Add transitory legacy fork for MDCChipField and MDCChipFieldDelegate.

PiperOrigin-RevId: 590253565

components/Chips/src/MDCLegacyChipField.h

@@ -0,0 +1,172 @@
+// Copyright 2017-present the Material Components for iOS authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <CoreGraphics/CoreGraphics.h>
+#import <UIKit/UIKit.h>
+
+#import "MDCChipView.h"
+#import "MaterialTextFields.h"
+
+// TODO(cl/315839473): Delete MDCLegacyChipField.h after migrating.
+
+/**
+ Note: There is a UIKit bug affecting iOS 8.0-8.2 where UITextFields do not properly call the
+ public |deleteBackward| method when the user presses backspace, which means that users can't
+ delete chips with the backspace key. Apple fixed the underlying bug in iOS 8.3, so clients
+ targeting a minimum iOS version of >= 8.3 are not affected by this bug.
+
+ As a workaround, this class can OPTIONALLY USE THE PRIVATE |keyboardInputShouldDelete| method to
+ detect when backspace is pressed and forward the event to |deleteBackward|. There is anecdotal
+ evidence that this private usage is currently acceptable by Apple, see
+ http://stackoverflow.com/a/25862878/23624.
+
+ To enable the workaround, define MDC_CHIPFIELD_PRIVATE_API_BUG_FIX to be 1 when building
+ MDCChipField. MDC itself will never define this macro, it's entirely a client decision.
+
+ If you target iOS versions < 8.3 and you decide not to define MDC_CHIPFIELD_PRIVATE_API_BUG_FIX,
+ your iOS 8.0-8.2 users will *not be able to delete chips using the backspace key*. Please
+ consider adding a delete button to each chip's accessoryView.
+
+ An alternative approach (using an empty character to detect backspace) makes MDCChipField unusable
+ by VoiceOver users on all versions of iOS.
+ */
+
+/** The minimum text field width of the text field contained within the MDCChipField. */
+extern const CGFloat MDCLegacyChipFieldDefaultMinTextFieldWidth;
+
+/** The default content edge insets for the MDCChipField. */
+extern const UIEdgeInsets MDCLegacyChipFieldDefaultContentEdgeInsets;
+
+@protocol MDCLegacyChipFieldDelegate;
+
+/** Defines when text field input is changed into a chip. */
+typedef NS_OPTIONS(NSUInteger, MDCLegacyChipFieldDelimiter) {
+  MDCLegacyChipFieldDelimiterNone = 0,
+  MDCLegacyChipFieldDelimiterReturn = 1 << 0,
+  MDCLegacyChipFieldDelimiterSpace = 1 << 1,
+  MDCLegacyChipFieldDelimiterDidEndEditing = 1 << 2,
+  MDCLegacyChipFieldDelimiterDefault = (MDCLegacyChipFieldDelimiterReturn |
+                                        MDCLegacyChipFieldDelimiterDidEndEditing),
+  MDCLegacyChipFieldDelimiterAll = 0xFFFFFFFF
+};
+
+/**
+ This class is a legacy fork of MDCChipField. It is temporary, and will be deleted after each
+ client has been individually migrated.
+ */
+@interface MDCLegacyChipField : UIView
+
+/**
+ The text field used to enter new chips.
+
+ Do not set the delegate or positioningDelegate.
+
+ If you set a custom font, make sure to also set the custom font on textField.placeholderLabel and
+ on your MDCChipView instances.
+ */
+@property(nonatomic, nonnull, readonly) MDCTextField *textField;
+
+/**
+ The fixed height of all chip views.
+
+ Default is 32dp.
+ */
+@property(nonatomic, assign) CGFloat chipHeight;
+
+/**
+ Attribute to determine whether to show the placeholder text (if it exists) when chips are
+ present.
+
+ Default is YES.
+ */
+@property(nonatomic, assign) BOOL showPlaceholderWithChips;
+
+/**
+ Enabling this property allows chips to be deleted by tapping on them.
+
+ @note This does not support the 48x48 touch targets that Google recommends. We recommend if this
+ behavior is enabled that a snackbar or dialog are used as well to allow the user to confirm if they
+ want to delete the chip.
+ */
+@property(nonatomic) BOOL showChipsDeleteButton;
+
+/**
+ The delimiter used to create chips in the text field. Uses default value
+ MDCChipFieldDelimiterDefault if no delimiter is set.
+ */
+@property(nonatomic, assign) MDCLegacyChipFieldDelimiter delimiter;
+
+/**
+ The minimum width of the text field.
+
+ Default is |kMDCChipFieldDefaultMinTextFieldWidth|.
+ */
+@property(nonatomic, assign) CGFloat minTextFieldWidth;
+
+/**
+ The chips that are visible in the input area.
+ */
+@property(nonatomic, nonnull, copy) NSArray<MDCChipView *> *chips;
+
+/**
+ Delegate to receive updates to the chip field view. Implement
+ |chipFieldHeightDidChange| to receive updates when the height of the chip field changes.
+ */
+@property(nonatomic, nullable, weak) id<MDCLegacyChipFieldDelegate> delegate;
+
+/**
+ The inset or outset margins for the rectangle surrounding all of the chip field's content.
+ Default is |kMDCChipFieldDefaultContentEdgeInsets|.
+ */
+@property(nonatomic, assign) UIEdgeInsets contentEdgeInsets;
+
+/**
+ The image used in the MDCChipViewDeleteButton.
+ Defaults to a bezier-drawn image declared in `MDCChipViewDeleteButton`.
+ */
+@property(nonatomic, nullable, strong) UIImage *deleteButtonImage;
+
+/**
+ Adds a chip to the chip field.
+
+ @param chip The chip to add to the field.
+
+ Note: Implementing |chipField:shouldAddChip| only affects whether user interface input entered into
+ the text field is changed into chips and will not affect use of this method.
+ */
+- (void)addChip:(nonnull MDCChipView *)chip;
+
+/**
+ Removes a chip from the chip field.
+
+ @param chip The chip to remove from the field.
+ */
+- (void)removeChip:(nonnull MDCChipView *)chip;
+
+/** Removes all selected chips from the chip field. */
+- (void)removeSelectedChips;
+
+/** Removes all text from the chip field text input area. */
+- (void)clearTextInput;
+
+/** Selects a chip in a chip field. */
+- (void)selectChip:(nonnull MDCChipView *)chip;
+
+/** Deselects all chips in a chip field. */
+- (void)deselectAllChips;
+
+/** Sets the VoiceOver focus on the text field. */
+- (void)focusTextFieldForAccessibility;
+
+@end