Merge pull request Flow-Launcher#3797 from Flow-Launcher/theme_mode_api

Add Theme mode API Function

Author: Jack251970

Flow.Launcher.Plugin/EventHandler.cs

@@ -39,7 +39,14 @@ namespace Flow.Launcher.Plugin
     /// <param name="sender"></param>
     /// <param name="args"></param>
     public delegate void VisibilityChangedEventHandler(object sender, VisibilityChangedEventArgs args);
-    
+
+    /// <summary>
+    /// A delegate for when the actual application theme is changed
+    /// </summary>
+    /// <param name="sender"></param>
+    /// <param name="args"></param>
+    public delegate void ActualApplicationThemeChangedEventHandler(object sender, ActualApplicationThemeChangedEventArgs args);
+
     /// <summary>
     /// The event args for <see cref="VisibilityChangedEventHandler"/>
     /// </summary>
@@ -77,4 +84,15 @@ public class FlowLauncherQueryEventArgs
         /// </summary>
         public Query Query { get; set; }
     }
+
+    /// <summary>
+    /// The event args for <see cref="ActualApplicationThemeChangedEventHandler"/>
+    /// </summary>
+    public class ActualApplicationThemeChangedEventArgs : EventArgs
+    {
+        /// <summary>
+        /// <see langword="true"/> if the application has changed actual theme
+        /// </summary>
+        public bool IsDark { get; init; }
+    }
 }

Flow.Launcher.Plugin/Interfaces/IPublicAPI.cs

@@ -501,5 +501,16 @@ public interface IPublicAPI
         /// </summary>
         /// <returns>The time taken to execute the method in milliseconds</returns>
         public Task<long> StopwatchLogInfoAsync(string className, string message, Func<Task> action, [CallerMemberName] string methodName = "");
+
+        /// <summary>
+        /// Representing whether the application is using a dark theme
+        /// </summary>
+        /// <returns></returns>
+        bool IsApplicationDarkTheme();
+
+        /// <summary>
+        /// Invoked when the actual theme of the application has changed. Currently, the plugin will continue to be subscribed even if it is turned off. 
+        /// </summary>
+        event ActualApplicationThemeChangedEventHandler ActualApplicationThemeChanged;
     }
 }

Flow.Launcher/MainWindow.xaml.cs

@@ -20,6 +20,7 @@
 using Flow.Launcher.Infrastructure.Hotkey;
 using Flow.Launcher.Infrastructure.Image;
 using Flow.Launcher.Infrastructure.UserSettings;
+using Flow.Launcher.Plugin;
 using Flow.Launcher.Plugin.SharedCommands;
 using Flow.Launcher.ViewModel;
 using Microsoft.Win32;
@@ -82,7 +83,7 @@ public MainWindow()
             UpdatePosition();
 
             DataObject.AddPastingHandler(QueryTextBox, QueryTextBox_OnPaste);
-            ModernWpf.ThemeManager.Current.ActualApplicationThemeChanged += ThemeManager_ActualApplicationThemeChanged;
+            _viewModel.ActualApplicationThemeChanged += ViewModel_ActualApplicationThemeChanged;
         }
 
         #endregion
@@ -91,7 +92,7 @@ public MainWindow()
 
 #pragma warning disable VSTHRD100 // Avoid async void methods
 
-        private void ThemeManager_ActualApplicationThemeChanged(ModernWpf.ThemeManager sender, object args)
+        private void ViewModel_ActualApplicationThemeChanged(object sender, ActualApplicationThemeChangedEventArgs args)
         {
             _ = _theme.RefreshFrameAsync();
         }
@@ -1020,7 +1021,7 @@ protected virtual void Dispose(bool disposing)
                 {
                     _hwndSource?.Dispose();
                     _notifyIcon?.Dispose();
-                    ModernWpf.ThemeManager.Current.ActualApplicationThemeChanged -= ThemeManager_ActualApplicationThemeChanged;
+                    _viewModel.ActualApplicationThemeChanged -= ViewModel_ActualApplicationThemeChanged;
                 }
 
                 _disposed = true;

Flow.Launcher/PublicAPIInstance.cs

@@ -30,6 +30,7 @@
 using Flow.Launcher.Plugin.SharedModels;
 using Flow.Launcher.ViewModel;
 using JetBrains.Annotations;
+using ModernWpf;
 using Stopwatch = Flow.Launcher.Infrastructure.Stopwatch;
 
 namespace Flow.Launcher
@@ -549,6 +550,17 @@ public long StopwatchLogInfo(string className, string message, Action action, [C
         public Task<long> StopwatchLogInfoAsync(string className, string message, Func<Task> action, [CallerMemberName] string methodName = "") =>
             Stopwatch.InfoAsync(className, message, action, methodName);
 
+        public bool IsApplicationDarkTheme()
+        {
+            return ThemeManager.Current.ActualApplicationTheme == ApplicationTheme.Dark;
+        }
+
+        public event ActualApplicationThemeChangedEventHandler ActualApplicationThemeChanged
+        {
+            add => _mainVM.ActualApplicationThemeChanged += value;
+            remove => _mainVM.ActualApplicationThemeChanged -= value;
+        }
+
         #endregion
 
         #region Private Methods

Flow.Launcher/ViewModel/MainViewModel.cs

@@ -22,6 +22,7 @@
 using Flow.Launcher.Plugin.SharedCommands;
 using Flow.Launcher.Storage;
 using Microsoft.VisualStudio.Threading;
+using ModernWpf;
 
 namespace Flow.Launcher.ViewModel
 {
@@ -154,6 +155,18 @@ public MainViewModel()
 
             RegisterViewUpdate();
             _ = RegisterClockAndDateUpdateAsync();
+
+            ThemeManager.Current.ActualApplicationThemeChanged += ThemeManager_ActualApplicationThemeChanged;
+        }
+
+        private void ThemeManager_ActualApplicationThemeChanged(ThemeManager sender, object args)
+        {
+            ActualApplicationThemeChanged?.Invoke(
+                Application.Current,
+                new ActualApplicationThemeChangedEventArgs()
+                {
+                    IsDark = sender.ActualApplicationTheme == ApplicationTheme.Dark
+                });
         }
 
         private void RegisterViewUpdate()
@@ -703,6 +716,7 @@ private ResultsViewModel SelectedResults
         public bool MainWindowVisibilityStatus { get; set; } = true;
 
         public event VisibilityChangedEventHandler VisibilityChanged;
+        public event ActualApplicationThemeChangedEventHandler ActualApplicationThemeChanged;
 
         public Visibility ClockPanelVisibility { get; set; }
         public Visibility SearchIconVisibility { get; set; }
@@ -1735,6 +1749,7 @@ protected virtual void Dispose(bool disposing)
                     {
                         _resultsViewUpdateTask.Dispose();
                     }
+                    ThemeManager.Current.ActualApplicationThemeChanged -= ThemeManager_ActualApplicationThemeChanged;
                     _disposed = true;
                 }
             }