UWP 应用程序闲置一段时间后恢复时崩溃

Question

我多年来一直在开发 UWP 音乐播放器应用程序。我遇到了一个问题，即应用程序在闲置一段不确定的时间后恢复时会崩溃。但是，如果音乐播放器继续播放，该应用程序就可以正常运行。当应用程序在闲置后重新获得焦点时，就会发生崩溃。我无法稳定地重现崩溃，但大多数时候它确实会发生。我只是不知道需要多长时间。 我尝试通过附加调试器来诊断问题，但附加调试器时不会发生崩溃。在

class App : Application

中，我在

Resuming

、

Suspending

和

UnhandledException

方法中添加了try-catch和日志，但仍然无法查明崩溃的原因。我不知道如何进一步解决这个问题。任何关于下一步要采取什么步骤或如何正确

诊断和避免此类崩溃

的建议将不胜感激。 这是我的音乐播放器的部分代码

public class MusicPlayer : IMusicEventListener
{
    public static MediaPlaybackState PlaybackState => Player.PlaybackSession.PlaybackState;
    public static bool IsPlaying => PlaybackState == MediaPlaybackState.Playing;
    public static Playlist NowPlaying => new Playlist(MenuFlyoutHelper.NowPlaying, CurrentPlaylist);
    private static MediaPlaybackList PlaybackList = new MediaPlaybackList() { MaxPlayedItemsToKeepOpen = 1 };
    public static MediaPlayer Player = new MediaPlayer() { Source = PlaybackList };
}

这是我的App类的部分代码

sealed partial class App : Application
{
    public static bool Inited { get; private set; } = false;
    public static List<Action> LoadedListeners = new List<Action>();
    public App()
    {
        this.InitializeComponent();
        this.Suspending += OnSuspending;
        this.Resuming += App_Resuming;
        this.UnhandledException += App_UnhandledException;
    }

    private void App_Resuming(object sender, object e)
    {
        Debug.WriteLine($"sender {sender.GetType()} e {e}");
    }

    protected override void OnLaunched(LaunchActivatedEventArgs e)
    {
        OnLaunched(e, null);
    }

    private void OnSuspending(object sender, SuspendingEventArgs e)
    {
        var deferral = e.SuspendingOperation.GetDeferral();
        try
        {
            TileHelper.ResumeTile();
            ToastHelper.HideToast();
            Save();
            SQLHelper.ClearInactive();
        }
        catch (Exception ex)
        {
            Log.Warn($"OnSuspending exception {ex}");
        }
        deferral.Complete();
    }

    public static async void Save()
    {
        SettingsHelper.Save();
        MusicPlayer.Save();
        await Helper.ClearBackups(10);
    }

    protected override void OnBackgroundActivated(BackgroundActivatedEventArgs args)
    {
        var deferral = args.TaskInstance.GetDeferral();
        switch (args.TaskInstance.Task.Name)
        {
            case ToastHelper.ToastTaskName:
                if (args.TaskInstance.TriggerDetails is Windows.UI.Notifications.ToastNotificationActionTriggerDetail details)
                {
                    // Perform tasks
                    if (Enum.TryParse(typeof(ToastButtonEnum), details.Argument, out object toastButton))
                    {
                        try
                        {
                            HandleBackgroundActivation((ToastButtonEnum)toastButton);
                        }
                        catch (Exception e)
                        {
                            Log.Warn($"HandleBackgroundActivation failed {e}");
                        }
                    }
                }
                break;
        }
        deferral.Complete();
    }

    private async void HandleBackgroundActivation(ToastButtonEnum toastButton)
    {
        switch (toastButton)
        {
            case ToastButtonEnum.Next:
                MusicPlayer.MoveNext();
                if (MusicPlayer.PlayMode == PlayMode.RepeatOne)
                {
                    ToastHelper.HideToast();
                    await ToastHelper.ShowToast(MusicPlayer.CurrentMusic, MusicPlayer.PlaybackState);
                }
                break;
            case ToastButtonEnum.Pause:
                MusicPlayer.Pause();
                break;
            case ToastButtonEnum.Play:
                MusicPlayer.Play();
                break;
            case ToastButtonEnum.SwitchLyricsSourceToMusic:
                await ToastHelper.SwitchLyricsSource(LyricsSource.Music);
                break;
            case ToastButtonEnum.SwitchLyricsSourceToLrcFile:
                await ToastHelper.SwitchLyricsSource(LyricsSource.LrcFile);
                break;
            case ToastButtonEnum.SwitchLyricsSourceToInternet:
                await ToastHelper.SwitchLyricsSource(LyricsSource.Internet);
                break;
        }
    }

    protected override async void OnFileActivated(FileActivatedEventArgs args)
    {
        base.OnFileActivated(args);
        Music music = await Music.LoadFromPathAsync(args.Files[0].Path);
        Log.Info("activate file " + args.Files[0].Path);
        if (music == null)
        {
            Helper.ShowButtonedNotification("CannotReadLocalMusicFile", "Authorize", async (n) =>
            {
                await StorageHelper.AuthorizeFolder();
            });
            return;
        }
        if (args.PreviousExecutionState == ApplicationExecutionState.Running)
        {
            MusicPlayer.AddNextAndPlay(music);
        }
        else
        {
            OnLaunched(null, music);
        }
    }

    private void App_UnhandledException(object sender, Windows.UI.Xaml.UnhandledExceptionEventArgs e)
    {
        Log.Error("App_UnhandledException {0}", e.Exception);
    }

}

Answer 1

Save()

函数中抛出异常，该函数是

async void

而不是

async Task

。因此，它的异常是异步抛出的，并且没有在 OnSuspending 中捕获。因此，解决方案只需在

Save()

函数中捕获问题即可。

private void OnSuspending(object sender, SuspendingEventArgs e)
{
    var deferral = e.SuspendingOperation.GetDeferral();
    try
    {
        TileHelper.ResumeTile();
        ToastHelper.HideToast();
        Save();
        SQLHelper.ClearInactive();
    }
    catch (Exception ex)
    {
        Log.Warn($"OnSuspending exception {ex}");
    }
    deferral.Complete();
}

public static async void Save()
{
    SettingsHelper.Save();
    MusicPlayer.Save();
    await Helper.ClearBackups(10);
}