Code Quality: Fixed an issue where backdrop was not active when resuming from background (#16089)

Author: 0x5bfa

src/Files.App/App.xaml.cs

@@ -159,6 +159,8 @@ async Task ActivateAsync()
 				}
 
 				await AppLifecycleHelper.InitializeAppComponentsAsync();
+
+				AppLifecycleHelper.IsLaunchInitialized = true;
 			}
 		}
 

src/Files.App/Data/Items/WindowEx.cs

@@ -1,6 +1,7 @@
 // Copyright (c) 2024 Files Community
 // Licensed under the MIT License. See the LICENSE.
 
+using Microsoft.UI.Composition.SystemBackdrops;
 using Microsoft.UI.Windowing;
 using Microsoft.UI.Xaml;
 using System.Runtime.InteropServices;
@@ -17,7 +18,7 @@ namespace Files.App.Data.Items
 	/// <summary>
 	/// Represents base <see cref="Window"/> class to extend its features.
 	/// </summary>
-	public unsafe class WindowEx : Window
+	public unsafe class WindowEx : Window, IDisposable
 	{
 		private bool _isInitialized;
 		private readonly WNDPROC _oldWndProc;
@@ -104,7 +105,8 @@ public unsafe WindowEx(int minWidth = 400, int minHeight = 300)
 			var pOldWndProc = PInvoke.SetWindowLongPtr(new(WindowHandle), WINDOW_LONG_PTR_INDEX.GWL_WNDPROC, pNewWndProc);
 			_oldWndProc = Marshal.GetDelegateForFunctionPointer<WNDPROC>(pOldWndProc);
 
-			Closed += (s, e) => { StoreWindowPlacementData(); };
+			Closed += WindowEx_Closed;
+			Activated += WindowEx_Activated; ;
 		}
 
 		private unsafe void StoreWindowPlacementData()
@@ -290,5 +292,22 @@ private LRESULT NewWindowProc(HWND param0, uint param1, WPARAM param2, LPARAM pa
 
 			return PInvoke.CallWindowProc(pfnWndProc, param0, param1, param2, param3);
 		}
+
+		private void WindowEx_Closed(object sender, WindowEventArgs args)
+		{
+			StoreWindowPlacementData();
+		}
+
+		private void WindowEx_Activated(object sender, WindowActivatedEventArgs args)
+		{
+			if (AppLifecycleHelper.IsLaunchInitialized && SystemBackdrop is AppSystemBackdrop appSystemBackdrop)
+				appSystemBackdrop.SystemBackdropConfiguration.IsInputActive = args.WindowActivationState is not WindowActivationState.Deactivated;
+		}
+
+		public void Dispose()
+		{
+			Closed -= WindowEx_Closed;
+			Activated -= WindowEx_Activated;
+		}
 	}
 }

src/Files.App/Helpers/Application/AppLifecycleHelper.cs

@@ -58,6 +58,12 @@ public static class AppLifecycleHelper
 				_ => Constants.AssetPaths.StableLogo
 			});
 
+		/// <summary>
+		/// Gets or sets a value that indicates whether the application is ready to be interacted with.
+		/// This is primarily used for DI container initialization check.
+		/// </summary>
+		public static bool IsLaunchInitialized { get; set; }
+
 		/// <summary>
 		/// Initializes the app components.
 		/// </summary>

src/Files.App/Helpers/UI/AppSystemBackdrop.cs

@@ -16,6 +16,8 @@ internal sealed class AppSystemBackdrop : SystemBackdrop
 		private XamlRoot root;
 		private SystemBackdropTheme? prevTheme = null;
 
+		public SystemBackdropConfiguration SystemBackdropConfiguration { get; set; }
+
 		public AppSystemBackdrop(bool isSecondaryWindow = false)
 		{
 			this.isSecondaryWindow = isSecondaryWindow;
@@ -32,21 +34,21 @@ protected override void OnTargetConnected(ICompositionSupportsSystemBackdrop con
 			base.OnTargetConnected(connectedTarget, xamlRoot);
 			this.target = connectedTarget;
 			this.root = xamlRoot;
-			var configuration = GetDefaultSystemBackdropConfiguration(connectedTarget, xamlRoot);
-			controller = GetSystemBackdropController(userSettingsService.AppearanceSettingsService.AppThemeBackdropMaterial, configuration.Theme);
-			controller?.SetSystemBackdropConfiguration(configuration);
+			SystemBackdropConfiguration = GetDefaultSystemBackdropConfiguration(connectedTarget, xamlRoot);
+			controller = GetSystemBackdropController(userSettingsService.AppearanceSettingsService.AppThemeBackdropMaterial, SystemBackdropConfiguration.Theme);
+			controller?.SetSystemBackdropConfiguration(SystemBackdropConfiguration);
 			controller?.AddSystemBackdropTarget(connectedTarget);
 		}
 
 		protected override void OnDefaultSystemBackdropConfigurationChanged(ICompositionSupportsSystemBackdrop target, XamlRoot xamlRoot)
 		{
 			base.OnDefaultSystemBackdropConfigurationChanged(target, xamlRoot);
-			var configuration = GetDefaultSystemBackdropConfiguration(target, xamlRoot);
-			if (controller is not DesktopAcrylicController acrylicController || acrylicController.Kind != DesktopAcrylicKind.Thin || configuration.Theme == prevTheme)
+			SystemBackdropConfiguration = GetDefaultSystemBackdropConfiguration(target, xamlRoot);
+			if (controller is not DesktopAcrylicController acrylicController || acrylicController.Kind != DesktopAcrylicKind.Thin || SystemBackdropConfiguration.Theme == prevTheme)
 				return;
 
-			prevTheme = configuration.Theme;
-			SetThinAcrylicBackdropProperties(acrylicController, configuration.Theme);
+			prevTheme = SystemBackdropConfiguration.Theme;
+			SetThinAcrylicBackdropProperties(acrylicController, SystemBackdropConfiguration.Theme);
 		}
 
 		protected override void OnTargetDisconnected(ICompositionSupportsSystemBackdrop disconnectedTarget)
@@ -79,9 +81,9 @@ private void OnSettingChanged(object? sender, SettingChangedEventArgs e)
 				case nameof(IAppearanceSettingsService.AppThemeBackdropMaterial):
 					controller?.RemoveAllSystemBackdropTargets();
 					controller?.Dispose();
-					var configuration = GetDefaultSystemBackdropConfiguration(target, root);
-					var newController = GetSystemBackdropController((BackdropMaterialType)e.NewValue!, configuration.Theme);
-					newController?.SetSystemBackdropConfiguration(configuration);
+					SystemBackdropConfiguration = GetDefaultSystemBackdropConfiguration(target, root);
+					var newController = GetSystemBackdropController((BackdropMaterialType)e.NewValue!, SystemBackdropConfiguration.Theme);
+					newController?.SetSystemBackdropConfiguration(SystemBackdropConfiguration);
 					newController?.AddSystemBackdropTarget(target);
 					controller = newController;
 					break;