Question

我最近决定在我的应用中为播客添加背景音频播放支持。我已经完成了大部分工作但是，BackgroundMediaPlayer的SystemTransportControls中的暂停按钮似乎没有做任何事情。

这是我的后台音频任务类文件：

public sealed class AudioPlayer : IBackgroundTask
{
    private BackgroundTaskDeferral _deferral;
    public void Run(IBackgroundTaskInstance taskInstance)
    {
        _deferral = taskInstance.GetDeferral();

        var control = BackgroundMediaPlayer.Current.SystemMediaTransportControls;
        control.IsEnabled = true;
        control.IsPauseEnabled = true;
        control.IsPlayEnabled = true;
        control.IsNextEnabled = false;
        control.IsPreviousEnabled = false;

        taskInstance.Canceled += TaskInstance_Canceled;

        BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;
    }

    private void TaskInstance_Canceled(IBackgroundTaskInstance sender, BackgroundTaskCancellationReason reason)
    {
        BackgroundMediaPlayer.Shutdown();
        _deferral.Complete();
    }

    void BackgroundMediaPlayer_MessageReceivedFromForeground(object sender, MediaPlayerDataReceivedEventArgs e)
    {
        object obj;
        e.Data.TryGetValue("MessageBody", out obj);

        string url = (string)obj;
        url = url.Replace("\"", "");
        var source = MediaSource.CreateFromUri(new Uri(url, UriKind.Absolute));

        var list = new MediaPlaybackList();
        list.Items.Add(new MediaPlaybackItem(source));

        BackgroundMediaPlayer.Current.Source = list;
        BackgroundMediaPlayer.Current.Play();
    }
}

重要的是要注意音频确实在后台开始播放，但我没有能力暂停音频。

谢谢， P上。

Answer 1

要对SystemMediaTransportControls（SMTC）做出反应并处理每个通用音量控制（UVC）按钮：播放，暂停，下一个和上一个，我们需要处理Run方法中的SystemMediaTransportControls.ButtonPressed event，如下所示：< / p>

public void Run(IBackgroundTaskInstance taskInstance)
{
    var control = BackgroundMediaPlayer.Current.SystemMediaTransportControls;
    control.ButtonPressed += control_ButtonPressed;
    ...
}

在control_ButtonPressed方法中，处理不同的按钮，如：

private void control_ButtonPressed(SystemMediaTransportControls sender, SystemMediaTransportControlsButtonPressedEventArgs args)
{
    switch (args.Button)
    {
        case SystemMediaTransportControlsButton.Play:
            //Todo with play
            break;
        case SystemMediaTransportControlsButton.Pause:
            //Todo with pause
            break;
        case SystemMediaTransportControlsButton.Next:
            //Todo with skip to next;
            break;
        case SystemMediaTransportControlsButton.Previous:
            //Todo with skip to previous;
            break;
    }
}

有关完整示例，请参阅GitHub上的官方Background audio sample，尤其是MyBackgroundAudioTask class。还有一个非常好的帖子将指导您设置背景音频，对设备媒体控件做出反应，与后台媒体播放器通信以及管理播放列表。阅读更多The Basics of Background Audio。

Windows 10 BackgroundMediaPlayer SystemTransportControls暂停按钮不起作用

1 个答案: