feat: Support for UISettings.GetColorValue

src/SamplesApp/UITests.Shared/Windows_UI_ViewManagement/UISettingsTests.xaml.cs

@@ -25,7 +25,7 @@ public UISettingsTests()
 
 		public UISettingsTestsViewModel ViewModel { get; private set; }
 
-		private void UISettingsTests_DataContextChanged(FrameworkElement sender, DataContextChangedEventArgs args)
+		private void UISettingsTests_DataContextChanged(DependencyObject sender, DataContextChangedEventArgs args)
 		{
 			ViewModel = (UISettingsTestsViewModel)args.NewValue;
 		}

src/Uno.UI/UI/Xaml/Application.Android.cs

@@ -40,19 +40,6 @@ partial void OnSuspendingPartial()
 			Suspending?.Invoke(this, new Windows.ApplicationModel.SuspendingEventArgs(new Windows.ApplicationModel.SuspendingOperation(DateTime.Now.AddSeconds(30))));
 		}
 
-		private ApplicationTheme GetDefaultSystemTheme()
-		{		
-			if ((int)Build.VERSION.SdkInt >= 28)
-			{
-				var uiModeFlags = Android.App.Application.Context.Resources.Configuration.UiMode & UiMode.NightMask;
-				if (uiModeFlags == UiMode.NightYes)
-				{
-					return ApplicationTheme.Dark;
-				}				
-			}
-			return ApplicationTheme.Light;
-		}
-
 		public void Exit()
 		{
 			Android.OS.Process.KillProcess(Android.OS.Process.MyPid());

src/Uno.UI/UI/Xaml/Application.Skia.cs

@@ -69,16 +69,9 @@ private void Initialize()
 			}
 		}
 
-		private ApplicationTheme GetDefaultSystemTheme() => _coreWindowExtension.GetDefaultSystemTheme();
-
 		internal void ForceSetRequestedTheme(ApplicationTheme theme) => _requestedTheme = theme;
 	}
 
-	internal interface IApplicationExtension
-	{
-		ApplicationTheme GetDefaultSystemTheme();
-	}
-
 	internal interface IApplicationEvents
 	{
 	}

src/Uno.UI/UI/Xaml/Application.cs

@@ -33,6 +33,8 @@
 #else
 using View = Windows.UI.Xaml.UIElement;
 using ViewGroup = Windows.UI.Xaml.UIElement;
+using Uno.Helpers.Theming;
+using Windows.UI.ViewManagement;
 #endif
 
 namespace Windows.UI.Xaml
@@ -161,6 +163,10 @@ internal void InitializationCompleted()
 
 		internal void RaiseRecoverableUnhandledException(Exception e) => UnhandledException?.Invoke(this, new UnhandledExceptionEventArgs(e, false));
 
+		private ApplicationTheme GetDefaultSystemTheme() =>
+			SystemThemeHelper.SystemTheme == SystemTheme.Light ?
+				ApplicationTheme.Light : ApplicationTheme.Dark;
+
 		private IDisposable WritePhaseEventTrace(int startEventId, int stopEventId)
 		{
 			if (_trace.IsEnabled)

src/Uno.UI/UI/Xaml/Application.iOS.cs

@@ -161,19 +161,6 @@ private bool TryParseActivationUri(NSUrl url, out Uri uri)
 				return false;
 			}
 		}
-
-		private ApplicationTheme GetDefaultSystemTheme()
-		{
-			//Ensure the current device is running 12.0 or higher, because `TraitCollection.UserInterfaceStyle` was introduced in iOS 12.0
-			if (UIDevice.CurrentDevice.CheckSystemVersion(12, 0))
-			{
-				if (UIScreen.MainScreen.TraitCollection.UserInterfaceStyle == UIUserInterfaceStyle.Dark)
-				{
-					return ApplicationTheme.Dark;
-				}
-			}
-			return ApplicationTheme.Light;
-		}
 	}
 }
 #endif

src/Uno.UI/UI/Xaml/Application.macOS.cs

@@ -126,29 +126,6 @@ private bool TryHandleUrlActivation(NSUrl[] urls, ApplicationExecutionState prev
 			return handled;
 		}
 
-		/// <summary>
-		/// Based on <see cref="https://forums.developer.apple.com/thread/118974" />
-		/// </summary>
-		/// <returns>System theme</returns>
-		private ApplicationTheme GetDefaultSystemTheme()
-		{
-			var version = DeviceHelper.OperatingSystemVersion;
-			if (version >= new Version(10, 14))
-			{
-				var app = NSAppearance.CurrentAppearance?.FindBestMatch(new string[]
-				{
-					NSAppearance.NameAqua,
-					NSAppearance.NameDarkAqua
-				});
-
-				if (app == NSAppearance.NameDarkAqua)
-				{
-					return ApplicationTheme.Dark;
-				}
-			}
-			return ApplicationTheme.Light;
-		}
-
 		private void SetCurrentLanguage()
 		{
 			var language = NSLocale.PreferredLanguages.ElementAtOrDefault(0);

src/Uno.UI/UI/Xaml/Application.wasm.cs

@@ -103,33 +103,6 @@ private void Initialize()
 			}
 		}
 
-		private ApplicationTheme GetDefaultSystemTheme()
-		{
-			var serializedTheme = WebAssemblyRuntime.InvokeJS("Windows.UI.Xaml.Application.getDefaultSystemTheme()");
-
-			if (serializedTheme != null)
-			{
-				if (Enum.TryParse(serializedTheme, out ApplicationTheme theme))
-				{
-					if (this.Log().IsEnabled(Microsoft.Extensions.Logging.LogLevel.Information))
-					{
-						this.Log().Info("Setting OS preferred theme: " + theme);
-					}
-					return theme;
-				}
-				else
-				{
-					throw new InvalidOperationException($"{serializedTheme} theme is not a supported OS theme");
-				}
-			}
-			//OS has no preference or API not implemented, use light as default
-			if (this.Log().IsEnabled(Microsoft.Extensions.Logging.LogLevel.Information))
-			{
-				this.Log().Info("No preferred theme, using Light instead");
-			}
-			return ApplicationTheme.Light;
-		}
-
 		/// <summary>
 		/// Dispatch method from Javascript
 		/// </summary>

src/Uno.UWP/Helpers/Theming/SystemThemeHelper.Android.cs

@@ -0,0 +1,18 @@
+namespace Uno.Helpers.Theming
+{
+	internal static partial class SystemThemeHelper
+	{
+		private static SystemTheme GetSystemTheme()
+		{
+			if ((int)Build.VERSION.SdkInt >= 28)
+			{
+				var uiModeFlags = Android.App.Application.Context.Resources.Configuration.UiMode & UiMode.NightMask;
+				if (uiModeFlags == UiMode.NightYes)
+				{
+					return ApplicationTheme.Dark;
+				}
+			}
+			return ApplicationTheme.Light;
+		}
+	}
+}

src/Uno.UWP/Helpers/Theming/SystemThemeHelper.cs

@@ -1,6 +1,6 @@
 namespace Uno.Helpers.Theming
 {
-	internal static class SystemThemeHelper
+	internal static partial class SystemThemeHelper
     {
 		internal static SystemTheme SystemTheme => GetSystemTheme();
     }

src/Uno.UWP/Helpers/Theming/SystemThemeHelper.iOS.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Uno.Helpers.Theming
+{
+	internal static partial class SystemThemeHelper
+	{
+		private ApplicationTheme GetDefaultSystemTheme()
+		{
+			//Ensure the current device is running 12.0 or higher, because `TraitCollection.UserInterfaceStyle` was introduced in iOS 12.0
+			if (UIDevice.CurrentDevice.CheckSystemVersion(12, 0))
+			{
+				if (UIScreen.MainScreen.TraitCollection.UserInterfaceStyle == UIUserInterfaceStyle.Dark)
+				{
+					return ApplicationTheme.Dark;
+				}
+			}
+			return ApplicationTheme.Light;
+		}
+	}
+}

src/Uno.UWP/Helpers/Theming/SystemThemeHelper.macOS.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Uno.Helpers.Theming
+{
+	internal static partial class SystemThemeHelper
+	{
+		/// <summary>
+		/// Based on <see cref="https://forums.developer.apple.com/thread/118974" />
+		/// </summary>
+		/// <returns>System theme</returns>
+		private ApplicationTheme GetDefaultSystemTheme()
+		{
+			var version = DeviceHelper.OperatingSystemVersion;
+			if (version >= new Version(10, 14))
+			{
+				var app = NSAppearance.CurrentAppearance?.FindBestMatch(new string[]
+				{
+					NSAppearance.NameAqua,
+					NSAppearance.NameDarkAqua
+				});
+
+				if (app == NSAppearance.NameDarkAqua)
+				{
+					return ApplicationTheme.Dark;
+				}
+			}
+			return ApplicationTheme.Light;
+		}
+	}
+}

src/Uno.UWP/Helpers/Theming/SystemThemeHelper.skia.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Uno.Helpers.Theming
+{
+	internal static partial class SystemThemeHelper
+	{
+
+    }
+
+	internal interface ISystemThemeHelperExtension
+	{
+		SystemTheme GetDefaultSystemTheme();
+	}
+}

src/Uno.UWP/Helpers/Theming/SystemThemeHelper.wasm.cs

@@ -0,0 +1,37 @@
+using System;
+using Uno.Extensions;
+using Uno.Foundation;
+using Uno.Logging;
+
+namespace Uno.Helpers.Theming
+{
+	internal static partial class SystemThemeHelper
+	{
+        private static SystemTheme GetSystemTheme()
+		{
+			var serializedTheme = WebAssemblyRuntime.InvokeJS("Windows.UI.Xaml.Application.getDefaultSystemTheme()");
+
+			if (serializedTheme != null)
+			{
+				if (Enum.TryParse(serializedTheme, out SystemTheme theme))
+				{
+					if (typeof(SystemThemeHelper).Log().IsEnabled(Microsoft.Extensions.Logging.LogLevel.Information))
+					{
+						typeof(SystemThemeHelper).Log().Info("Setting OS preferred theme: " + theme);
+					}
+					return theme;
+				}
+				else
+				{
+					throw new InvalidOperationException($"{serializedTheme} theme is not a supported OS theme");
+				}
+			}
+			//OS has no preference or API not implemented, use light as default
+			if (typeof(SystemThemeHelper).Log().IsEnabled(Microsoft.Extensions.Logging.LogLevel.Information))
+			{
+				typeof(SystemThemeHelper).Log().Info("No preferred theme, using Light instead");
+			}
+			return SystemTheme.Light;
+		}
+	}
+}

src/Uno.UWP/UI/ViewManagement/UISettings.cs

@@ -2,6 +2,7 @@
 #pragma warning disable 114 // new keyword hiding
 using System.Collections.Concurrent;
 using Uno;
+using Uno.Helpers.Theming;
 using Windows.Foundation;
 
 namespace Windows.UI.ViewManagement
@@ -47,7 +48,15 @@ internal static void OnColorValuesChanged()
 
 		public Color GetColorValue(UIColorType desiredColor)
 		{
-			return Colors.Black;
+			var systemTheme = SystemThemeHelper.SystemTheme;
+			return desiredColor switch
+			{
+				UIColorType.Background =>
+					systemTheme == SystemTheme.Light ? Colors.White : Colors.Black,
+				UIColorType.Foreground =>
+					systemTheme == SystemTheme.Light ? Colors.Black : Colors.White,
+				_ => Colors.Transparent
+			};
 		}
 
 		[NotImplemented]