Fix Android app bar inset background coloring

src/Controls/src/Core/Platform/Android/Extensions/ToolbarExtensions.cs

@@ -2,6 +2,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Runtime.CompilerServices;
 using Android.Content;
 using Android.Content.Res;
 using Android.Graphics;
@@ -30,6 +31,7 @@ internal static class ToolbarExtensions
 	{
 		static ColorStateList? _defaultTitleTextColor;
 		static int? _defaultNavigationIconColor;
+		static readonly ConditionalWeakTable<AppBarLayout, AppBarBackgroundState> _defaultAppBarBackgrounds = new();
 
 		// Track which ToolbarItem should currently be associated with each MenuItem ID to prevent race conditions
 		// This prevents stale async icon loading callbacks from updating the wrong toolbar items during navigation
@@ -195,6 +197,99 @@ public static void UpdateBarBackground(this AToolbar nativeToolbar, Toolbar tool
 				if (Brush.IsNullOrEmpty(barBackground))
 					nativeToolbar.BackgroundTintMode = null;
 			}
+
+			if (!nativeToolbar.TryUpdateAppBarBackground(toolbar))
+			{
+				nativeToolbar.Post(() => nativeToolbar.TryUpdateAppBarBackground(toolbar));
+			}
+		}
+
+		static bool TryUpdateAppBarBackground(this AToolbar nativeToolbar, Toolbar toolbar)
+		{
+			var appBarLayout = nativeToolbar.Parent?.GetParentOfType<AppBarLayout>();
+			if (appBarLayout is null)
+				return false;
+
+			var backgroundState = GetOrCreateDefaultAppBarBackgroundState(appBarLayout);
+			var barBackground = toolbar.BarBackground;
+
+			if (Brush.IsNullOrEmpty(barBackground))
+			{
+				RestoreDefaultAppBarBackground(appBarLayout, backgroundState);
+				return true;
+			}
+
+			if (barBackground is SolidColorBrush solidColor)
+			{
+				if (solidColor.Color is Color tintColor)
+				{
+					var platformColor = tintColor.ToPlatform();
+					appBarLayout.BackgroundTintMode = null;
+					appBarLayout.BackgroundTintList = null;
+					appBarLayout.Background = new ColorDrawable(platformColor);
+					appBarLayout.StatusBarForeground = new ColorDrawable(platformColor);
+				}
+				else
+				{
+					RestoreDefaultAppBarBackground(appBarLayout, backgroundState);
+				}
+
+				return true;
+			}
+
+			appBarLayout.BackgroundTintMode = null;
+			appBarLayout.BackgroundTintList = null;
+			appBarLayout.UpdateBackground(barBackground);
+			appBarLayout.StatusBarForeground = CloneDrawable(appBarLayout.Background);
+			return true;
+		}
+
+		static AppBarBackgroundState GetOrCreateDefaultAppBarBackgroundState(AppBarLayout appBarLayout)
+		{
+			if (_defaultAppBarBackgrounds.TryGetValue(appBarLayout, out var backgroundState))
+				return backgroundState;
+
+			backgroundState = new AppBarBackgroundState(
+				CloneDrawable(appBarLayout.Background),
+				CloneDrawable(appBarLayout.StatusBarForeground),
+				appBarLayout.BackgroundTintList,
+				appBarLayout.BackgroundTintMode);
+
+			_defaultAppBarBackgrounds.Add(appBarLayout, backgroundState);
+			return backgroundState;
+		}
+
+		static void RestoreDefaultAppBarBackground(AppBarLayout appBarLayout, AppBarBackgroundState backgroundState)
+		{
+			appBarLayout.Background = CloneDrawable(backgroundState.DefaultBackground);
+			appBarLayout.StatusBarForeground = CloneDrawable(backgroundState.DefaultStatusBarForeground);
+			appBarLayout.BackgroundTintMode = backgroundState.DefaultBackgroundTintMode;
+			appBarLayout.BackgroundTintList = backgroundState.DefaultBackgroundTintList;
+		}
+
+		static Drawable? CloneDrawable(Drawable? drawable)
+		{
+			if (drawable is null)
+				return null;
+
+			using var constantState = drawable.GetConstantState();
+			return constantState?.NewDrawable()?.Mutate();
+		}
+
+		sealed class AppBarBackgroundState
+		{
+			public AppBarBackgroundState(Drawable? defaultBackground, Drawable? defaultStatusBarForeground, ColorStateList? defaultBackgroundTintList, PorterDuff.Mode? defaultBackgroundTintMode)
+			{
+				DefaultBackground = defaultBackground;
+				DefaultStatusBarForeground = defaultStatusBarForeground;
+				DefaultBackgroundTintList = defaultBackgroundTintList;
+				DefaultBackgroundTintMode = defaultBackgroundTintMode;
+			}
+
+			public Drawable? DefaultBackground { get; }
+			public Drawable? DefaultStatusBarForeground { get; }
+			public ColorStateList? DefaultBackgroundTintList { get; }
+			public PorterDuff.Mode? DefaultBackgroundTintMode { get; }
 		}
 
 		public static void UpdateIconColor(this AToolbar nativeToolbar, Toolbar toolbar)

src/Controls/tests/DeviceTests/ControlsHandlerTestBase.Android.cs

@@ -159,6 +159,16 @@ protected MaterialToolbar GetPlatformToolbar(IElementHandler handler)
 		protected string GetToolbarTitle(IElementHandler handler) =>
 			GetPlatformToolbar(handler).Title;
 
+		protected AppBarLayout GetPlatformAppBarLayout(IElementHandler handler)
+		{
+			var toolbar = GetPlatformToolbar(handler);
+
+			if (toolbar == null)
+				return null;
+
+			return toolbar.Parent.GetParentOfType<AppBarLayout>();
+		}
+
 		protected MaterialToolbar GetPlatformToolbar(IMauiContext mauiContext)
 		{
 			var navManager = mauiContext.GetNavigationRootManager();
@@ -212,6 +222,31 @@ public bool IsNavigationBarVisible(IMauiContext mauiContext)
 					.LayoutParameters?.Height > 0;
 		}
 
+		protected async Task AssertAppBarTopInsetUsesColor(IElementHandler handler, Color expectedColor)
+		{
+			var toolbar = GetPlatformToolbar(handler);
+			Assert.NotNull(toolbar);
+
+			var appBar = GetPlatformAppBarLayout(handler);
+			Assert.NotNull(appBar);
+
+			var platformColor = expectedColor.ToPlatform();
+
+			await AssertHelpers.AssertEventually(() =>
+			{
+				var backgroundTintList = toolbar.BackgroundTintList;
+
+				return backgroundTintList != null &&
+					backgroundTintList.DefaultColor == platformColor.ToArgb() &&
+					appBar.PaddingTop > 0 &&
+					appBar.Width > 0 &&
+					appBar.Height > appBar.PaddingTop;
+			}, message: "Toolbar background or AppBarLayout top inset did not update.");
+
+			var bitmap = await appBar.ToBitmap(handler.MauiContext);
+			await bitmap.AssertContainsColor(platformColor, rect => new RectF(0, 0, rect.Width, appBar.PaddingTop));
+		}
+
 		protected static WindowInsetsCompat CreateTopCutoutInsets(int statusBarTopInset, int displayCutoutTopInset)
 		{
 			return new WindowInsetsCompat.Builder()

src/Controls/tests/DeviceTests/Elements/NavigationPage/NavigationPageTests.Android.cs

@@ -10,6 +10,7 @@
 using Microsoft.Maui.Controls;
 using Microsoft.Maui.Controls.Handlers;
 using Microsoft.Maui.DeviceTests.Stubs;
+using Microsoft.Maui.Graphics;
 using Microsoft.Maui.Handlers;
 using Microsoft.Maui.Platform;
 using Xunit;
@@ -113,6 +114,30 @@ await AssertEventually(() =>
 			});
 		}
 
+		[Fact(DisplayName = "NavigationPage bar background colors the edge-to-edge top inset area")]
+		public async Task BarBackgroundColorColorsEdgeToEdgeTopInsetArea()
+		{
+			SetupBuilder();
+
+			var expectedColor = Colors.OrangeRed;
+			var rootPage = new ContentPage
+			{
+				Title = "Page Title",
+				Content = new Label { Text = "NavigationPage content" }
+			};
+
+			var navPage = new NavigationPage(rootPage)
+			{
+				BarBackgroundColor = expectedColor
+			};
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Window(navPage), async (handler) =>
+			{
+				await OnLoadedAsync(rootPage);
+				await AssertAppBarTopInsetUsesColor(handler, expectedColor);
+			});
+		}
+
 		[Fact(DisplayName = "NavigationPage push to hidden navigation bar clears app bar inset padding")]
 		public async Task PushingToPageWithoutNavigationBarClearsAppBarInsetPadding()
 		{

src/Controls/tests/DeviceTests/Elements/Shell/ShellTests.Android.cs

@@ -16,6 +16,7 @@
 using Microsoft.Maui.Controls.Platform;
 using Microsoft.Maui.Controls.Platform.Compatibility;
 using Microsoft.Maui.DeviceTests.Stubs;
+using Microsoft.Maui.Graphics;
 using Microsoft.Maui.Handlers;
 using Microsoft.Maui.Platform;
 using Xunit;
@@ -649,6 +650,32 @@ await CreateHandlerAndAddToWindow<ShellHandler>(shell, async (handler) =>
 			});
 		}
 
+		[Fact(DisplayName = "Shell background colors the edge-to-edge top inset area")]
+		public async Task ShellBackgroundColorsEdgeToEdgeTopInsetArea()
+		{
+			SetupBuilder();
+
+			var expectedColor = Colors.OrangeRed;
+			var page = new ContentPage
+			{
+				Title = "Page Title",
+				Content = new Label { Text = "Shell content" }
+			};
+
+			Shell.SetBackgroundColor(page, expectedColor);
+
+			var shell = new Shell
+			{
+				CurrentItem = page
+			};
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(new Controls.Window(shell), async (handler) =>
+			{
+				await OnLoadedAsync(page);
+				await AssertAppBarTopInsetUsesColor(handler, expectedColor);
+			});
+		}
+
 		protected AView GetFlyoutPlatformView(ShellRenderer shellRenderer)
 		{
 			var drawerLayout = GetDrawerLayout(shellRenderer);