fix: chapter list not updating in UI

Author: huynhsontung

Screenbox/Controls/ChapterProgressBar.xaml.cs

@@ -3,9 +3,13 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Collections.Specialized;
 using Windows.Media.Core;
+using Windows.System;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
+using Microsoft.Toolkit.Uwp.UI;
+using Screenbox.Core.Playback;
 using Screenbox.ViewModels;
 
 // The User Control item template is documented at https://go.microsoft.com/fwlink/?LinkId=234236
@@ -66,8 +70,11 @@ public int ChapterIndex
 
         private const double Spacing = 1;
 
+        private readonly DispatcherQueueTimer _chaptersUpdateTimer;
+
         public ChapterProgressBar()
         {
+            _chaptersUpdateTimer = DispatcherQueue.GetForCurrentThread().CreateTimer();
             ProgressItems = new ObservableCollection<ChapterViewModel>();
             this.InitializeComponent();
             SizeChanged += OnSizeChanged;
@@ -76,7 +83,17 @@ public ChapterProgressBar()
         private static void OnChaptersChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
             ChapterProgressBar view = (ChapterProgressBar)d;
-            view.PopulateProgressItems();
+            if (e.NewValue is PlaybackChapterList { Count: 0 } chapterList)
+            {
+                INotifyCollectionChanged observableCollection = chapterList;
+                observableCollection.CollectionChanged -= view.ChaptersOnCollectionChanged;
+                observableCollection.CollectionChanged += view.ChaptersOnCollectionChanged;
+            }
+            else
+            {
+                view.PopulateProgressItems();
+            }
+
         }
 
         private static void OnValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
@@ -106,6 +123,11 @@ private void OnSizeChanged(object sender, SizeChangedEventArgs e)
             }
         }
 
+        private void ChaptersOnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            _chaptersUpdateTimer.Debounce(PopulateProgressItems, TimeSpan.FromMilliseconds(50));
+        }
+
         private void UpdateProgress()
         {
             if (ProgressItems.Count == 1)

Screenbox/Core/Playback/PlaybackChapterList.cs

@@ -1,23 +1,19 @@
 using System;
-using System.Collections;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using Windows.Media.Core;
 using LibVLCSharp.Shared.Structures;
 
 namespace Screenbox.Core.Playback
 {
-    public sealed class PlaybackChapterList : IReadOnlyList<ChapterCue>
+    public sealed class PlaybackChapterList : ReadOnlyObservableCollection<ChapterCue>
     {
-        public int Count => _chapters.Count;
+        private readonly ObservableCollection<ChapterCue> _chapters;
 
-        public ChapterCue this[int index] => _chapters[index];
-
-        private readonly List<ChapterCue> _chapters;
-
-        public PlaybackChapterList()
+        public PlaybackChapterList() : base(new ObservableCollection<ChapterCue>())
         {
-            _chapters = new List<ChapterCue>();
+            _chapters = (ObservableCollection<ChapterCue>)Items;
         }
 
         internal void Load(IEnumerable<ChapterDescription> vlcChapters)
@@ -30,17 +26,10 @@ internal void Load(IEnumerable<ChapterDescription> vlcChapters)
             });
 
             _chapters.Clear();
-            _chapters.AddRange(chapterCues);
-        }
-
-        public IEnumerator<ChapterCue> GetEnumerator()
-        {
-            return _chapters.GetEnumerator();
-        }
-
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return _chapters.GetEnumerator();
+            foreach (ChapterCue chapterCue in chapterCues)
+            {
+                _chapters.Add(chapterCue);
+            }
         }
     }
 }