Update View Enabled property when IsEnabled changes (#968)

* Actually update Enabled on Android renderers

* Fix test number

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla36703.cs

@@ -0,0 +1,65 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 36703, "TapGestureRecognizer inside initially disable Image will never fire Tapped event", PlatformAffected.All)]
+	public class Bugzilla36703 : TestContentPage
+	{
+		const string TestImage = "testimage";
+		const string Success = "Success";
+		const string Toggle = "toggle";
+		const string Testing = "Testing...";
+
+		protected override void Init()
+		{
+			var image = new Image { Source = "coffee.png", IsEnabled = false, AutomationId = TestImage };
+			var button = new Button { Text = $"Toggle IsEnabled (now {image.IsEnabled})", AutomationId = Toggle };
+			var resultLabel = new Label { Text = "Testing..."};
+			var instructions = new Label { Text = $"Tap the image. The '{Testing}' label should remain unchanged. Tap the 'Toggle IsEnabled' button. Now tap the image again. The {Testing} Label should change its text to {Success}." };
+			
+			button.Clicked += (sender, args) =>
+			{
+				image.IsEnabled = !image.IsEnabled;
+				button.Text = $"Toggle IsEnabled (now {image.IsEnabled})";
+			};
+
+			Content = new StackLayout
+			{
+				Padding = new Thickness(0, 20, 0, 0),
+				Children =
+				{
+					instructions, resultLabel,
+					image, button
+				}
+			};
+
+			var tapGestureRecognizer = new TapGestureRecognizer();
+			tapGestureRecognizer.Tapped += delegate
+			{
+				resultLabel.Text = Success;
+			};
+
+			image.GestureRecognizers.Add(tapGestureRecognizer);
+		}
+
+#if UITEST
+		[Test]
+		public void _36703Test()
+		{
+			RunningApp.WaitForElement(TestImage);
+			RunningApp.Tap(TestImage);
+			RunningApp.WaitForElement(Testing);
+			RunningApp.Tap(Toggle);
+			RunningApp.Tap(TestImage);
+			RunningApp.WaitForElement(Success);
+		}
+#endif
+	}
+}

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

@@ -82,6 +82,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla36649.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla36559.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla36171.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla36703.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla36846.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla36955.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla37462.cs" />

Xamarin.Forms.Platform.Android/VisualElementTracker.cs

@@ -160,6 +160,8 @@ namespace Xamarin.Forms.Platform.Android
 				UpdateTranslationX();
 			else if (e.PropertyName == VisualElement.TranslationYProperty.PropertyName)
 				UpdateTranslationY();
+			else if (e.PropertyName == VisualElement.IsEnabledProperty.PropertyName)
+				UpdateIsEnabled();
 		}
 
 		void HandleRedrawNeeded(object sender, EventArg<VisualElement> e)
@@ -382,6 +384,11 @@ namespace Xamarin.Forms.Platform.Android
 			aview.TranslationY = _context.ToPixels(view.TranslationY);
 		}
 
+		void UpdateIsEnabled()
+		{
+			_renderer.View.Enabled = _renderer.Element.IsEnabled;
+		}
+
 		class AttachTracker : Object, AView.IOnAttachStateChangeListener
 		{
 			public static readonly AttachTracker Instance = new AttachTracker();