[Android] Fix crash disconnecting the IndicatorView (#11346)

* Fix crash disconnecting the IndicatorView on Android

* Added IndicatorViewStub

Co-authored-by: Rui Marinho <me@ruimarinho.net>

src/Core/src/Handlers/IndicatorView/IndicatorViewHandler.Android.cs

@@ -12,13 +12,17 @@ protected override MauiPageControl CreatePlatformView()
 		private protected override void OnConnectHandler(AView platformView)
 		{
 			base.OnConnectHandler(platformView);
-			PlatformView.SetIndicatorView(VirtualView);
+
+			if(platformView is MauiPageControl pageControl)
+				pageControl.SetIndicatorView(VirtualView);
 		}
 
 		private protected override void OnDisconnectHandler(AView platformView)
 		{
 			base.OnDisconnectHandler(platformView);
-			PlatformView.SetIndicatorView(null);
+
+			if (platformView is MauiPageControl pageControl)
+				pageControl.SetIndicatorView(null);
 		}
 
 		public static void MapCount(IIndicatorViewHandler handler, IIndicatorView indicator)

src/Core/src/Handlers/IndicatorView/IndicatorViewHandler.Windows.cs

@@ -12,7 +12,9 @@ public partial class IndicatorViewHandler : ViewHandler<IIndicatorView, MauiPage
 		protected override void ConnectHandler(MauiPageControl platformView)
 		{
 			base.ConnectHandler(platformView);
-			PlatformView?.SetIndicatorView(VirtualView);
+
+			platformView?.SetIndicatorView(VirtualView);
+
 			UpdateIndicator();
 		}
 

src/Core/src/Handlers/IndicatorView/IndicatorViewHandler.iOS.cs

@@ -10,14 +10,17 @@ public partial class IndicatorViewHandler : ViewHandler<IIndicatorView, MauiPage
 		protected override void ConnectHandler(MauiPageControl platformView)
 		{
 			base.ConnectHandler(platformView);
-			PlatformView?.SetIndicatorView(VirtualView);
+
+			platformView?.SetIndicatorView(VirtualView);
+
 			UpdateIndicator();
 		}
 
 		protected override void DisconnectHandler(MauiPageControl platformView)
 		{
 			base.DisconnectHandler(platformView);
-			PlatformView?.SetIndicatorView(null);
+
+			platformView?.SetIndicatorView(null);
 		}
 
 		public static void MapCount(IIndicatorViewHandler handler, IIndicatorView indicator)

src/Core/tests/DeviceTests/Handlers/IndicatorView/IndicatorViewHandlerTests.Android.cs

@@ -0,0 +1,7 @@
+namespace Microsoft.Maui.DeviceTests
+{
+	public partial class IndicatorViewHandlerTests
+	{
+
+	}
+}

src/Core/tests/DeviceTests/Handlers/IndicatorView/IndicatorViewHandlerTests.Windows.cs

@@ -0,0 +1,7 @@
+namespace Microsoft.Maui.DeviceTests
+{
+	public partial class IndicatorViewHandlerTests
+	{
+
+	}
+}

src/Core/tests/DeviceTests/Handlers/IndicatorView/IndicatorViewHandlerTests.cs

@@ -0,0 +1,10 @@
+using Microsoft.Maui.DeviceTests.Stubs;
+
+namespace Microsoft.Maui.DeviceTests
+{
+	[Category(TestCategory.IndicatorView)]
+	public partial class IndicatorViewHandlerTests : CoreHandlerTestBase<IndicatorViewHandler, IndicatorViewStub>
+	{
+
+	}
+}

src/Core/tests/DeviceTests/Handlers/IndicatorView/IndicatorViewHandlerTests.iOS.cs

@@ -0,0 +1,7 @@
+namespace Microsoft.Maui.DeviceTests
+{
+	public partial class IndicatorViewHandlerTests
+	{
+
+	}
+}

src/Core/tests/DeviceTests/Stubs/IndicatorViewStub.cs

@@ -0,0 +1,21 @@
+namespace Microsoft.Maui.DeviceTests.Stubs
+{
+	public class IndicatorViewStub : StubBase, IIndicatorView
+	{
+		public int Count { get; set; }
+
+		public int Position { get; set; }
+
+		public double IndicatorSize { get; set; } = 6.0d;
+
+		public int MaximumVisible { get; set; } = int.MaxValue;
+
+		public bool HideSingle { get; set; }
+
+		public Paint IndicatorColor { get; set; } = new SolidPaint(Colors.Black);
+
+		public Paint SelectedIndicatorColor { get; set; } = new SolidPaint(Colors.Grey);
+
+		public IShape IndicatorsShape { get; set; }
+	}
+}

src/Core/tests/DeviceTests/TestCategory.cs

@@ -22,6 +22,7 @@ public static class TestCategory
 		public const string Image = "Image";
 		public const string ImageButton = "ImageButton";
 		public const string ImageSource = "ImageSource";
+		public const string IndicatorView = "IndicatorView";
 		public const string Label = "Label";
 		public const string Layout = "Layout";
 		public const string NavigationView = "NavigationView";