Update ModalNavigationManager.Android.cs

Author: kubaflo

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

@@ -415,12 +415,12 @@ sealed class CallBack : OnBackPressedCallback
 				{
 					WeakReference<CustomComponentDialog> _customComponentDialog;
 
-					private ModalNavigationManager? _modalNavigationManager;
+					private WeakReference<ModalNavigationManager?> _modalNavigationManager;
 
 					public CallBack(bool enabled, CustomComponentDialog customComponentDialog, ModalNavigationManager? modalNavigationManager) : base(enabled)
 					{
 						_customComponentDialog = new(customComponentDialog);
-						_modalNavigationManager = modalNavigationManager;
+						_modalNavigationManager = new(modalNavigationManager);
 					}
 
 					public override void HandleOnBackPressed()
@@ -456,9 +456,11 @@ public override void HandleOnBackPressed()
 							}
 						}
 
-						if (!preventBackPropagation)
+						if (!preventBackPropagation && _modalNavigationManager.TryGetTarget(out var mnm))
 						{
-							_ = _modalNavigationManager?.PopModalAsync(true);
+							{
+								_ = mnm.PopModalAsync(true);
+							}
 						}
 
 						eventHandler = null;

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28811.cs

@@ -1,8 +1,10 @@
-using NUnit.Framework;
+#if ANDROID
+using NUnit.Framework;
 using UITest.Appium;
 using UITest.Core;
 
 namespace Microsoft.Maui.TestCases.Tests.Issues;
+
 public class Issue28811 : _IssuesUITest
 {
 	public Issue28811(TestDevice testDevice) : base(testDevice)
@@ -21,4 +23,5 @@ public void OverridingBackButtonShouldNotCauseStackOverflow()
 		App.Back();
 		App.WaitForElement("NavigateToDetailPage");
 	}
-}
+}
+#endif