Shadows & Gradients don't work with a list view's header/footer - fix (#26637)

* Shadows & Gradients don't work with a list view's header/footer - fix

* Added snapshots

Author: kubaflo

src/Controls/src/Core/Compatibility/Handlers/ListView/Android/ListViewRenderer.cs

@@ -558,6 +558,8 @@ internal sealed class Container : ViewGroup
 		{
 			IPlatformViewHandler _child;
 
+			AView _platformView => _child?.ToPlatform() ?? _child?.PlatformView;
+
 			public Container(Context context) : base(context)
 			{
 			}
@@ -567,35 +569,35 @@ public IPlatformViewHandler Child
 				set
 				{
 					if (_child != null)
-						RemoveView(_child.PlatformView);
+						RemoveView(_platformView);
 
 					_child = value;
 
 					if (value != null)
-						AddView(value.PlatformView);
+						AddView(_platformView);
 				}
 			}
 
 			protected override void OnLayout(bool changed, int l, int t, int r, int b)
 			{
-				if (_child?.PlatformView == null)
+				if (_platformView == null)
 				{
 					return;
 				}
 
-				_child.PlatformView.Layout(0, 0, r - l, b - t);
+				_platformView.Layout(0, 0, r - l, b - t);
 			}
 
 			protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
 			{
-				if (_child?.PlatformView == null)
+				if (_platformView == null)
 				{
 					SetMeasuredDimension(0, 0);
 					return;
 				}
 
-				_child.PlatformView.Measure(widthMeasureSpec, heightMeasureSpec);
-				SetMeasuredDimension(_child.PlatformView.MeasuredWidth, _child.PlatformView.MeasuredHeight);
+				_platformView.Measure(widthMeasureSpec, heightMeasureSpec);
+				SetMeasuredDimension(_platformView.MeasuredWidth, _platformView.MeasuredHeight);
 			}
 		}
 

src/Controls/src/Core/Compatibility/Handlers/ListView/iOS/ListViewRenderer.cs

@@ -360,14 +360,14 @@ void UpdateFooterMeasure()
 
 			var size = _footerRenderer.VirtualView.Measure(Bounds.Width, double.PositiveInfinity);
 			var platformFrame = new RectangleF(0, 0, size.Width, size.Height);
-			_footerRenderer.PlatformView.Frame = platformFrame;
+			_footerRenderer.ToPlatform().Frame = platformFrame;
 			_footerRenderer.VirtualView.Arrange(platformFrame.ToRectangle());
-			Control.TableFooterView = _footerRenderer.PlatformView;
+			Control.TableFooterView = _footerRenderer.ToPlatform();
 
 			BeginInvokeOnMainThread(() =>
 			{
 				if (_footerRenderer != null)
-					Control.TableFooterView = _footerRenderer.PlatformView;
+					Control.TableFooterView = _footerRenderer.ToPlatform();
 			});
 		}
 
@@ -380,9 +380,9 @@ void UpdateHeaderMeasure()
 
 			var size = _headerRenderer.VirtualView.Measure(Bounds.Width, double.PositiveInfinity);
 			var platformFrame = new RectangleF(0, 0, size.Width, size.Height);
-			_headerRenderer.PlatformView.Frame = platformFrame;
+			_headerRenderer.ToPlatform().Frame = platformFrame;
 			_headerRenderer.VirtualView.Arrange(platformFrame.ToRectangle());
-			Control.TableHeaderView = _headerRenderer.PlatformView;
+			Control.TableHeaderView = _headerRenderer.ToPlatform();
 
 			// Time for another story with Jason. Gather round children because the following Math.Ceiling will look like it's completely useless.
 			// You will remove it and test and find everything is fiiiiiine, but it is not fine, no it is far from fine. See iOS, or at least iOS 8
@@ -395,7 +395,7 @@ void UpdateHeaderMeasure()
 			BeginInvokeOnMainThread(() =>
 			{
 				if (_headerRenderer != null)
-					Control.TableHeaderView = _headerRenderer.PlatformView;
+					Control.TableHeaderView = _headerRenderer.ToPlatform();
 			});
 		}
 

src/Controls/tests/TestCases.Android.Tests/snapshots/android/GradientAndShadowShouldWork.png

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage
+        xmlns:controls="clr-namespace:Maui.Controls.Sample.Issues"
+        xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+        x:Class="Maui.Controls.Sample.Issues.Issue26636">
+        <StackLayout>
+                <ListView
+                        VerticalOptions="Center"
+                        HeightRequest="300">
+                        <ListView.Header>
+                                <Label
+                                        FontSize="16"
+                                        AutomationId="HeaderLabel"
+                                        HorizontalTextAlignment="Center"
+                                        Text="(Header) This is a border with shadows">
+                                        <Label.Background>
+                                                <LinearGradientBrush
+                                                        StartPoint="0, 0"
+                                                        EndPoint="1, 1">
+                                                        <LinearGradientBrush.GradientStops>
+                                                                <GradientStop Color="#8A2387"
+                                                                              Offset="0.1"/>
+                                                                <GradientStop Color="#E94057"
+                                                                              Offset="0.6"/>
+                                                                <GradientStop Color="#F27121"
+                                                                              Offset="1.0"/>
+                                                        </LinearGradientBrush.GradientStops>
+                                                </LinearGradientBrush>
+                                        </Label.Background>
+                                </Label>
+                        </ListView.Header>
+                        <ListView.Footer>
+                                <Label
+                                        FontSize="16"
+                                        HorizontalTextAlignment="Center"
+                                        Text="(Footer) This is a label with shadows">
+                                        <Label.Shadow>
+                                                <Shadow
+                                                        Brush="Green"
+                                                        Radius="4"
+                                                        Offset="0,4"/>
+                                        </Label.Shadow>
+                                </Label>
+                        </ListView.Footer>
+                </ListView>
+        </StackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue26636.xaml

@@ -0,0 +1,12 @@
+namespace Maui.Controls.Sample.Issues
+{
+
+	[Issue(IssueTracker.Github, 26636, "Shadows & Gradients don't work with a list view's header/footer", PlatformAffected.Android | PlatformAffected.iOS)]
+	public partial class Issue26636 : ContentPage
+	{
+		public Issue26636()
+		{
+			InitializeComponent();
+		}
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue26636.xaml.cs

@@ -0,0 +1,25 @@
+#if ANDROID || IOS
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue26636 : _IssuesUITest
+	{
+		public Issue26636(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "Shadows & Gradients don't work with a list view's header/footer";
+
+		[Test]
+		[Category(UITestCategories.ListView)]
+		public void GradientAndShadowShouldWork()
+		{
+			App.WaitForElement("HeaderLabel");
+			VerifyScreenshot();
+		}
+	}
+}
+#endif