Added playlist view.

Harmonia.WinUI/ViewModels/PlayerViewModel.cs

@@ -1,4 +1,5 @@
 using CommunityToolkit.Mvvm.Input;
+using Harmonia.Core.Engine;
 using Harmonia.Core.Models;
 using Harmonia.Core.Player;
 using Harmonia.WinUI.Caching;
@@ -7,6 +8,7 @@ using Microsoft.UI.Dispatching;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Media.Imaging;
 using System;
+using System.ComponentModel;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Input;
@@ -196,6 +198,7 @@ public partial class PlayerViewModel : ViewModelBase
     {
         _audioPlayer = audioPlayer;
         _audioPlayer.PlayingSongChanged += OnPlayingSongChanged;
+        _audioPlayer.PropertyChanged += OnAudioPlayerPropertyChanged;
 
         _audioBitmapImageCache = audioBitmapCache;
 
@@ -232,6 +235,28 @@ public partial class PlayerViewModel : ViewModelBase
         DispatcherQueue.GetForCurrentThread().TryEnqueue(() => SongImageSource = bitmapImage);
     }
 
+    private void OnAudioPlayerPropertyChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        switch (e.PropertyName)
+        {
+            case nameof(_audioPlayer.State):
+                UpdateTimer();
+                break;
+        }
+    }
+
+    private void UpdateTimer()
+    {
+        if (_audioPlayer.State == AudioPlaybackState.Playing)
+        {
+            _timer.Start();
+        }
+        else
+        {
+            _timer.Stop();
+        }
+    }
+
     private void TickTock(object? sender, object e)
     {
         Position = _audioPlayer.Position;