[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

2 files changed, 226 insertions, 0 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla40333.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla40333.cs
new file mode 100644
index 00000000..3d2df2a7
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla40333.cs
@@ -0,0 +1,225 @@
+using System;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+#if UITEST
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 40333, "[Android] IllegalStateException: Recursive entry to executePendingTransactions", PlatformAffected.Android)]
+	public class Bugzilla40333 : TestNavigationPage
+	{
+		const string StartNavPageTestId = "StartNavPageTest";
+		const string OpenMasterId = "OpenMaster";
+		const string StartTabPageTestId = "StartTabPageTest";
+		const string StillHereId = "3 Still Here";
+		const string ClickThisId = "2 Click This";
+
+		protected override void Init()
+		{
+			var navButton = new Button { Text = "Test With NavigationPage", AutomationId = StartNavPageTestId };
+			navButton.Clicked += (sender, args) => { PushAsync(new _40333MDP(false)); };
+
+			var tabButton = new Button { Text = "Test With TabbedPage", AutomationId = StartTabPageTestId };
+			tabButton.Clicked += (sender, args) => { PushAsync(new _40333MDP(true)); };
+
+			var content = new ContentPage {
+				Content = new StackLayout {
+					Children = { navButton, tabButton }
+				}
+			};
+
+			PushAsync(content);
+		}
+
+		[Preserve(AllMembers = true)]
+		public class _40333MDP : TestMasterDetailPage
+		{
+			readonly bool _showTabVersion;
+
+			public _40333MDP(bool showTabVersion)
+			{
+				_showTabVersion = showTabVersion;
+			}
+
+			protected override void Init()
+			{
+				Master = new NavigationPage(new _40333NavPusher("Root")) { Title = "MasterNav" };
+
+				if (_showTabVersion)
+				{
+					Detail = new TabbedPage() { Title = "DetailNav", Children = { new _40333DetailPage("T1") } };
+				}
+				else
+				{
+					Detail = new NavigationPage(new _40333DetailPage("Detail") { Title = "DetailPage" }) { Title = "DetailNav" };
+				}
+			}
+
+			[Preserve(AllMembers = true)]
+			public class _40333DetailPage : ContentPage
+			{
+				public _40333DetailPage(string title)
+				{
+					Title = title;
+
+					var openMaster = new Button {
+						Text = "Open Master",
+						AutomationId = OpenMasterId
+					};
+
+					openMaster.Clicked += (sender, args) => ((MasterDetailPage)Parent.Parent).IsPresented = true;
+
+					Content = new StackLayout() {
+						Children = { new Label { Text = "Detail Text" }, openMaster }
+					};
+				}
+			}
+
+			[Preserve(AllMembers = true)]
+			public class _40333NavPusher : ContentPage
+			{
+				readonly ListView _listView = new ListView();
+
+				public _40333NavPusher(string title)
+				{
+					Title = title;
+
+					_listView.ItemTemplate = new DataTemplate(() =>
+					{
+						var lbl = new Label();
+						lbl.SetBinding(Label.TextProperty, ".");
+						lbl.AutomationId = lbl.Text;
+
+						var result = new ViewCell
+						{
+							View = new StackLayout
+							{
+								Orientation = StackOrientation.Horizontal,
+								Children =
+								{
+									lbl
+								}
+							}
+						};
+
+						return result;
+					});
+
+					_listView.ItemsSource = new[] { "1", ClickThisId, StillHereId };
+					_listView.ItemTapped += OnItemTapped;
+
+					Content = new StackLayout {
+						Children = { _listView }
+					};
+				}
+
+				async void OnItemTapped(object sender, EventArgs e)
+				{
+					var masterNav = ((MasterDetailPage)this.Parent.Parent).Master.Navigation;
+
+					var newTitle = $"{Title}.{_listView.SelectedItem}";
+					await masterNav.PushAsync(new _40333NavPusher(newTitle));
+				}
+
+				protected override async void OnAppearing()
+				{
+					base.OnAppearing();
+
+					var newPage = new _40333DetailPage(Title);
+
+					var detailNav = ((MasterDetailPage)this.Parent.Parent).Detail.Navigation;
+					var currentRoot = detailNav.NavigationStack[0];
+					detailNav.InsertPageBefore(newPage, currentRoot);
+					await detailNav.PopToRootAsync();
+				}
+			}
+
+			[Preserve(AllMembers = true)]
+			public class _40333TabPusher : ContentPage
+			{
+				readonly ListView _listView = new ListView();
+
+				public _40333TabPusher(string title)
+				{
+					Title = title;
+
+					_listView.ItemTemplate = new DataTemplate(() => {
+						var lbl = new Label();
+						lbl.SetBinding(Label.TextProperty, ".");
+						lbl.AutomationId = lbl.Text;
+
+						var result = new ViewCell {
+							View = new StackLayout {
+								Orientation = StackOrientation.Horizontal,
+								Children =
+								{
+									lbl
+								}
+							}
+						};
+
+						return result;
+					});
+
+					_listView.ItemsSource = new[] { "1", ClickThisId, StillHereId };
+					_listView.ItemTapped += OnItemTapped;
+
+					Content = new StackLayout {
+						Children = { _listView }
+					};
+				}
+
+				async void OnItemTapped(object sender, EventArgs e)
+				{
+					var masterNav = ((MasterDetailPage)this.Parent.Parent).Master.Navigation;
+
+					var newTitle = $"{Title}.{_listView.SelectedItem}";
+					await masterNav.PushAsync(new _40333TabPusher(newTitle));
+				}
+
+				protected override void OnAppearing()
+				{
+					base.OnAppearing();
+
+					var newPage = new _40333DetailPage(Title);
+
+					var detailTab = (TabbedPage)((MasterDetailPage)this.Parent.Parent).Detail;
+
+					detailTab.Children.Add(newPage);
+					detailTab.CurrentPage = newPage;
+				}
+			}
+		}
+
+#if UITEST
+		[Test]
+		public void ClickingOnMenuItemInMasterDoesNotCrash_NavPageVersion()
+		{
+			RunningApp.Tap(q => q.Marked(StartNavPageTestId));
+			RunningApp.WaitForElement(q => q.Marked(OpenMasterId));
+
+			RunningApp.Tap(q => q.Marked(OpenMasterId));
+			RunningApp.WaitForElement(q => q.Marked(ClickThisId));
+
+			RunningApp.Tap(q => q.Marked(ClickThisId));
+			RunningApp.WaitForElement(q => q.Marked(StillHereId)); // If the bug isn't fixed, the app will have crashed by now
+		}
+
+		[Test]
+		public void ClickingOnMenuItemInMasterDoesNotCrash_TabPageVersion()
+		{
+			RunningApp.Tap(q => q.Marked(StartTabPageTestId));
+			RunningApp.WaitForElement(q => q.Marked(OpenMasterId));
+
+			RunningApp.Tap(q => q.Marked(OpenMasterId));
+			RunningApp.WaitForElement(q => q.Marked(ClickThisId));
+
+			RunningApp.Tap(q => q.Marked(ClickThisId));
+			RunningApp.WaitForElement(q => q.Marked(StillHereId)); // If the bug isn't fixed, the app will have crashed by now
+		}
+#endif
+	}
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index 7a1892b0..306c42cd 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -101,6 +101,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40173.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla39821.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40185.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla40333.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)CarouselAsync.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34561.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34727.cs" />