[A] Check for parent NavigationPage when setting MDP detail's TopPadding (#473)

rebased

3 files changed, 69 insertions, 2 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla44476.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla44476.cs
new file mode 100644
index 00000000..1042230f
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla44476.cs
@@ -0,0 +1,56 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 44476, "[Android] Unwanted margin at top of details page when nested in a NavigationPage")]
+	public class Bugzilla44476 : TestNavigationPage
+	{
+		protected override void Init()
+		{
+			BackgroundColor = Color.Maroon;
+			
+			PushAsync(new MasterDetailPage
+			{
+				Title = "Bugzilla Issue 44476",
+				Master = new ContentPage
+				{
+					Title = "Master",
+					Content = new StackLayout
+					{
+						Children =
+						{
+							new Label { Text = "Master" }
+						}
+					}
+				},
+				Detail = new ContentPage
+				{
+					Title = "Detail",
+					Content = new StackLayout
+					{
+						VerticalOptions = LayoutOptions.FillAndExpand,
+						Children =
+						{
+							new Label { Text = "Detail Page" },
+							new StackLayout
+							{
+								VerticalOptions = LayoutOptions.EndAndExpand,
+								Children =
+								{
+									new Label { Text = "This should be visible." }
+								}
+							}
+						}
+					}
+				},
+			});
+		}
+	}
+}
\ 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 d887d5c3..88ea2c40 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
@@ -137,6 +137,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla44338.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla45743.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla46494.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla44476.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)CarouselAsync.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34561.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla34727.cs" />
@@ -598,4 +599,4 @@
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs b/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs
index ccf01f22..757a98b4 100644
--- a/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/AppCompat/MasterDetailPageRenderer.cs
@@ -116,7 +116,7 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 				{
 					_detailLayout = new MasterDetailContainer(newElement, false, Context)
 					{
-						TopPadding = statusBarHeight,
+						TopPadding = HasAncestorNavigationPage(Element) ? 0 : statusBarHeight,
 						LayoutParameters = new LayoutParams(ViewGroup.LayoutParams.WrapContent, ViewGroup.LayoutParams.WrapContent)
 					};
 
@@ -263,6 +263,16 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 
 		event EventHandler<VisualElementChangedEventArgs> ElementChanged;
 
+		bool HasAncestorNavigationPage(Element element)
+		{
+			if (element.Parent == null)
+				return false;
+			else if (element.Parent is NavigationPage)
+				return true;
+			else
+				return HasAncestorNavigationPage(element.Parent);
+		}
+
 		void HandleMasterPropertyChanged(object sender, PropertyChangedEventArgs e)
 		{
 		}