[Android] Isolate fragment management for children of MasterDetailPage (#136)

* Isolate fragment management for children of MasterDetailPage in AppCompat
If a MasterDetailPage hosts NavigationPages or TabbedPages in either the
Master or Detail sections, wrap those pages in their own Fragment (and
ChildFragmentManager) to isolate their Fragment management operations and
avoid recursive entry into the executePendingTransactions method
Also fix a disposal bug in the custom MDP renderer in Control Gallery

* Remove MDP Split setting that breaks test on iPad

1 files changed, 21 insertions, 14 deletions

diff --git a/Xamarin.Forms.Platform.Android/Renderers/MasterDetailContainer.cs b/Xamarin.Forms.Platform.Android/Renderers/MasterDetailContainer.cs
index c23eb7c7..9184e269 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/MasterDetailContainer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/MasterDetailContainer.cs
@@ -1,8 +1,10 @@
 using System;
+using Android.App;
 using Android.Content;
 using Android.Content.Res;
 using Android.Runtime;
 using Android.Views;
+using Android.Widget;
 
 namespace Xamarin.Forms.Platform.Android
 {
@@ -40,19 +42,24 @@ namespace Xamarin.Forms.Platform.Android
 
 				if (_childView == null)
 					return;
+				
+				AddChildView(_childView);
+			}
+		}
 
-				IVisualElementRenderer renderer = Platform.GetRenderer(_childView);
-				if (renderer == null)
-					Platform.SetRenderer(_childView, renderer = Platform.CreateRenderer(_childView));
-
-				if (renderer.ViewGroup.Parent != this)
-				{
-					if (renderer.ViewGroup.Parent != null)
-						renderer.ViewGroup.RemoveFromParent();
-					SetDefaultBackgroundColor(renderer);
-					AddView(renderer.ViewGroup);
-					renderer.UpdateLayout();
-				}
+		protected virtual void AddChildView(VisualElement childView)
+		{
+			IVisualElementRenderer renderer = Platform.GetRenderer(childView);
+			if (renderer == null)
+				Platform.SetRenderer(childView, renderer = Platform.CreateRenderer(childView));
+
+			if (renderer.ViewGroup.Parent != this)
+			{
+				if (renderer.ViewGroup.Parent != null)
+					renderer.ViewGroup.RemoveFromParent();
+				SetDefaultBackgroundColor(renderer);
+				AddView(renderer.ViewGroup);
+				renderer.UpdateLayout();
 			}
 		}
 
@@ -97,7 +104,7 @@ namespace Xamarin.Forms.Platform.Android
 				MasterDetailPageController.DetailBounds = bounds;
 
 			IVisualElementRenderer renderer = Platform.GetRenderer(_childView);
-			renderer.UpdateLayout();
+			renderer?.UpdateLayout();
 		}
 
 		void DisposeChildRenderers()
@@ -132,7 +139,7 @@ namespace Xamarin.Forms.Platform.Android
 			return new Rectangle(xPos, padding, width, height - padding);
 		}
 
-		void SetDefaultBackgroundColor(IVisualElementRenderer renderer)
+		protected void SetDefaultBackgroundColor(IVisualElementRenderer renderer)
 		{
 			if (ChildView.BackgroundColor == Color.Default)
 			{