07:42,225 --> 01:07:44,425
Now what if I decided no, I don't want Butons,
现在我决定我不想要 Butons 少个 t

1352
01:07:44,494 --> 01:07:47,128
I made a mistake, it's Buttons and remember I told you,
我犯错了，其实是 Buttons。还记得我告诉你

1353
01:07:47,196 --> 01:07:50,898
you don't wanna edit things in here then also in the UI,
你不能只是更改代码，你需要同时更改 UI

1354
01:07:50,967 --> 01:07:53,534
okay like the name of the class and things like that.
比如要修改类的名称一类的

1355
01:07:53,603 --> 01:07:56,871
Well if you do that look what happened to the little circle.
如果你只改了代码，看看这个圆圈

1356
01:07:56,940 --> 01:07:59,540
Okay it doesn't have a dot in it anymore because
圆圈里的点没了

1357
01:07:59,609 --> 01:08:01,208
it's not connected anymore.
因为没有关联了

1358
01:08:01,277 --> 01:08:04,545
Because this, if I right click on it, it's connected to
因为我右键它，显示的是

1359
01:08:04,614 --> 01:08:08,716
Card Butons there, okay? It's not connected to Card Buttons.
关联的 cardButons 而不是 cardButtons

1360
01:08:08,785 --> 01:08:12,486
So, how can I fix this? If I said this Card Butons,
怎么解决这个问题呢？如果我改回 cardButons

1361
01:08:12,555 --> 01:08:14,188
okay it's back to being connected now and
它就又关联上了

1362
01:08:14,257 --> 01:08:17,125
I want to change this. It's another magic key.
但我想改名字。还有个神奇的按键

1363
01:08:17,193 --> 01:08:20,161
The command key. We all ready showed you the alt key for
command 键。我们已经展示了 alt/option 键

1364
01:08:20,230 --> 01:08:21,195
getting into the documentation.
可以显示文档

1365
01:08:21,264 --> 01:08:23,831
If you command click on something, k,
如果你按住 command 再点击

1366
01:08:23,900 --> 01:08:26,600
like this cardButons right here.
比如这个 cardButons

1367
01:08:26,669 --> 01:08:29,637
You get another kind of menu here that'll do some cool
你会得到另一个可以干很酷的事情的菜单

1368
01:08:29,705 --> 01:08:31,939
things like jump to the definition of this thing,
比如这里的 Jump to Definition 可以跳转到定义它的地方

1369
01:08:32,008 --> 01:08:33,040
which happens to be right here so
正好就是这一行

1370
01:08:33,109 --> 01:08:35,043
that's not gonna go anywhere. Show quick help,
所以并不会去其他地方。Show Quick Help

1371
01:08:35,111 --> 01:08:39,680
just like the option one does, and also rename and
会像按 option 键一样给文档。还可以重命名

1372
01:08:39,749 --> 01:08:42,216
when I click rename here, look at what happens.
我点这个 Rename，看看发生了什么

1373
01:08:42,285 --> 01:08:45,620
The UI kinda turns a little bit. It looks through my
Xcode 的界面发生了些变化，他会

1374
01:08:45,688 --> 01:08:49,223
entire project and finds that cardButons everywhere
从我整个项目里查找 cardButons 出现的每一个地方

1375
01:08:49,291 --> 01:08:53,494
including in my storyboard. See that? So now if I change
包括 storyboard 里的，看到了吗？所以现在如果我更改

1376
01:08:53,563 --> 01:08:57,665
this to cardButtons here, it changes it everywhere and
为 cardButtons 的话，它每个地方都会被修改了

1377
01:08:57,734 --> 01:09:01,669
now, this is not broken. And if I right-click on this,
现在这个就没有断开了，然后我右键这个

1378
01:09:01,738 --> 01:09:05,272
it cardButtons. So command click rename. That's how you
关联的是 cardButtons。总结一下，command，点击，Rename

1379
01:09:05,341 --> 01:09:07,308
want to rename things that touch both your UI and
这就是你想要同时重命名界面和代码的方法

1380
01:09:07,377 --> 01:09:11,812
your code. Right, so I've got this card buttons here. Now,
好，我们有了 cardButtons

1381
01:09:11,881 --> 01:09:15,716
I need to somehow in touch card, I need to
我需要在 touchCard 里

1382
01:09:15,785 --> 01:09:19,920
look into my card buttons array and find that button.
去 cardButtons 里找到那个按钮

1383
01:09:19,989 --> 01:09:22,990
Okay? By the way, before we do that, let me put the rest of
等等，在那之前，让我先把剩下的

1384
01:09:23,058 --> 01:09:25,926
these cards in there. I'm going to show you another way
这些卡片关联上。我再给你看看另一种

1385
01:09:25,995 --> 01:09:28,796
to connect up your UI to your code. It's this yellow button
关联 UI 到代码的方法。是这个黄色的按钮

1386
01:09:28,864 --> 01:09:30,297
right here. You see this yellow button at the top?
就这个，看到这个在顶上的黄色按钮了吗？

1387
01:09:30,366 --> 01:09:34,134
It says view controller. This button also represents your
说的是 View Controller。这个按钮也代表了你的代码

1388
01:09:34,203 --> 01:09:37,571
code. So, if you want to control drag from here,
所以如果你想从这里按 control 拖拽

1389
01:09:37,640 --> 01:09:40,341
you can do that as well and hook up to card buttons.
你也可以这样关联上 cardButtons

1390
01:09:40,409 --> 01:09:43,277
Control drag from here. CardButtons and I'm
从这里 control 拖拽，选 cardButtons

1391
01:09:43,346 --> 01:09:45,946
intentionally not gonna hook up this card cuz I'm gonna
我故意不关联这张卡，因为我要

1392
01:09:46,015 --> 01:09:48,348
show you what happens when we don't hook up a card. So
展示给你看不管连会发生什么

1393
01:09:48,417 --> 01:09:51,652
look at cardButtons, got those three cards and not this one,
看看 cardButtons，关联了这三个，但没有这一个

1394
01:09:51,721 --> 01:09:55,556
right. All right, so how am I gonna look in cardButtons for
好，那我怎么从 cardButtons 里找到呢？

1395
01:09:55,625 --> 01:09:59,160
mine? Well of course Swift array is a fantastic class.
当然 Swift 的字典是很神奇的类（注：结构体）

1396
01:09:59,229 --> 01:10:00,861
It's got so much great functionality and
它有很多强大的功能

1397
01:10:00,930 --> 01:10:03,698
one thing it knows how to do. Is look inside and
其中一个就是在数组里找到某个元素

1398
01:10:03,766 --> 01:10:06,600
tell you what the index is of something inside of it and
然后返回它在数组里的索引

1399
01:10:06,669 --> 01:10:09,703
that method is called index of all right. So let's just call
这个方法的名字就是 index(of:)。让我们来调用

1400
01:10:09,772 --> 01:10:13,674
that method, I'm gonna create a var called card number
这个方法。我要创建一个叫做 cardNumber 的变量

1401
01:10:13,743 --> 01:10:16,977
which I want to be the number the card 0,1,2,3,4 wherever it
也就是是第几张卡，比如 0，1，2，3，4

1402
01:10:17,046 --> 01:10:21,482
is in the array. I'm gonna set that equal to cardButtons dot,
就是在数组里的位置。我把它赋值为 cardButtons.

1403
01:10:21,551 --> 01:10:25,419
right sending a message card button index. Now interesting,
发送消息给 cardButtons.index 有趣的是

1404
01:10:25,488 --> 01:10:29,023
look how many methods are called index in array,
看看有多少数组的方法叫做 index

1405
01:10:29,092 --> 01:10:33,360
multiple methods. In Swift, that's perfectly legal. Swift,
Swift 里多个方法是可以重名的

1406
01:10:33,429 --> 01:10:36,531
you can have 100 methods all with the same index, but they
你可以有 100 个方法都叫 index，但是

1407
01:10:36,599 --> 01:10:39,200
all have to have different arguments. You see how all of
每一个都要有不同的参数。看到所有这些

1408
01:10:39,268 --> 01:10:41,235
these index methods have different arguments?
index 方法都有不同的参数吗？

1409
01:10:41,303 --> 01:10:43,303
All right, and they get the index after something,
比如某个索引之后的索引

1410
01:10:43,372 --> 01:10:44,671
index before something whatever.
某个索引之前的索引这些

1411
01:10:44,740 --> 01:10:47,809
I want this one down here index of something which is
我想要的这个 index(of:) 在下面

1412
01:10:47,877 --> 01:10:51,412
returns a int, okay, that's gonna be a problem that int,
返回的是 Int?。这个类型会成为一个问题

1413
01:10:51,481 --> 01:10:53,581
we're gonna see in a second here but
我们等会儿就会遇到

1414
01:10:53,650 --> 01:10:56,884
if I double click that, I've got the index here. So,
但我先双击使用它。我们有了 index 这个方法

1415
01:10:56,953 --> 01:10:59,653
I wanna find the index of the sender cuz I'm in touch card
我想要找到 sender 在数组里的索引，因为我按下的卡片

1416
01:10:59,722 --> 01:11:02,790
right here, so this sender and I'm just gonna print this out.
就在那里，然后我就直接把这个打印出来

1417
01:11:02,859 --> 01:11:05,560
So I'm gonna say card number equals and
print("cardNumber = \(cardNumber)")

1418
01:11:05,628 --> 01:11:08,196
we'll do our magic thing here, and
用了神奇的字符串插值

1419
01:11:08,264 --> 01:11:11,231
we will just print out the card number, okay.
然后打印出了是第几张卡

1420
01:11:11,300 --> 01:11:13,734
So before we go look in up in an array and find the emoji,
在我们到数组里找出表情符号之前

1421
01:11:13,803 --> 01:11:16,137
let's just make sure that we're finding the right card
我们先确认我们找到的是正确的卡片

1422
01:11:16,206 --> 01:11:20,041
right here. Now, right away I get two warnings here.
注意我马上就有了两个警告

1423
01:11:20,109 --> 01:11:22,543
Hm, let's go look at these warnings in depth.
让我们仔细研究下这两个警告

1424
01:11:22,612 --> 01:11:24,846
Let's make our whole screen show these warnings.
让我们全屏显示这两个警告

1425
01:11:24,914 --> 01:11:28,549
The first one is Variable cardNumber was never mutated.
第一个是说变量 cardNumber 从未被更改

1426
01:11:28,617 --> 01:11:30,852
Consider changing to let constant.
考虑改用 let 声明常量

1427
01:11:30,920 --> 01:11:34,489
What does that mean? Well indeed, cardNumber,
这是什么意思？确实，cardNumber

1428
01:11:34,557 --> 01:11:37,758
we give it an initial value here of looking up the card
我们通过查找给他赋了初值

1429
01:11:37,826 --> 01:11:40,461
in the card buttons array but we never change it again.
就没有从在 cardButtons 数组里的索引更改过

1430
01:11:40,530 --> 01:11:45,433
So it is not back in fact variable. It's a constant.
所以这就不是个变量，是个常量

1431
01:11:45,501 --> 01:11:49,637
Okay, and in Swift we always mark constants as constants.
注意，在 Swift 里常量总是被声明为常量

1432
01:11:49,706 --> 01:11:52,406
But we don't use const like in C and
但我们用的不是像 C 的 const

1433
01:11:52,474 --> 01:11:55,475
other languages, we use let, L-E-T.
或是其他语言那样的。我们用的是 let

1434
01:11:55,544 --> 01:11:57,978
And here's another cool thing. You see this little triangle?
这还有一个很酷的事情是，你看见这个小三角了吗？

1435
01:11:58,047 --> 01:12:02,917
If I click on it, oftentimes Swift will fix it for me.
如果我点击它，通常 Swift 会提供 Fix-it 来帮我解决问题

1436
01:12:02,985 --> 01:12:05,152
You see that where it says fix. It's saying,
看到这里写着 Fix 了吗？它说

1437
01:12:05,220 --> 01:12:08,622
you want me to replace var with let? Like yeah, sure, and
你想用 let 来代替 var 吗？好啊

1438
01:12:08,691 --> 01:12:12,427
it did, see? Now why do we use let instead of const?
然后它就这样做了。为什么我们用 let 而不是 const 呢？

1439
01:12:12,495 --> 01:12:14,929
Because we want Swift to read like English.
因为 Swift 要读起来像英文

1440
01:12:14,998 --> 01:12:18,199
let cardNumber = cardButtons.index of
让卡片序号等于卡片按钮数组里调用函数的按钮的索引

1441
01:12:18,268 --> 01:12:23,003
the sender, sounds like English to me, ish, okay? So
听起来像是通顺的英语，好吧？

1442
01:12:23,072 --> 01:12:25,606
that's better than const cardNumber =.
这比 常卡片序号 好一些

1443
01:12:25,675 --> 01:12:28,709
So you're gonna get used to using let, always use let when
所以你要习惯使用 let，总是用 let 来声明

1444
01:12:28,777 --> 01:12:32,146
something's a constant, never use var, all right?
常量，而不是用 var，好吧？

1445
01:12:32,215 --> 01:12:35,383
This other warning right here, I'm gonna ignore. And
这里还有一个警告，我先忽视掉

1446
01:12:35,452 --> 01:12:38,051
let's just see what happens here when we run.
让我们看看运行会发生什么？

1447
01:12:38,120 --> 01:12:43,057
So let's run this guy in our simulator, we're ignoring
让我们直接在模拟器运行，忽视这个

1448
01:12:43,126 --> 01:12:47,728
that, pay no attention to the yellow warning there.
不在意这个黄色的警告

1449
01:12:47,796 --> 01:12:50,431
Okay, here it is, let's click some of these buttons and
好，出来了。让我们来点这些按钮

1450
01:12:50,499 --> 01:12:53,000
see what happens. See, it's going to print.
然后看看发生什么。它应该会打印出来

1451
01:12:53,069 --> 01:12:54,668
We'll put this over on the side so you can see the code
让我们把这个放到一边，好能同时看到代码

1452
01:12:54,737 --> 01:12:58,405
at the same time. We're just gonna print out the cardNumber
我们只是打印出来 cardNumber

1453
01:12:58,474 --> 01:13:00,041
that we found by looking that index up.
通过找它的索引得到的结果

1454
01:13:00,109 --> 01:13:05,012
Ready, click. That's kind of weird, look at that,
准备，点。这有些奇怪，看看这个

1455
01:13:05,081 --> 01:13:09,016
Optional(1), Optional(2), what's that Optional about?
Optional(1)，Optional(2)，这个 Optional 是什么？

1456
01:13:09,084 --> 01:13:11,919
There seems to be seeing the card right, right, 0, 1, 2,
至少卡是找对了，0，1，2

1457
01:13:11,988 --> 01:13:15,656
but it's saying Optional, why is it saying Optional? Well,
但它一直在说 Optional，为什么呢？其实

1458
01:13:15,725 --> 01:13:19,860
this is that super important thing I was telling you about?
这就是我说的非常重要的知识点

1459
01:13:19,929 --> 01:13:24,198
Here it is. Lets option-click on index right here, and
这就是了。让我们按住 option 点击这个 index 方法

1460
01:13:24,266 --> 01:13:27,868
go look at it's documentation. And
我们去看看它的文档

1461
01:13:27,937 --> 01:13:31,372
the return value of index is not an int,
它的返回值不是普通的整数 Int

1462
01:13:31,441 --> 01:13:35,542
the return value of index is an optional,
返回值是可选（optional）的整数

1463
01:13:35,611 --> 01:13:36,944
that's what that question mark means.
这就是那个问号的意思

1464
01:13:37,012 --> 01:13:39,346
We've seen question marks all over in the documentation,
我们在文档里到处都可以看到问号

1465
01:13:39,415 --> 01:13:43,050
right? It means optional. And optional is a different
是吧？意思就是是可选的。可选类型是不一样的

1466
01:13:43,119 --> 01:13:47,388
type entirely from int. Okay, has nothing to do with int.
可选整型和整形完全不同，没有关联

1467
01:13:47,457 --> 01:13:51,859
Optional is a type that has two and only two states,
可选类型是一种类型，有且仅有两种状态

1468
01:13:51,928 --> 01:13:56,998
set and not set. It's an enumeration.
有值和缺省值，这是个枚举类型（enumeration）

1469
01:13:57,066 --> 01:13:59,634
You probably seen enumerations in other languages,
你多半在其他语言中看到过枚举类型

1470
01:13:59,702 --> 01:14:02,002
enumerations are things that have discreet set of values.
枚举类型是所有可能的值的集合

1471
01:14:02,071 --> 01:14:04,004
This one only has two values, set and not set,
可选类型只有两种值，有值和缺省值

1472
01:14:04,073 --> 01:14:07,040
that's it. But the cool things about enumerations in Swift,
就这样。但 Swift 枚举类型很酷的是

1473
01:14:07,109 --> 01:14:09,176
not a lot of other languages have this. For
并不是很多语言都有这个

1474
01:14:09,245 --> 01:14:13,246
each case of an enumeration you can have associated data,
每个枚举的情况都可以有关联值（associated value）

1475
01:14:13,315 --> 01:14:17,618
just data that goes along with that thing. Well, an optional,
就是跟随它的数据。那对于可选类型

1476
01:14:17,687 --> 01:14:20,454
when it's in the set state, has associated data,
处于有值的情况，就有关联值

1477
01:14:20,523 --> 01:14:24,324
which in this case is an int. So this index method is
在我们这里是整型 Int。所以这个 index 方法

1478
01:14:24,393 --> 01:14:28,162
returning whether or not it could find that button in
返回是否能找到那个按钮的信息

1479
01:14:28,231 --> 01:14:32,400
there by returning set or not set. And if it does find it
是通过返回有值或是缺省值。如果找到了的话

1480
01:14:32,468 --> 01:14:35,369
it also gives you the associated data of the int.
那就把索引作为关联值给你

1481
01:14:35,437 --> 01:14:38,105
That's what you're seeing down here. It's printing out,
这就是我们看到的下面这里打印出来

1482
01:14:38,174 --> 01:14:41,108
when we print cardNumber it says this is an optional.
打印 cardNumber 的时候会输出 Optional

1483
01:14:41,177 --> 01:14:43,878
It's in the set case and
它是有值的状态

1484
01:14:43,946 --> 01:14:48,816
the associated value is an int. Got that? Now what if we
关联值是整型，理解了吗？如果

1485
01:14:48,884 --> 01:14:51,218
click on the button that's not in the cardButton's array?
我们点击一个不在 cardButtons 数组里的按钮呢？

1486
01:14:51,286 --> 01:14:53,687
Let's see what that prints, that does right here. Oops,
我们看看会打印出什么，看看会做什么

1487
01:14:53,756 --> 01:14:55,923
we stopped, let's go back and run it again. I'm gonna click
我们停止运行了，那重新运行。我要按

1488
01:14:55,992 --> 01:14:57,992
on that fourth button that isn't in cardButton.
那不再数组里的第四个按钮

1489
01:14:58,060 --> 01:15:00,527
So when index looks it up it's not gonna find it.
当 index 方法在数组里找的话是找不到的

1490
01:15:00,596 --> 01:15:02,096
It's gonna return not set.
所以会返回缺省值

1491
01:15:02,164 --> 01:15:06,434
Let's see what that looks like? Click nil, N-I-L. So in
让我们看看那是什么样的。点击，出现了 nil

1492
01:15:06,502 --> 01:15:10,771
Swift the word nil means the not set case of an optional.
所以在 Swift 语言中，nil 代表可选类型缺省值

1493
01:15:10,839 --> 01:15:12,640
That's the only thing it means. In other languages,
这就是它唯一的意思。在其他语言里

1494
01:15:12,708 --> 01:15:16,043
it means zero pointer and other things. No, in Swift it
它意思是空指针一类的，但 Swift 里不是

1495
01:15:16,112 --> 01:15:20,414
always means an optional that's not set. Got that? All
它总代表可选类型缺省值，理解了吗？

1496
01:15:20,483 --> 01:15:23,184
right, so that's no good to me though, to have an optional.
这对我来说是不够好的，有一个可选类型

1497
01:15:23,252 --> 01:15:26,520
I can't look that optional up in another array of emoji,
我不能用可选类型来索引表情符号数组

1498
01:15:26,588 --> 01:15:29,756
I need the int. So how do I get that associated value in
我需要整数索引。那我如何在有值的情况下

1499
01:15:29,825 --> 01:15:32,560
the set state? Well, one way is to put
得到那个关联值呢？其中一个方法是

1500
01:15:32,628 --> 01:15:35,429
an exclamation point at the end of it. If you put
在后面加一个感叹号 !

1501
01:15:35,497 --> 01:15:37,397
an exclamation point at the end of an optional, it says,
如果你在可选类型的后面加一个感叹号，那意思是

1502
01:15:37,466 --> 01:15:41,869
assume this optional is set, and grab the associated value.
假设这个可选类型有值并且赋予关联值

1503
01:15:41,937 --> 01:15:46,874
So let's see what that looks like. You're gonna see
所以让我们看一下它是什么样子。你将会看到

1504
01:15:46,942 --> 01:15:49,243
this optional syntax is all really simple question mark,
这个可选类型语法的全部就是简单的疑问号

1505
01:15:49,311 --> 01:15:51,512
exclamation point, one characters, because it's so
感叹号，一个字符。因为它们（？和！）

1506
01:15:51,580 --> 01:15:54,047
common to do these optionals. All right, so
实在是太常见了。好的

1507
01:15:54,116 --> 01:15:57,184
here look, cardNumber = 0, 1, 2, excellent,
请看，carNumber 等于 0，1，2，棒极了

1508
01:15:57,252 --> 01:15:59,886
it's working. What do you think happens if I press this
它起作用了。你们认为如果我按下这个

1509
01:15:59,955 --> 01:16:01,655
one right here? >> Crash.
会发生什么？ >> 程序崩溃

1510
01:16:01,724 --> 01:16:03,190
exactly. Why is it gonna crash? Because you're
正是这样子。为什么它会崩溃？因为你正

1511
01:16:03,191 --> 01:16:04,657
>> Crash,

1512
01:16:04,727 --> 01:16:07,128
returning an option that's not in the set state, so we don't
返回一个可选类型缺省值，我们

1513
01:16:07,196 --> 01:16:10,064
have that associated value, so it crashes your program.
没有其关联值，所以它让你的程序崩溃了

1514
01:16:10,132 --> 01:16:12,432
And you're gonna see this crash quite a bit, okay,
并且你会看见不少这种崩溃

1515
01:16:12,501 --> 01:16:15,235
when you're developing because you'll just accidentally do
因为在你开发的过程中，你经常会做这种事情

1516
01:16:15,304 --> 01:16:17,872
this quite a bit of time. And if you look in your console,
并且如果你查看你的控制台

1517
01:16:17,941 --> 01:16:19,540
look what it says. It says an error here,
它写了什么，它会这里有一个错误:

1518
01:16:19,609 --> 01:16:23,744
fatal error unexpectedly found nil, that is to say not set
fatal error unexpectedly found nil，那是说可选类型缺省值

1519
01:16:23,813 --> 01:16:27,414
while unwrapping an optional. Get used to that error,
while unwrapping an optional。 熟悉这个错误

1520
01:16:27,483 --> 01:16:30,484
you see it all the time. Now, this might make you say, whoa,
你会一直看到它。现在它会让你说，哇

1521
01:16:30,553 --> 01:16:32,319
I'm never using exclamation points,
我绝不会再用感叹号了

1522
01:16:32,388 --> 01:16:35,355
gonna crash my program, scary. Yeah,
它会让我的程序崩溃，可怕

1523
01:16:35,424 --> 01:16:38,659
it's scary, but crashing your program can be really good,
是的，这是可怕的，但是程序崩溃其实是件好事

1524
01:16:38,727 --> 01:16:40,694
because it makes you find problems.
因为它让你找到了问题所在

1525
01:16:40,763 --> 01:16:43,898
Like in this case, that fourth button is supposed to be in
像在这个例子里，第四个按钮应该在

1526
01:16:43,966 --> 01:16:47,434
card buttons It's a bug that is not in card buttons. And
cardButtons 数组里，但是这是一个 bug，它并不在

1527
01:16:47,502 --> 01:16:50,070
if I didn't crash right there, I might not find that bug,
如果它不会立刻崩溃，我可能不会找到这个 bug

1528
01:16:50,139 --> 01:16:51,638
cuz I might not have clicked on that one,
因为我可能不会点击那张卡片

1529
01:16:51,707 --> 01:16:53,807
I might not have noticed. This way, I'm for sure gonna find,
我可能都不会注意。现在这样子，我确定我会找到这个 bug

1530
01:16:53,876 --> 01:16:56,410
it's gonna crash. And now it's gonna crash, it's gonna crash
它会崩溃。现在它会崩溃，它会崩溃

1531
01:16:56,479 --> 01:16:58,345
right where it matters, right in the debugger so
就在这个关键的地方，就在调试器里

1532
01:16:58,414 --> 01:17:01,015
I can look at it. So don't be afraid of crashes, okay?
所以我能看到它。所以不要害怕崩溃，好么？

1533
01:17:01,083 --> 01:17:04,084
Crashes can be good. But let's say you wanted to do this
崩溃可以是件好事。但是如果你想要让你的

1534
01:17:04,153 --> 01:17:05,786
code in a way that didn't crash,
代码用一种不会崩溃的方式书写

1535
01:17:05,855 --> 01:17:08,422
that kind of conditionally looked to see if it was in
可以用条件语句来判断是否它

1536
01:17:08,491 --> 01:17:09,223
the set state.
是有值的

1537
01:17:09,292 --> 01:17:12,659
And if it was, then use it, otherwise didn't do it.
如果有值，那么使用它。否则就不使用

1538
01:17:12,728 --> 01:17:17,531
To do that, instead of putting exclamation point at the end,
为了这样做，与在结尾放一个感叹号不同

1539
01:17:17,600 --> 01:17:21,969
you take that off and put if, at the beginning, okay?
你把它拿掉并且把 if 放到开头

1540
01:17:23,572 --> 01:17:28,509
And so now, if this optional right here is in the set state
这样一来，如果这个可选类型是有值的

1541
01:17:28,577 --> 01:17:33,113
then this code will execute, otherwise it won't, and won't crash. So
那么这行代码会执行，否则就不会，而且不会崩溃

1542
01:17:33,182 --> 01:17:35,382
that's if that's conditional, you can see again,
这是一个条件语句，你可以再看一次

1543
01:17:35,451 --> 01:17:40,554
optional minimum possible syntax here.
关于可选类型，最小的语法就在这里了

1544
01:17:40,623 --> 01:17:43,290
So now, we can put this print cardNumber inside here,
现在，我们可以把打印 cardNumber 语句放到里面

1545
01:17:43,359 --> 01:17:45,759
and we could even, if we wanted to, put an else.
我们甚至可以，如果我们想这样做的话，写一个 else 语句

1546
01:17:45,828 --> 01:17:49,129
Could something like chosen card was not in card buttons,
像这样，选中的卡片不在卡片按钮数组当中

1547
01:17:49,198 --> 01:17:53,133
or something like that, so we could notice that it happened.
或其他差不多的话，这样子我们能够注意到它发生了

1548
01:17:53,202 --> 01:17:54,701
And here we're conditionally doing it, so
这就是我们如何用条件语句来做这件事情

1549
01:17:54,770 --> 01:18:03,744
let's go look at this I'm gonna move,
让我们看一下结果，我要把

1550
01:18:03,813 --> 01:18:07,214
make this console wide here so you can see what's going on,
控制台弄宽一点以便你们能看到发生了什么

1551
01:18:07,282 --> 01:18:10,350
all right? So here this is still working cardNumber 0, 1,
好么? 所以它仍然可以工作 carNumber 0,1

1552
01:18:10,419 --> 01:18:13,553
2 because I'm using that if let right there. But now,
2 因为我正在使用 if let 的一个条件语句，但是现在

1553
01:18:13,622 --> 01:18:16,323
if I click on this bad button it just says chosen card was
如果我点击这个坏的按钮，它就会写着

1554
01:18:16,392 --> 01:18:17,825
not in card buttons, right?
选中的卡片不在卡片按钮数组里，是吧？

1555
01:18:17,893 --> 01:18:21,228
It says this, okay? So that's optional is how to unwrap
它是这样写的，对吧？ 所以这就是解包可选类型的方法

1556
01:18:21,297 --> 01:18:24,498
them. Super duper important. Really gonna have master this.
非常非常重要。真的需要掌握它

1557
01:18:24,567 --> 01:18:27,801
I know that's new to you. We're gonna talk about
我知道这对你们来说是新的。我们将会讨论

1558
01:18:27,870 --> 01:18:32,273
these exclamation points up here, that I mentioned before.
这些感叹号，正如我刚到提到的

1559
01:18:32,341 --> 01:18:34,341
That made it so you didn't have to initialize your thing,
它们让你不需要初始化你的变量

1560
01:18:34,410 --> 01:18:36,510
those are optionals as well. They're a little different
它们也是可选类型。他们只是有点不同的

1561
01:18:36,579 --> 01:18:38,979
kind of optional because their exclamation point instead of
可选类型，因为它们是感叹号而不是

1562
01:18:39,047 --> 01:18:42,182
question marks. Remember this index one right here?
疑问号。记住这里这个 index

1563
01:18:42,250 --> 01:18:45,352
Okay, that was a question mark one. These are exclamation
好么，这是一个疑问号。这些是感叹号

1564
01:18:45,421 --> 01:18:47,221
what one's they're slightly different optionals but
是有点不同的可选类型但是

1565
01:18:47,290 --> 01:18:49,189
they're still optional. We'll talk about that later.
他们仍然是可选类型。我们会之后继续讨论它

1566
01:18:49,258 --> 01:18:51,691
So the last thing I wanna do here is just take this
最后一件事情我想做的是讲讲

1567
01:18:51,760 --> 01:18:53,460
cardNumber that I got, and
我得到的这个 cardNumber

1568
01:18:53,529 --> 01:18:56,429
go look it up in an array of emojis. So I'm just gonna
并且在一个 emoji 数组中查询。所以我仅仅

1569
01:18:56,498 --> 01:19:01,368
make a var, I'm gonna call it emojiChoices. It's going to be
需要声明一个 var， 叫它 emojiChoices

1570
01:19:01,437 --> 01:19:04,938
an Array of String emoji strings basically.
是个 String 的数组，一个 emoji 字符串的数组

1571
01:19:05,007 --> 01:19:08,676
And you can create arrays right on a fly by doing open
然后你可以飞速创建一个数组，通过

1572
01:19:08,744 --> 01:19:12,780
square bracket and just put in the things in the arrays.
中括号，然后把东西放到数组里

1573
01:19:12,848 --> 01:19:16,349
So I'm gonna go put my emoji in here, lets go back to our
我将把我的 emoji 放到里面，让我们

1574
01:19:16,418 --> 01:19:19,687
emoji chooser, probably its in frequently used.
回到 emojiChoices 中，大概在 frequently used 里面

1575
01:19:19,756 --> 01:19:21,788
Here we go, there's the [INAUDIBLE] for
这个是

1576
01:19:21,857 --> 01:19:24,291
the pumpkin there, I'll put a pumpkin here.
南瓜，我会放到这里一个南瓜，放到这里一个南瓜

1577
01:19:24,360 --> 01:19:27,661
We'll put a ghost here, put a ghost over here,
放到这里一个幽灵，放到这里一个幽灵

1578
01:19:27,729 --> 01:19:30,831
all right? Now we've got that, so we're gonna look
好么。现在我们有了数组，我们查看

1579
01:19:30,900 --> 01:19:33,166
the cardNumber it's gonna be index 0, 1, 2, 3.
cardNumber, 它将会是索引 0，1，2，3

1580
01:19:33,235 --> 01:19:36,503
We're gonna look it up in here. While we're here let's
我们会在这里查询。让我们

1581
01:19:36,572 --> 01:19:41,008
go ahead and wire up that last wayward button that's not in
往前，关联最后一个按钮

1582
01:19:41,076 --> 01:19:45,379
the cardButtons array.
之前它还没有在 cardButtons 数组里

1583
01:19:45,448 --> 01:19:48,548
I'm gonna do that again from up here, Ctrl + drag, down to
我会再做一次，按住 control，向下拖到这里

1584
01:19:48,617 --> 01:19:51,685
here to put all four buttons in there. Go back to Automatic
把四个按钮都放到这里。回到 Automatic

1585
01:19:51,754 --> 01:19:56,990
here, and one other thing I'm gonna do is note that this,
另一件事情我要做的是，注意

1586
01:19:57,059 --> 01:20:02,396
is that necessary? No, because it's clear that
这里是必要的么？不，因为这是足够明确的

1587
01:20:02,465 --> 01:20:06,232
this is an array of strings. So if I option click on this,
它是一个字符串数组。所以如果我按住 option，点击这个

1588
01:20:06,301 --> 01:20:08,868
on emojiChoices right here, it says array of strings.
emojiChoices，它说这是一个字符串数组

1589
01:20:08,937 --> 01:20:11,839
So that again, the inferring. We would never put that colon
所以再说一次，类型推断。我们永远不要把那个冒号

1590
01:20:11,907 --> 01:20:16,276
array string there, never. Totally unnecessary. Okay, so
Array<String> 放到那里，永远。完全没有必要。好了

1591
01:20:16,345 --> 01:20:19,379
now let's say just printing the cardNumber out right here,
现在让我们把 cardNumber 在这里打印出来

1592
01:20:19,448 --> 01:20:23,217
I'm going to call my flipCard. FlipCard with emoji and
我将调用我的 flipCard 函数。实参标签是 withEmoji

1593
01:20:23,285 --> 01:20:27,921
the emoji is gonna be emojiChoices sub cardNumber,
emoji 参数是 emojiChoices[cardNumber]

1594
01:20:27,990 --> 01:20:33,727
okay, and it's on the sender. Got it, let's run it.
好的，on 的参数是 sender。搞定了，让我们运行它

1595
01:20:43,371 --> 01:20:48,508
Okay, here we go. Pumpkin, ghost.
好的，开始吧。南瓜，幽灵

1596
01:20:48,577 --> 01:20:51,811
All these considered working.
所有考虑到的都运行良好

1597
01:20:51,880 --> 01:20:54,347
Now, we might be very proud of ourselves here because we got
现在，我们可以为自己感到骄傲因为我们

1598
01:20:54,416 --> 01:20:57,117
this data-driven architecture. It's really great
实现了这个数据驱动的架构。这是非常棒的

1599
01:20:57,186 --> 01:20:59,552
we can add more buttons now. We can make 20 buttons and
我们现在可以添加更多的按钮。我们可以添加20个按钮

1600
01:20:59,621 --> 01:21:01,388
all we gotta do is add more things to this array.
我们所有需要做的就是在数组里添加更多的东西

1601
01:21:01,456 --> 01:21:03,389
But this is actually not a very good architecture,
但是这实际上不是一个非常好的架构

1602
01:21:03,458 --> 01:21:07,260
because this is very fragile, okay. The number of emoji here
因为它经不起折腾。emoji 的数量

1603
01:21:07,329 --> 01:21:10,196
has to exactly match the number of buttons in the UI,
必须恰好匹配 UI 上按钮的数量

1604
01:21:10,265 --> 01:21:12,899
and you have to put them in there exactly twice.
并且你必须把他们放到那里两次

1605
01:21:12,968 --> 01:21:14,601
And they're not in random order,
他们还不是处于随机顺序

1606
01:21:14,669 --> 01:21:17,203
so the cards are always gonna be in the same place kinda
所以卡牌总是处在相同的位置

1607
01:21:17,272 --> 01:21:18,471
not a very good solution.
这不是一个好的解决方案

1608
01:21:18,540 --> 01:21:21,307
So we really need to take another step and
所以我们真的非常需要迈进另一步

1609
01:21:21,376 --> 01:21:25,345
have a real concentration engine driving our app, it's
拥有一个真正的翻牌游戏引擎来驱动我们的应用

1610
01:21:25,414 --> 01:21:29,015
doing not only all of this, but all this matching and
它将不仅做所有这些事情，还会做所有的匹配

1611
01:21:29,084 --> 01:21:32,018
all that stuff. Now to do that we're gonna use this design
和所有其他事情。为了实现这个目标，我们将要使用

1612
01:21:32,087 --> 01:21:34,587
paragraph dime I talked about the very beginning model view
我在一开始提到的 Model - View - Controller (MVC)

1613
01:21:34,656 --> 01:21:38,325
controller. So I'm gonna start Wednesday's lecture with some
所以我将会在周三的课上用一些幻灯片

1614
01:21:38,393 --> 01:21:40,693
slides explaining how model view controller works.
解释 MVC 是如何工作的

1615
01:21:40,762 --> 01:21:42,562
Then we're gonna apply model view controller here, and
之后我们将要把 MVC 应用在这上面

1616
01:21:42,631 --> 01:21:45,765
you're gonna see wow, that is a way better way, to do this.
你将会看到，哇，这是更好的实现方式

1617
01:21:45,834 --> 01:21:46,933
The much more flexible and
更灵活而且

1618
01:21:47,002 --> 01:21:51,838
extensible easy to add cards not gonna crash everything. So
扩展性更强，添加卡片更方便，任何东西都不会崩溃

1619
01:21:51,907 --> 01:21:53,907
I'll see you on Wednesday. >> For
所以我们下周三再见

1620
01:21:53,976 --> 01:22:03,383
more, please visit us at stanford.edu.
>> 更多课程详见 stanford.edu