[Shell,Android] Allow transparent background on Shell Header

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

@@ -26,11 +26,14 @@ public ShellFlyoutBackground()
 
 		protected override void Init()
 		{
-			AddFlyoutItem(CreateContentPage(), "Item 1");
-			AddFlyoutItem(CreateContentPage(), "Item 2");
+			for (int i = 0; i < 20; i++)
+			{
+				AddFlyoutItem(CreateContentPage(), $"Item {i}");
+			}
 
 			FlyoutBackgroundImage = "photo.jpg";
 			FlyoutBackgroundImageAspect = Aspect.AspectFill;
+			FlyoutVerticalScrollMode = ScrollMode.Enabled;
 		}
 
 		ContentPage CreateContentPage()
@@ -148,6 +151,52 @@ ContentPage CreateContentPage()
 							}
 						}),
 						AutomationId = "ToggleHeaderFooter"
+					},
+					new Button()
+					{
+						Text = "Toggle Header/Footer Transparent",
+						Command = new Command(() =>
+						{
+							if (FlyoutHeader == null)
+							{
+								FlyoutFooter =
+									new Label()
+									{
+										Text = "The FOOTER",
+										TextColor = Color.Blue,
+										HeightRequest = 50
+									};
+
+								FlyoutHeader =
+								new StackLayout
+								{
+									Orientation = StackOrientation.Horizontal,
+									HeightRequest = 100,
+									Children = {
+										new Label()
+										{
+											Text = "The HEADER",
+											FontSize = 25,
+											FontAttributes = FontAttributes.Bold,
+											VerticalTextAlignment = TextAlignment.Center,
+											TextColor = Color.Blue,
+										},
+										new Button()
+										{
+											Text = "OK",
+											FontSize = 25,
+											TextColor = Color.Green,
+											Command = new Command(() => DisplayAlert("Button", "ThisButtonWorks", "OK"))
+										}
+									}
+								};
+							}
+							else
+							{
+								FlyoutHeader = FlyoutFooter = null;
+							}
+						}),
+						AutomationId = "ToggleHeaderFooterTransparent"
 					}
 				}
 			};

Xamarin.Forms.Platform.Android/Renderers/ContainerView.cs

@@ -62,13 +62,12 @@ protected override void OnLayout(bool changed, int l, int t, int r, int b)
 
 			var width = Context.FromPixels(r - l);
 			var height = Context.FromPixels(b - t);
-
-			_shellViewRenderer.LayoutView(width, height);
+			LayoutView(0, 0, width, height);
 		}
 
 		protected virtual void LayoutView(double x, double y, double width, double height)
 		{
-			View?.Layout(new Rectangle(x, y, width, height));
+			_shellViewRenderer.LayoutView(width, height);
 		}
 
 		protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)

Xamarin.Forms.Platform.Android/Renderers/ShellFlyoutTemplatedContentRenderer.cs

@@ -549,19 +549,8 @@ void UpdateElevation()
 
 			protected override void LayoutView(double x, double y, double width, double height)
 			{
-				var context = Context;
-				var paddingLeft = context.FromPixels(PaddingLeft);
-				var paddingTop = context.FromPixels(PaddingTop);
-				var paddingRight = context.FromPixels(PaddingRight);
-				var paddingBottom = context.FromPixels(PaddingBottom);
-
-				width -= paddingLeft + paddingRight;
-				height -= paddingTop + paddingBottom;
-
 				UpdateElevation();
-
-				if (View != null)
-					View.Layout(new Rectangle(paddingLeft, paddingTop, width, height));
+				base.LayoutView(x, y, width, height);
 			}
 
 			protected override void Dispose(bool disposing)

Xamarin.Forms.Platform.Android/Resources/Layout/FlyoutContent.axml

@@ -12,6 +12,8 @@
 			android:id="@+id/flyoutcontent_appbar"
 			android:layout_width="match_parent"
 			android:layout_height="wrap_content"
+			android:background="@null"
+			app:elevation="0dp"
 			android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />
 
 </xamarin.forms.platform.android.ShellFlyoutLayout>