UI tests for InputTransparent and fixes for Android/Windows (#808)

* Set up automated UI tests for InputTransparent

* Pull in Adrian's UI tests from PR 483

* Fix bugs with box/label/image gestures passing through when not transparent

* Fix disabling of layouts on Windows; fix 44096 test for iOS/Windows;

* Automate the 53445 test

8 files changed, 172 insertions, 27 deletions

diff --git a/Xamarin.Forms.Platform.Android/AppCompat/FrameRenderer.cs b/Xamarin.Forms.Platform.Android/AppCompat/FrameRenderer.cs
index 7c40ea80..d0ed345d 100644
--- a/Xamarin.Forms.Platform.Android/AppCompat/FrameRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/AppCompat/FrameRenderer.cs
@@ -31,6 +31,8 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 		VisualElementTracker _visualElementTracker;
 		NotifyCollectionChangedEventHandler _collectionChangeHandler;
 
+		bool _inputTransparent;
+
 		public FrameRenderer() : base(Forms.Context)
 		{
 			_tapGestureHandler = new TapGestureHandler(() => Element);
@@ -69,6 +71,16 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 			}
 		}
 
+		public override bool OnTouchEvent(MotionEvent e)
+		{
+			if (_inputTransparent)
+			{
+				return false;
+			}
+
+			return base.OnTouchEvent(e);
+		}
+
 		void IOnClickListener.OnClick(AView v)
 		{
 			_tapGestureHandler.OnSingleClick();
@@ -83,14 +95,16 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 					ScaleGestureDetectorCompat.SetQuickScaleEnabled(_scaleDetector.Value, true);
 				handled = _scaleDetector.Value.OnTouchEvent(e);
 			}
-
+			
 			if (_gestureDetector.IsValueCreated && _gestureDetector.Value.Handle == IntPtr.Zero)
 			{
 				// This gesture detector has already been disposed, probably because it's on a cell which is going away
 				return handled;
 			}
 
-			return _gestureDetector.Value.OnTouchEvent(e) || handled;
+			// It's very important that the gesture detection happen first here
+			// if we check handled first, we might short-circuit and never check for tap/pan
+			return _gestureDetector.Value.OnTouchEvent(e) || handled; 
 		}
 
 		VisualElement IVisualElementRenderer.Element => Element;
@@ -202,6 +216,7 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 				UpdateShadow();
 				UpdateBackgroundColor();
 				UpdateCornerRadius();
+				UpdateInputTransparent();
 				SubscribeGestureRecognizers(e.NewElement);
 			}
 		}
@@ -235,6 +250,13 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 				UpdateBackgroundColor();
 			else if (e.PropertyName == Frame.CornerRadiusProperty.PropertyName)
 				UpdateCornerRadius();
+			else if (e.PropertyName == VisualElement.InputTransparentProperty.PropertyName)
+				UpdateInputTransparent();
+		}
+
+		void UpdateInputTransparent()
+		{
+			_inputTransparent = Element.InputTransparent;
 		}
 
 		void SubscribeGestureRecognizers(VisualElement element)
diff --git a/Xamarin.Forms.Platform.Android/Platform.cs b/Xamarin.Forms.Platform.Android/Platform.cs
index ca0b9708..0fc287c9 100644
--- a/Xamarin.Forms.Platform.Android/Platform.cs
+++ b/Xamarin.Forms.Platform.Android/Platform.cs
@@ -1024,6 +1024,50 @@ namespace Xamarin.Forms.Platform.Android
 
 		internal class DefaultRenderer : VisualElementRenderer<View>
 		{
+			bool _notReallyHandled;
+			internal void NotifyFakeHandling()
+			{
+				_notReallyHandled = true;
+			}
+
+			public override bool DispatchTouchEvent(MotionEvent e)
+			{
+				#region
+				// Normally dispatchTouchEvent feeds the touch events to its children one at a time, top child first,
+				// (and only to the children in the hit-test area of the event) stopping as soon as one of them has handled
+				// the event. 
+
+				// But to be consistent across the platforms, we don't want this behavior; if an element is not input transparent
+				// we don't want an event to "pass through it" and be handled by an element "behind/under" it. We just want the processing
+				// to end after the first non-transparent child, regardless of whether the event has been handled.
+
+				// This is only an issue for a couple of controls; the interactive controls (switch, button, slider, etc) already "handle" their touches 
+				// and the events don't propagate to other child controls. But for image, label, and box that doesn't happen. We can't have those controls 
+				// lie about their events being handled because then the events won't propagate to *parent* controls (e.g., a frame with a label in it would
+				// never get a tap gesture from the label). In other words, we *want* parent propagation, but *do not want* sibling propagation. So we need to short-circuit 
+				// base.DispatchTouchEvent here, but still return "false".
+
+				// Duplicating the logic of ViewGroup.dispatchTouchEvent and modifying it slightly for our purposes is a non-starter; the method is too
+				// complex and does a lot of micro-optimization. Instead, we provide a signalling mechanism for the controls which don't already "handle" touch
+				// events to tell us that they will be lying about handling their event; they then return "true" to short-circuit base.DispatchTouchEvent.
+
+				// The container gets this message and after it gets the "handled" result from dispatchTouchEvent, 
+				// it then knows to ignore that result and return false/unhandled. This allows the event to propagate up the tree.
+				#endregion
+
+				_notReallyHandled = false;
+
+				var result = base.DispatchTouchEvent(e);
+
+				if (result && _notReallyHandled)
+				{
+					// If the child control returned true from its touch event handler but signalled that it was a fake "true", leave the event unhandled
+					// so parent controls have the opportunity
+					return false;
+				}
+
+				return result;
+			}
 		}
 
 		#region IPlatformEngine implementation
diff --git a/Xamarin.Forms.Platform.Android/Renderers/BoxRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/BoxRenderer.cs
index 380d4018..aa19d81c 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/BoxRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/BoxRenderer.cs
@@ -5,7 +5,7 @@ namespace Xamarin.Forms.Platform.Android
 {
 	public class BoxRenderer : VisualElementRenderer<BoxView>
 	{
-		bool _isInViewCell;
+		readonly MotionEventHelper _motionEventHelper = new MotionEventHelper();
 
 		public BoxRenderer()
 		{
@@ -16,26 +16,15 @@ namespace Xamarin.Forms.Platform.Android
 		{
 			if (base.OnTouchEvent(e))
 				return true;
-			return !Element.InputTransparent && !_isInViewCell;
+
+			return _motionEventHelper.HandleMotionEvent(Parent);
 		}
 
 		protected override void OnElementChanged(ElementChangedEventArgs<BoxView> e)
 		{
 			base.OnElementChanged(e);
 
-			if (e.NewElement != null)
-			{
-				var parent = e.NewElement.Parent;
-				while (parent != null)
-				{
-					if (parent is ViewCell)
-					{
-						_isInViewCell = true;
-						break;
-					}
-					parent = parent.Parent;
-				}
-			}
+			_motionEventHelper.UpdateElement(e.NewElement);
 
 			UpdateBackgroundColor();
 		}
diff --git a/Xamarin.Forms.Platform.Android/Renderers/ImageRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/ImageRenderer.cs
index e18d4b95..fee05f1b 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/ImageRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/ImageRenderer.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using System.IO;
 using System.Threading.Tasks;
 using Android.Graphics;
+using Android.Views;
 using AImageView = Android.Widget.ImageView;
 using Xamarin.Forms.Internals;
 
@@ -11,8 +12,7 @@ namespace Xamarin.Forms.Platform.Android
 	public class ImageRenderer : ViewRenderer<Image, AImageView>
 	{
 		bool _isDisposed;
-
-		IElementController ElementController => Element as IElementController;
+		readonly MotionEventHelper _motionEventHelper = new MotionEventHelper();
 
 		public ImageRenderer()
 		{
@@ -44,6 +44,8 @@ namespace Xamarin.Forms.Platform.Android
 				SetNativeControl(view);
 			}
 
+			_motionEventHelper.UpdateElement(e.NewElement);
+
 			UpdateBitmap(e.OldElement);
 			UpdateAspect();
 		}
@@ -117,5 +119,13 @@ namespace Xamarin.Forms.Platform.Android
 				((IVisualElementController)Element).NativeSizeChanged();
 			}
 		}
+
+		public override bool OnTouchEvent(MotionEvent e)
+		{
+			if (base.OnTouchEvent(e))
+				return true;
+
+			return _motionEventHelper.HandleMotionEvent(Parent);
+		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.Android/Renderers/LabelRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/LabelRenderer.cs
index c544a239..ab1a6a35 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/LabelRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/LabelRenderer.cs
@@ -4,8 +4,8 @@ using Android.Content.Res;
 using Android.Graphics;
 using Android.Text;
 using Android.Util;
+using Android.Views;
 using Android.Widget;
-using AColor = Android.Graphics.Color;
 
 namespace Xamarin.Forms.Platform.Android
 {
@@ -23,6 +23,8 @@ namespace Xamarin.Forms.Platform.Android
 		FormsTextView _view;
 		bool _wasFormatted;
 
+		readonly MotionEventHelper _motionEventHelper = new MotionEventHelper();
+
 		public LabelRenderer()
 		{
 			AutoPackage = false;
@@ -97,6 +99,8 @@ namespace Xamarin.Forms.Platform.Android
 				if (e.OldElement.HorizontalTextAlignment != e.NewElement.HorizontalTextAlignment || e.OldElement.VerticalTextAlignment != e.NewElement.VerticalTextAlignment)
 					UpdateGravity();
 			}
+
+			_motionEventHelper.UpdateElement(e.NewElement);
 		}
 
 		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
@@ -217,5 +221,13 @@ namespace Xamarin.Forms.Platform.Android
 
 			_lastSizeRequest = null;
 		}
+
+		public override bool OnTouchEvent(MotionEvent e)
+		{
+			if (base.OnTouchEvent(e))
+				return true;
+
+			return _motionEventHelper.HandleMotionEvent(Parent);
+		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.Android/Renderers/MotionEventHelper.cs b/Xamarin.Forms.Platform.Android/Renderers/MotionEventHelper.cs
new file mode 100644
index 00000000..4ed06d26
--- /dev/null
+++ b/Xamarin.Forms.Platform.Android/Renderers/MotionEventHelper.cs
@@ -0,0 +1,53 @@
+using Android.Views;
+
+namespace Xamarin.Forms.Platform.Android
+{
+	internal class MotionEventHelper
+	{
+		VisualElement _element;
+		bool _isInViewCell;
+
+		public bool HandleMotionEvent(IViewParent parent)
+		{
+			if (_isInViewCell || _element.InputTransparent)
+			{
+				return false;
+			}
+
+			var renderer = parent as Platform.DefaultRenderer;
+			if (renderer == null)
+			{
+				return false;
+			}
+
+			// Let the container know that we're "fake" handling this event
+			renderer.NotifyFakeHandling();
+
+			return true;
+		}
+
+		public void UpdateElement(VisualElement element)
+		{
+			_isInViewCell = false;
+			_element = element;
+
+			if (_element == null)
+			{
+				return;
+			}
+
+			// Determine whether this control is inside a ViewCell;
+			// we don't fake handle the events because ListView needs them for row selection
+			var parent = _element.Parent;
+			while (parent != null)
+			{
+				if (parent is ViewCell)
+				{
+					_isInViewCell = true;
+					break;
+				}
+				parent = parent.Parent;
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs b/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs
index 7f5c7f91..8f6722c3 100644
--- a/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs
@@ -92,14 +92,20 @@ namespace Xamarin.Forms.Platform.Android
 
 		public override bool OnInterceptTouchEvent(MotionEvent ev)
 		{
-			if (Element.InputTransparent && Element.IsEnabled)
-				return false;
+			if (!Element.IsEnabled || (Element.InputTransparent && Element.IsEnabled))
+				return true;
 
 			return base.OnInterceptTouchEvent(ev);
 		}
 
 		bool AView.IOnTouchListener.OnTouch(AView v, MotionEvent e)
 		{
+			if (!Element.IsEnabled)
+				return true;
+
+			if (Element.InputTransparent)
+				return false;
+
 			var handled = false;
 			if (_pinchGestureHandler.IsPinchSupported)
 			{
@@ -116,7 +122,11 @@ namespace Xamarin.Forms.Platform.Android
 				return handled;
 			}
 
-			return _gestureDetector.Value.OnTouchEvent(e) || handled;
+			// It's very important that the gesture detection happen first here
+			// if we check handled first, we might short-circuit and never check for tap/pan
+			handled = _gestureDetector.Value.OnTouchEvent(e) || handled;
+
+			return handled;
 		}
 
 		VisualElement IVisualElementRenderer.Element => Element;
@@ -191,8 +201,6 @@ namespace Xamarin.Forms.Platform.Android
 				SoundEffectsEnabled = false;
 			}
 
-			InputTransparent = Element.InputTransparent;
-
 			// must be updated AFTER SetOnClickListener is called
 			// SetOnClickListener implicitly calls Clickable = true
 			UpdateGestureRecognizers(true);
@@ -215,6 +223,7 @@ namespace Xamarin.Forms.Platform.Android
 
 			SetContentDescription();
 			SetFocusable();
+			UpdateInputTransparent();
 
 			Performance.Stop();
 		}
@@ -305,14 +314,14 @@ namespace Xamarin.Forms.Platform.Android
 		{
 			if (e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName)
 				UpdateBackgroundColor();
-			else if (e.PropertyName == VisualElement.InputTransparentProperty.PropertyName)
-				InputTransparent = Element.InputTransparent;
 			else if (e.PropertyName == Accessibility.HintProperty.PropertyName)
 				SetContentDescription();
 			else if (e.PropertyName == Accessibility.NameProperty.PropertyName)
 				SetContentDescription();
 			else if (e.PropertyName == Accessibility.IsInAccessibleTreeProperty.PropertyName)
 				SetFocusable();
+			else if (e.PropertyName == VisualElement.InputTransparentProperty.PropertyName)
+				UpdateInputTransparent();
 		}
 
 		protected override void OnLayout(bool changed, int l, int t, int r, int b)
@@ -398,6 +407,11 @@ namespace Xamarin.Forms.Platform.Android
 			return true;
 		}
 
+		void UpdateInputTransparent()
+		{
+			InputTransparent = Element.InputTransparent;
+		}
+
 		protected void SetPackager(VisualElementPackager packager)
 		{
 			_packager = packager;
diff --git a/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj b/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj
index 29562618..fd894e47 100644
--- a/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj
+++ b/Xamarin.Forms.Platform.Android/Xamarin.Forms.Platform.Android.csproj
@@ -174,6 +174,7 @@
     <Compile Include="AppCompat\ViewRenderer.cs" />
     <Compile Include="Renderers\LocalizedDigitsKeyListener.cs" />
     <Compile Include="Renderers\MasterDetailContainer.cs" />
+    <Compile Include="Renderers\MotionEventHelper.cs" />
     <Compile Include="Renderers\PageContainer.cs" />
     <Compile Include="Renderers\ScrollViewContainer.cs" />
     <Compile Include="Renderers\StreamImagesourceHandler.cs" />