支持关联视频回退 (#535)

src/App/Controls/App/AppTitleBar.xaml

@@ -81,7 +81,7 @@
             <Button
                 x:Name="BackButton"
                 Style="{StaticResource TitleBarButtonStyle}"
-                Click="OnBackButtonClick"
+                Click="OnBackButtonClickAsync"
                 TabIndex="1">
                 <Button.KeyboardAccelerators>
                     <KeyboardAccelerator Key="Back" IsEnabled="{x:Bind ViewModel.IsBackButtonEnabled, Mode=OneWay}" />

src/App/Controls/App/AppTitleBar.xaml.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.ComponentModel;
+using System.Threading.Tasks;
 using Richasy.Bili.ViewModels.Uwp;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
@@ -43,7 +44,7 @@ public AppViewModel ViewModel
         /// 尝试回退.
         /// </summary>
         /// <returns>是否调用了返回命令.</returns>
-        public bool TryBack()
+        public async Task<bool> TryBackAsync()
         {
             if (BackButton.Visibility != Visibility.Visible)
             {
@@ -52,8 +53,11 @@ public bool TryBack()
 
             if (ViewModel.IsOpenPlayer)
             {
-                ViewModel.IsOpenPlayer = false;
-                return true;
+                if (await PlayerViewModel.Instance.CheckBackAsync())
+                {
+                    ViewModel.IsOpenPlayer = false;
+                    return true;
+                }
             }
             else if (ViewModel.IsShowOverlay)
             {
@@ -110,9 +114,9 @@ private void OnMenuButtonClick(object sender, RoutedEventArgs e)
             ViewModel.IsNavigatePaneOpen = !ViewModel.IsNavigatePaneOpen;
         }
 
-        private void OnBackButtonClick(object sender, RoutedEventArgs e)
+        private async void OnBackButtonClickAsync(object sender, RoutedEventArgs e)
         {
-            TryBack();
+            await TryBackAsync();
         }
 
         private void CheckBackButtonVisibility()

src/App/Pages/RootPage.xaml.cs

@@ -2,6 +2,7 @@
 
 using System.ComponentModel;
 using System.Linq;
+using System.Threading.Tasks;
 using Richasy.Bili.App.Controls;
 using Richasy.Bili.Models.App.Args;
 using Richasy.Bili.ViewModels.Uwp;
@@ -26,9 +27,9 @@ public RootPage()
             this.InitializeComponent();
             this.Loaded += OnLoadedAsync;
             this.CoreViewModel.RequestShowTip += OnRequestShowTip;
-            this.CoreViewModel.RequestBack += OnRequestBack;
+            this.CoreViewModel.RequestBack += OnRequestBackAsync;
             SizeChanged += OnSizeChanged;
-            SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;
+            SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequestedAsync;
         }
 
         /// <summary>
@@ -81,7 +82,7 @@ protected override void OnPointerReleased(PointerRoutedEventArgs e)
             base.OnPointerReleased(e);
         }
 
-        private bool TryBack()
+        private async Task<bool> TryBackAsync()
         {
             if (HolderContainer.Children.Count > 0)
             {
@@ -94,13 +95,13 @@ private bool TryBack()
             }
             else if (CoreViewModel.IsBackButtonEnabled)
             {
-                return TitleBar.TryBack();
+                return await TitleBar.TryBackAsync();
             }
 
             return false;
         }
 
-        private void OnRequestBack(object sender, System.EventArgs e) => TryBack();
+        private async void OnRequestBackAsync(object sender, System.EventArgs e) => await TryBackAsync();
 
         private async void OnLoadedAsync(object sender, RoutedEventArgs e)
         {
@@ -110,9 +111,9 @@ private async void OnLoadedAsync(object sender, RoutedEventArgs e)
             await AccountViewModel.Instance.TrySignInAsync(true);
         }
 
-        private void OnBackRequested(object sender, BackRequestedEventArgs e)
+        private async void OnBackRequestedAsync(object sender, BackRequestedEventArgs e)
         {
-            if (TryBack())
+            if (await TryBackAsync())
             {
                 e.Handled = true;
             }

src/ViewModels/ViewModels.Uwp/Common/PlayerViewModel/PlayerViewModel.Properties.cs

@@ -29,6 +29,7 @@ public partial class PlayerViewModel
         private readonly IFileToolkit _fileToolkit;
         private readonly ILoggerModule _logger;
 
+        private readonly List<string> _historyVideoList;
         private readonly FFmpegInteropConfig _liveFFConfig;
 
         private long _videoId;

src/ViewModels/ViewModels.Uwp/Common/PlayerViewModel/PlayerViewModel.cs

@@ -45,6 +45,7 @@ public PlayerViewModel()
             _videoList = new List<DashItem>();
             _subtitleList = new List<SubtitleItem>();
             _lastReportProgress = TimeSpan.Zero;
+            _historyVideoList = new List<string>();
 
             _liveFFConfig = new FFmpegInteropConfig();
             _liveFFConfig.FFmpegOptions.Add("rtsp-transport", "tcp");
@@ -89,6 +90,32 @@ public void ApplyMediaControl(MediaPlayerElement playerControl)
             BiliPlayer = playerControl;
         }
 
+        /// <summary>
+        /// 检查是否可以返回到主页，或是返回至上一个视频.
+        /// </summary>
+        /// <returns>是否可以返回到主页.</returns>
+        public async Task<bool> CheckBackAsync()
+        {
+            _progressTimer.Stop();
+            if (_historyVideoList.Count > 0)
+            {
+                var lastVideo = _historyVideoList.Last();
+                _historyVideoList.Remove(lastVideo);
+                IsDetailCanLoaded = true;
+                DanmakuViewModel.Instance.Reset();
+                IsPlayInformationError = false;
+
+                await LoadVideoDetailAsync(lastVideo, true);
+
+                _progressTimer.Start();
+                InitDownload();
+                Loaded?.Invoke(this, EventArgs.Empty);
+                return false;
+            }
+
+            return true;
+        }
+
         /// <summary>
         /// 视频加载.
         /// </summary>
@@ -100,10 +127,13 @@ public async Task LoadAsync(object vm, bool isRefresh = false)
             var videoId = string.Empty;
             var seasonId = 0;
 
+            var isReleated = false;
+
             if (vm is VideoViewModel videoVM)
             {
                 videoId = videoVM.VideoId;
                 _videoType = videoVM.VideoType;
+                isReleated = videoVM.IsRelated;
             }
             else if (vm is SeasonViewModel seasonVM)
             {
@@ -128,6 +158,20 @@ public async Task LoadAsync(object vm, bool isRefresh = false)
             DanmakuViewModel.Instance.Reset();
             IsPlayInformationError = false;
 
+            if (!isReleated)
+            {
+                _historyVideoList.Clear();
+            }
+            else
+            {
+                if (_historyVideoList.Contains(AvId))
+                {
+                    _historyVideoList.Remove(AvId);
+                }
+
+                _historyVideoList.Add(AvId);
+            }
+
             switch (_videoType)
             {
                 case VideoType.Video:

src/ViewModels/ViewModels.Uwp/Common/VideoViewModel/VideoViewModel.Properties.cs

@@ -105,6 +105,11 @@ public partial class VideoViewModel
         /// </summary>
         public string SourceCoverUrl { get; set; }
 
+        /// <summary>
+        /// 是否为关联视频.
+        /// </summary>
+        public bool IsRelated { get; set; }
+
         /// <inheritdoc/>
         public override bool Equals(object obj) => obj is VideoViewModel model && VideoId == model.VideoId;
 

src/ViewModels/ViewModels.Uwp/Common/VideoViewModel/VideoViewModel.cs

@@ -227,6 +227,7 @@ public VideoViewModel(Relate relate)
             AdditionalText = relate.Rating.ToString();
             LimitCover(relate.Pic);
             Source = relate;
+            IsRelated = true;
             VideoType = relate.Goto.Equals(ServiceConstants.Av, StringComparison.OrdinalIgnoreCase) ?
                 Models.Enums.VideoType.Video : Models.Enums.VideoType.Pgc;
         }