[iOS] Readonly Editor - Scrolling fix (dotnet#20505)

---------

Co-authored-by: Javier Suárez <[email protected]>
Co-authored-by: Matthew Leibowitz <[email protected]>

src/Controls/tests/TestCases.HostApp/Issues/Issue19500.xaml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue19500">
+    <Editor
+        HeightRequest="100"
+        IsReadOnly="True"
+        AutomationId="editor"
+        Text="Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla porttitor mauris non ornare ultrices. Ut semper ultrices justo eget semper.
+              Ut imperdiet dolor ut vestibulum molestie. Duis a libero ex. Etiam mi urna, lobortis sed tincidunt in, tempus eget magna. Aenean quis malesuada eros.
+              Phasellus felis eros, condimentum et tortor sed, condimentum convallis turpis. Sed in varius metus, at auctor orci. Maecenas luctus nibh nibh,
+              nec aliquam est fermentum in. Etiam consectetur lectus erat, sed placerat sapien rutrum eu. Suspendisse tincidunt fermentum tempor.
+              Maecenas egestas neque nec lacinia fringilla."/>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue19500.xaml.cs

@@ -0,0 +1,15 @@
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+
+namespace Maui.Controls.Sample.Issues
+{
+	[XamlCompilation(XamlCompilationOptions.Compile)]
+	[Issue(IssueTracker.Github, 19500, "[iOS] Editor is not be able to scroll if IsReadOnly is true", PlatformAffected.iOS)]
+	public partial class Issue19500 : ContentPage
+	{
+		public Issue19500()
+		{
+			InitializeComponent();
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue18675.cs

@@ -4,9 +4,9 @@
 
 namespace Microsoft.Maui.TestCases.Tests.Issues
 {
-	public class Issue186751 : _IssuesUITest
+	public class Issue18675 : _IssuesUITest
 	{
-		public Issue186751(TestDevice device) : base(device)
+		public Issue18675(TestDevice device) : base(device)
 		{
 		}
 

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue19500.cs

@@ -0,0 +1,28 @@
+#if IOS
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue19500 : _IssuesUITest
+	{
+		public override string Issue => "[iOS] Editor is not be able to scroll if IsReadOnly is true";
+
+		public Issue19500(TestDevice device) : base(device)
+		{
+		}
+
+		[Test]
+		[Category(UITestCategories.Editor)]
+		public void TextInEditorShouldScroll()
+		{
+			_ = App.WaitForElement("editor");
+			App.ScrollDown("editor");
+
+			// The test passes if the text inside the editor scrolls down
+			VerifyScreenshot();
+		}
+	}
+}
+#endif

src/Core/src/Platform/iOS/TextViewExtensions.cs

@@ -70,12 +70,24 @@ public static void UpdateFont(this UITextView textView, ITextStyle textStyle, IF
 
 		public static void UpdateIsReadOnly(this UITextView textView, IEditor editor)
 		{
-			textView.UserInteractionEnabled = !(editor.IsReadOnly || editor.InputTransparent);
+			textView.UpdateEditable(editor);
 		}
 
 		public static void UpdateIsEnabled(this UITextView textView, IEditor editor)
 		{
-			textView.Editable = editor.IsEnabled;
+			textView.UpdateEditable(editor);
+		}
+
+		internal static void UpdateEditable(this UITextView textView, IEditor editor)
+		{
+			var isEditable = editor.IsEnabled && !editor.IsReadOnly;
+
+			textView.Editable = isEditable;
+
+			// If the input accessory view is set, we need to hide it when the editor is read-only
+			// otherwise it will appear when the editor recieves focus.
+			if (textView.InputAccessoryView is {} view)
+				view.Hidden = !isEditable;
 		}
 
 		public static void UpdateKeyboard(this UITextView textView, IEditor editor)

src/Core/src/Platform/iOS/ViewExtensions.cs

@@ -512,7 +512,9 @@ internal static Size LayoutToMeasuredSize(this IView view, double width, double
 
 		public static void UpdateInputTransparent(this UIView platformView, IViewHandler handler, IView view)
 		{
-			if (view is ITextInput textInput)
+			// Interaction should not be disabled for an editor if it is set as read-only
+			// because this prevents users from scrolling the content inside an editor.
+			if (view is not IEditor && view is ITextInput textInput)
 			{
 				platformView.UpdateInputTransparent(textInput.IsReadOnly, view.InputTransparent);
 				return;

src/Core/tests/DeviceTests/Handlers/Editor/EditorHandlerTests.iOS.cs

@@ -256,7 +256,7 @@ double GetNativeUnscaledFontSize(EditorHandler editorHandler) =>
 			GetNativeEditor(editorHandler).Font.PointSize;
 
 		bool GetNativeIsReadOnly(EditorHandler editorHandler) =>
-			!GetNativeEditor(editorHandler).UserInteractionEnabled;
+			!GetNativeEditor(editorHandler).Editable;
 
 		bool GetNativeIsTextPredictionEnabled(EditorHandler editorHandler) =>
 			GetNativeEditor(editorHandler).AutocorrectionType == UITextAutocorrectionType.Yes;