[iOS] Fix margin on Shell TitleView (#13319) fixes #13310 fixes #13306

* Fix margin on Shell.TitleView

* - fix ui test

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/ShellTitleView.cs

@@ -1,5 +1,6 @@
 using Xamarin.Forms.CustomAttributes;
 using Xamarin.Forms.Internals;
+using System.Threading.Tasks;
 
 
 #if UITEST
@@ -15,6 +16,7 @@ namespace Xamarin.Forms.Controls.Issues
 #if UITEST
 	[NUnit.Framework.Category(UITestCategories.Shell)]
 	[NUnit.Framework.Category(UITestCategories.TitleView)]
+	[NUnit.Framework.Category(UITestCategories.UwpIgnore)]
 #endif
 	public class ShellTitleView : TestShell
 	{
@@ -27,6 +29,7 @@ namespace Xamarin.Forms.Controls.Issues
 
 			ContentPage createContentPage(string titleView)
 			{
+				Label safeArea = new Label();
 				ContentPage page = new ContentPage()
 				{
 					Content = new StackLayout()
@@ -35,8 +38,10 @@ namespace Xamarin.Forms.Controls.Issues
 						{
 							new Label()
 							{
-								Text = "Click through the tabs and make sure title view changes and doesn't duplicate"
-							}
+								Text = "Tab 1,3, and 4 should have a single visible TitleView. If the TitleView is duplicated or not visible the test has failed.",
+								AutomationId = "Instructions"
+							},
+							safeArea
 						}
 					}
 				};
@@ -58,7 +63,19 @@ namespace Xamarin.Forms.Controls.Issues
 		}
 
 
-#if UITEST && (__IOS__ || __ANDROID__)
+#if UITEST
+
+		[Test]
+		public void TitleViewPositionsCorrectly()
+		{
+			var titleView = RunningApp.WaitForElement("TitleViewId")[0].Rect;
+			var topTab = RunningApp.WaitForElement("page 2")[0].Rect;
+
+			var titleViewBottom = titleView.Y + titleView.Height;
+			var topTabTop = topTab.Y;
+
+			Assert.GreaterOrEqual(topTabTop, titleViewBottom, "Title View is incorrectly positioned behind tabs");
+		}
 
 		[Test]
 		public void NoDuplicateTitleViews()

Xamarin.Forms.Platform.iOS/Renderers/ShellFlyoutContentRenderer.cs

@@ -93,7 +93,7 @@ namespace Xamarin.Forms.Platform.iOS
 			}
 
 			if (header != null)
-				_headerView = new UIContainerView(((IShellController)_shellContext.Shell).FlyoutHeader);
+				_headerView = new ShellFlyoutHeaderContainer(((IShellController)_shellContext.Shell).FlyoutHeader);
 			else
 				_headerView = null;
 

Xamarin.Forms.Platform.iOS/Renderers/ShellFlyoutHeaderContainer.cs

@@ -0,0 +1,28 @@
+using System;
+namespace Xamarin.Forms.Platform.iOS
+{
+	internal class ShellFlyoutHeaderContainer : UIContainerView
+	{
+		public ShellFlyoutHeaderContainer(View view) : base(view)
+		{
+		}
+
+		public override Thickness Margin
+		{
+			get
+			{
+				if (!View.IsSet(View.MarginProperty))
+				{
+					var newMargin = new Thickness(0, (float)Platform.SafeAreaInsetsForWindow.Top, 0, 0);
+
+					if (newMargin != View.Margin)
+					{
+						View.Margin = newMargin;
+					}
+				}
+
+				return View.Margin;
+			}
+		}
+	}
+}

Xamarin.Forms.Platform.iOS/Renderers/UIContainerView.cs

@@ -22,11 +22,7 @@ namespace Xamarin.Forms.Platform.iOS
 			ClipsToBounds = true;
 			view.MeasureInvalidated += OnMeasureInvalidated;
 			MeasuredHeight = double.NaN;
-			_view.BatchCommitted += _view_BatchCommitted;
-		}
-
-		private void _view_BatchCommitted(object sender, Internals.EventArg<VisualElement> e)
-		{
+			Margin = new Thickness(0);
 		}
 
 		internal View View => _view;
@@ -46,22 +42,9 @@ namespace Xamarin.Forms.Platform.iOS
 			return false;
 		}
 
-		public Thickness Margin
+		public virtual Thickness Margin
 		{
-			get
-			{
-				if(!_view.IsSet(View.MarginProperty))
-				{
-					var newMargin = new Thickness(0, (float)Platform.SafeAreaInsetsForWindow.Top, 0, 0);
-
-					if (newMargin != _view.Margin)
-					{
-						_view.Margin = newMargin;
-					}
-				}
-
-				return _view.Margin;
-			}
+			get;
 		}
 
 		void ReMeasure()

Xamarin.Forms.Platform.iOS/Xamarin.Forms.Platform.iOS.csproj

@@ -278,6 +278,7 @@
     <Compile Include="CollectionView\ILoopItemsViewSource.cs" />
     <Compile Include="Renderers\IDisconnectable.cs" />
     <Compile Include="Extensions\BrushExtensions.shared.cs" />
+    <Compile Include="Renderers\ShellFlyoutHeaderContainer.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="Resources\StringResources.ar.resx" />