[iOS] Fix setting text decorations and text at the same time and respect changes

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue11954.cs

@@ -0,0 +1,94 @@
+using System;
+using Xamarin.Forms.Internals;
+using Xamarin.Forms.CustomAttributes;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.Label)]
+#endif
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 11954,
+		"[Bug] iOS label can't un-set text decorations when updating text at the same time",
+		PlatformAffected.iOS)]
+	public class Issue11954 : TestContentPage
+	{
+		public Issue11954()
+		{
+			UpdateLabel();
+		}
+
+		private Label NiceLabel;
+
+		protected override void Init()
+		{
+			Title = "Issue 11954";
+
+			var layout = new StackLayout();
+
+			var instructions = new Label
+			{
+				Padding = 12,
+				BackgroundColor = Color.Black,
+				TextColor = Color.White,
+				Text = "If press the toggle button and the label enables and disables strikethrough correctly, the test has passed"
+			};
+
+			NiceLabel = new Label
+			{
+				FontSize = 16,
+				Padding = new Thickness(30,24,30,0),
+				Text = "Default text"
+			};
+
+			var button = new Button
+			{
+				Text = "Toggle"
+			};
+
+			button.Clicked += Button_Clicked;
+
+			layout.Children.Add(NiceLabel);
+			layout.Children.Add(button);
+
+			Content = layout;
+		}
+
+		private bool _isStrikethrough;
+
+		private void Button_Clicked(object sender, EventArgs e)
+		{
+			// Toggle strike-through and update label
+			_isStrikethrough = !_isStrikethrough;
+			UpdateLabel();
+		}
+
+		private void UpdateLabel()
+		{
+			NiceLabel.TextDecorations = _isStrikethrough ? TextDecorations.Strikethrough : TextDecorations.None;
+
+			// Comment out the next line and it starts working again
+			NiceLabel.Text = "Is it strikethrough? " + _isStrikethrough.ToString();
+		}
+
+#if UITEST
+		[Test]
+		[Category(UITestCategories.ManualReview)]
+		public void Issue11954Test()
+		{
+			RunningApp.Tap("Toggle");
+			RunningApp.Screenshot("Label should have strikethrough");
+			RunningApp.Tap("Toggle");
+			RunningApp.Screenshot("Label should NOT have strikethrough");
+
+			Assert.Inconclusive("For visual review only");
+		}
+#endif
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1720,7 +1720,7 @@
     </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Issue10623.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue11829.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)Issue11496.xaml.cs" >
+    <Compile Include="$(MSBuildThisFileDirectory)Issue11496.xaml.cs">
       <DependentUpon>Issue11496.xaml</DependentUpon>
     </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Issue11209.xaml.cs">
@@ -1828,6 +1828,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue14757.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue14897.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue14805.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue11954.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Bugzilla22229.xaml">
@@ -2731,7 +2732,7 @@
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue7671.xaml">
       <SubType>Designer</SubType>
-      <Generator>MSBuild:Compile</Generator>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
@@ -2946,7 +2947,7 @@
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue14765.xaml">
       <SubType>Designer</SubType>
-      <Generator>MSBuild:Compile</Generator>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13573.xaml">
       <SubType>Designer</SubType>

Xamarin.Forms.Platform.iOS/Renderers/LabelRenderer.cs

@@ -455,7 +455,7 @@ void UpdateTextPlainText()
 			{
 				var text = Element.UpdateFormsText(Element.Text, Element.TextTransform);
 #if __MOBILE__
-				Control.Text = text;
+				Control.AttributedText = new NSAttributedString(text);
 #else
 				Control.StringValue = text ?? "";
 #endif