[Android] Fix: Modal Animation Repeats When Returning from Background 3 (#29702)

* fix

* dispose listner once not needed

* Revert "dispose listner once not needed"

* call invalidate

* add device test to check for leaks

* null check and remove strong references in callback

* Throw if rootview is null before adding animation

* fix spelling mistake

Author: bhavanesh2001

src/Controls/src/Core/Platform/ModalNavigationManager/ModalNavigationManager.Android.cs

@@ -305,11 +305,34 @@ public override AView OnCreateView(LayoutInflater inflater, ViewGroup? container
 
 				_navigationRootManager = modalContext.GetNavigationRootManager();
 				_navigationRootManager.Connect(_modal, modalContext);
-
+				
 				UpdateBackgroundColor();
 
-				return _navigationRootManager?.RootView ??
+				var rootView = _navigationRootManager?.RootView ??
 					throw new InvalidOperationException("Root view not initialized");
+
+				if (IsAnimated)
+				{
+					_ = new GenericGlobalLayoutListener((listener,view) =>
+					{
+						listener.Invalidate();
+						if(view is not null)
+						{
+							var animation = AnimationUtils.LoadAnimation(view.Context, Resource.Animation.nav_modal_default_enter_anim)!;
+							view.StartAnimation(animation);
+							animation.AnimationEnd += OnAnimationEnded;
+						}
+					},_navigationRootManager.RootView);
+				}
+				return rootView;
+			}
+			void OnAnimationEnded(object? sender, AAnimation.AnimationEndEventArgs e)
+			{
+				if (sender is not AAnimation animation)
+					return;
+
+				animation.AnimationEnd -= OnAnimationEnded;
+			    FireAnimationEnded();
 			}
 
 			public override void OnCreate(Bundle? savedInstanceState)
@@ -329,26 +352,7 @@ public override void OnStart()
 
 				int width = ViewGroup.LayoutParams.MatchParent;
 				int height = ViewGroup.LayoutParams.MatchParent;
-				dialog.Window.SetLayout(width, height);
-
-				if (IsAnimated)
-				{
-					var animation = AnimationUtils.LoadAnimation(_mauiWindowContext.Context, Resource.Animation.nav_modal_default_enter_anim)!;
-					View.StartAnimation(animation);
-
-					animation.AnimationEnd += OnAnimationEnded;
-				}
-
-				void OnAnimationEnded(object? sender, AAnimation.AnimationEndEventArgs e)
-				{
-					if (sender is not AAnimation animation)
-					{
-						return;
-					}
-
-					animation.AnimationEnd -= OnAnimationEnded;
-					FireAnimationEnded();
-				}
+				dialog.Window.SetLayout(width, height);		
 			}
 
 			public override void OnDismiss(IDialogInterface dialog)

src/Controls/tests/DeviceTests/Elements/Modal/ModalTests.cs

@@ -578,6 +578,36 @@ await CreateHandlerAndAddToWindow<IWindowHandler>(window, async handler =>
 		}
 #endif
 
+		[Fact("Dont leak with Animation")]
+		public async Task ModalPageDontLeakWithAnimation()
+		{
+			SetupBuilder();
+			var references = new List<WeakReference>();
+
+
+			var page = new ContentPage();
+			var window = new Window(page);
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(window, async handler =>
+			{
+				var modalPage = new ContentPage
+				{
+					Content = new Label { Text = "Modal Content" }
+				};
+				await page.Navigation.PushModalAsync(modalPage,true);
+				await OnLoadedAsync(modalPage);
+
+				references.Add(new WeakReference(modalPage));
+				references.Add(new WeakReference(modalPage.Handler));
+				references.Add(new WeakReference(modalPage.Handler.PlatformView));
+
+				await page.Navigation.PopModalAsync();
+				await OnUnloadedAsync(modalPage);
+			});
+
+			await AssertionExtensions.WaitForGC(references.ToArray());
+		}
+
 		class PageTypes : IEnumerable<object[]>
 		{
 			public IEnumerator<object[]> GetEnumerator()