More fixes.

Author: Kevin Petit

Xamarin.Forms.Platform.Android/AppCompat/FormsAppCompatActivity.cs

@@ -229,6 +229,12 @@ protected override void OnPause()
 		{
 			_layout.HideKeyboard(true);
 
+			if (Forms.IsLollipopOrNewer)
+			{
+				// Don't listen for power save mode changes while we're paused
+				UnregisterReceiver(_powerSaveModeBroadcastReceiver);
+			}
+
 			// Stop animations or other ongoing actions that could consume CPU
 			// Commit unsaved changes, build only if users expect such changes to be permanently saved when thy leave such as a draft email
 			// Release system resources, such as broadcast receivers, handles to sensors (like GPS), or any resources that may affect battery life when your activity is paused.
@@ -238,12 +244,6 @@ protected override void OnPause()
 			_previousState = _currentState;
 			_currentState = AndroidApplicationLifecycleState.OnPause;
 
-			if (Forms.IsLollipopOrNewer)
-			{
-				// Don't listen for power save mode changes while we're paused
-				UnregisterReceiver(_powerSaveModeBroadcastReceiver);
-			}
-
 			OnStateChanged();
 		}
 
@@ -320,7 +320,7 @@ void AppOnPropertyChanged(object sender, PropertyChangedEventArgs args)
 			}
 
 			if (args.PropertyName == nameof(_application.MainPage))
-				InternalSetPage(_application.MainPage);
+				SetMainPage();
 			if (args.PropertyName == PlatformConfiguration.AndroidSpecific.Application.WindowSoftInputModeAdjustProperty.PropertyName)
 				SetSoftInputMode();
 		}

Xamarin.Forms.Platform.Android/AppCompat/Platform.cs

@@ -322,7 +322,17 @@ void SetPageInternal(Page newRoot)
 
 		void Cleanup(List<AView> viewsToRemove, List<IVisualElementRenderer> renderersToDispose)
 		{
-			new Handler(Looper.MainLooper).Post(() =>
+			// If trigger by dispose, cleanup now, otherwise queue it for later
+			if (_disposed)
+			{
+				DoCleanup();
+			}
+			else
+			{
+				new Handler(Looper.MainLooper).Post(DoCleanup);
+			}
+
+			void DoCleanup()
 			{
 				for (int i = 0; i < viewsToRemove.Count; i++)
 				{
@@ -333,9 +343,10 @@ void Cleanup(List<AView> viewsToRemove, List<IVisualElementRenderer> renderersTo
 				for (int i = 0; i < renderersToDispose.Count; i++)
 				{
 					IVisualElementRenderer rootRenderer = renderersToDispose[i];
+					rootRenderer?.Element.ClearValue(Android.Platform.RendererProperty);
 					rootRenderer?.Dispose();
 				}
-			});
+			}
 		}
 
 		void AddChild(Page page, bool layout = false)