[Android] Fix: TapGestureRecognizer not firing on horizontal ScrollView

src/Controls/tests/TestCases.HostApp/Issues/Issue28064.cs

@@ -0,0 +1,78 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 28064, "TapGestureRecognizer on ScrollView background does not fire on Android", PlatformAffected.Android)]
+public class Issue28064 : ContentPage
+{
+	public Issue28064()
+	{
+		var statusLabel = new Label
+		{
+			Text = "Tap the brown background",
+			AutomationId = "StatusLabel"
+		};
+
+		var childStatusLabel = new Label
+		{
+			Text = "Tap a child label",
+			AutomationId = "ChildStatusLabel"
+		};
+
+		var child1 = new Label
+		{
+			BackgroundColor = Colors.LightPink,
+			WidthRequest = 100,
+			HeightRequest = 80,
+			Text = "Child1",
+			AutomationId = "Child1Label"
+		};
+		var childTapRecognizer = new TapGestureRecognizer();
+		childTapRecognizer.Tapped += (s, e) =>
+		{
+			childStatusLabel.Text = "Child Tapped";
+		};
+		child1.GestureRecognizers.Add(childTapRecognizer);
+
+		// ScrollView with Brown background — the area NOT covered by children is the tap target
+		var scrollView = new ScrollView
+		{
+			HeightRequest = 80,
+			BackgroundColor = Colors.Brown,
+			Orientation = ScrollOrientation.Horizontal,
+			AutomationId = "TheScrollView",
+			Content = new HorizontalStackLayout
+			{
+				Children =
+				{
+					child1,
+					new Label
+					{
+						BackgroundColor = Colors.LightGreen,
+						WidthRequest = 100,
+						HeightRequest = 80,
+						Text = "Child2",
+						AutomationId = "Child2Label"
+					}
+				}
+			}
+		};
+
+		var tapRecognizer = new TapGestureRecognizer();
+		tapRecognizer.Tapped += (s, e) =>
+		{
+			statusLabel.Text = "ScrollView Tapped";
+		};
+		scrollView.GestureRecognizers.Add(tapRecognizer);
+
+		Content = new VerticalStackLayout
+		{
+			Spacing = 10,
+			Padding = 10,
+			Children =
+			{
+				statusLabel,
+				childStatusLabel,
+				scrollView
+			}
+		};
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28064.cs

@@ -0,0 +1,34 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue28064 : _IssuesUITest
+{
+	public Issue28064(TestDevice device) : base(device)
+	{
+	}
+
+	public override string Issue => "TapGestureRecognizer on ScrollView background does not fire on Android";
+
+	[Test]
+	[Category(UITestCategories.ScrollView)]
+	public void ScrollViewBackgroundTapGestureShouldFire()
+	{
+		App.WaitForElement("StatusLabel");
+		App.Tap("TheScrollView");
+		var labelText = App.WaitForElement("StatusLabel").GetText();
+		Assert.That(labelText, Is.EqualTo("ScrollView Tapped"));
+	}
+
+	[Test]
+	[Category(UITestCategories.ScrollView)]
+	public void ScrollViewChildTapGestureShouldFire()
+	{
+		App.WaitForElement("ChildStatusLabel");
+		App.Tap("Child1Label");
+		var labelText = App.WaitForElement("ChildStatusLabel").GetText();
+		Assert.That(labelText, Is.EqualTo("Child Tapped"));
+	}
+}

src/Core/src/Platform/Android/MauiScrollView.cs

@@ -33,6 +33,15 @@ public class MauiScrollView : NestedScrollView, IScrollBarView, NestedScrollView
 		internal bool ShouldSkipOnTouch;
 		internal int HorizontalScrollOffset => _hScrollView?.ScrollX ?? 0;
 
+		// Stores the parent touch listener so horizontal ScrollView taps can be forwarded to it directly.
+		internal IOnTouchListener? _touchListener;
+
+		public override void SetOnTouchListener(IOnTouchListener? touchListener)
+		{
+			_touchListener = touchListener;
+			base.SetOnTouchListener(touchListener);
+		}
+
 		public MauiScrollView(Context context) : base(context)
 		{
 			_context = context;
@@ -556,6 +565,12 @@ public override bool OnTouchEvent(MotionEvent? ev)
 			// This allows ScrollView to work properly inside containers like DrawerLayout (Shell Flyout)
 			ScrollViewExtensions.HandleTouchEvent(ev, Parent);
 
+			// OnTouchEvent is only called when no child has claimed the touch event, which mirrors
+			// exactly when a vertical ScrollView's touch listener fires. We invoke the parent's
+			// stored touch listener here so TapGestureRecognizers on a horizontal/both ScrollView
+			// fire correctly.
+			_parentScrollView._touchListener?.OnTouch(_parentScrollView, ev);
+
 			// If the touch is caught by the horizontal scrollview, forward it to the parent 
 			_parentScrollView.ShouldSkipOnTouch = true;
 			_parentScrollView.OnTouchEvent(ev);

src/Core/src/PublicAPI/net-android/PublicAPI.Unshipped.txt

@@ -10,6 +10,7 @@ override Microsoft.Maui.PlatformDrawable.ThresholdType.get -> System.Type!
 *REMOVED*override Microsoft.Maui.Graphics.MauiDrawable.OnDraw(Android.Graphics.Drawables.Shapes.Shape? shape, Android.Graphics.Canvas? canvas, Android.Graphics.Paint? paint) -> void
 override Microsoft.Maui.Handlers.LabelHandler.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
 override Microsoft.Maui.Platform.MauiScrollView.OnVisibilityChanged(Android.Views.View! changedView, Android.Views.ViewStates visibility) -> void
+override Microsoft.Maui.Platform.MauiScrollView.SetOnTouchListener(Android.Views.View.IOnTouchListener? touchListener) -> void
 override Microsoft.Maui.Platform.ContentViewGroup.HasOverlappingRendering.get -> bool
 override Microsoft.Maui.Platform.LayoutViewGroup.HasOverlappingRendering.get -> bool
 override Microsoft.Maui.Platform.WrapperView.HasOverlappingRendering.get -> bool