Fix potential NRE accessing current application via Page.RealParent (#330)

* Fix potential NRE accessing current application via Page.RealParent

* Update Native Bindings Gallery to use MessagingCenter

1 files changed, 8 insertions, 31 deletions

diff --git a/Xamarin.Forms.ControlGallery.Android/Activity1.cs b/Xamarin.Forms.ControlGallery.Android/Activity1.cs
index 35f877dc..ad3945ee 100644
--- a/Xamarin.Forms.ControlGallery.Android/Activity1.cs
+++ b/Xamarin.Forms.ControlGallery.Android/Activity1.cs
@@ -205,17 +205,8 @@ namespace Xamarin.Forms.ControlGallery.Android
 
 			var app = new App ();
 
-			var mdp = app.MainPage as MasterDetailPage;
-			var detail = mdp?.Detail as NavigationPage;
-			if (detail != null) {
-				detail.Pushed += (sender, args) => {
-					var nncgPage = args.Page as NestedNativeControlGalleryPage;
-
-					if (nncgPage != null) {
-						AddNativeControls (nncgPage);
-					}
-				};
-			} 
+			// When the native control gallery loads up, it'll let us know so we can add the nested native controls
+			MessagingCenter.Subscribe<NestedNativeControlGalleryPage>(this, NestedNativeControlGalleryPage.ReadyForNativeControlsMessage, AddNativeControls);
 
 			LoadApplication (app);
 		}
@@ -327,29 +318,15 @@ namespace Xamarin.Forms.ControlGallery.Android
 			// uncomment to verify turning off title bar works. This is not intended to be dynamic really.
 			//Forms.SetTitleBarVisibility (AndroidTitleBarVisibility.Never);
 
-			var app = new App ();
+			var app = new App();
 
-			var mdp = app.MainPage as MasterDetailPage;
-			var detail = mdp?.Detail as NavigationPage;
-			if (detail != null) {
-				detail.Pushed += (sender, args) => {
-					var nncgPage = args.Page as NestedNativeControlGalleryPage;
+			// When the native control gallery loads up, it'll let us know so we can add the nested native controls
+			MessagingCenter.Subscribe<NestedNativeControlGalleryPage>(this, NestedNativeControlGalleryPage.ReadyForNativeControlsMessage, AddNativeControls);
 
-					if (nncgPage != null) {
-						AddNativeControls (nncgPage);
-					}
+			// When the native binding gallery loads up, it'll let us know so we can set up the native bindings
+			MessagingCenter.Subscribe<NativeBindingGalleryPage >(this, NativeBindingGalleryPage.ReadyForNativeBindingsMessage, AddNativeBindings);
 
-					var nncgPage1 = args.Page as NativeBindingGalleryPage;
-
-					if (nncgPage1 != null)
-					{
-						AddNativeBindings(nncgPage1);
-					}
-
-				};
-			}
-
-			LoadApplication (app);
+			LoadApplication(app);
 		}
 
 		public override void OnConfigurationChanged (global::Android.Content.Res.Configuration newConfig)