/// <summary>
/// Handles background task cancellation. Task cancellation happens due to :
/// 1. Another Media app comes into foreground and starts playing music
/// 2. Resource pressure. Your task is consuming more CPU and memory than allowed.
/// In either case, save state so that if foreground app resumes it can know where to start.
/// </summary>
private void OnCanceled(IBackgroundTaskInstance sender, BackgroundTaskCancellationReason reason)
{
// You get some time here to save your state before process and resources are reclaimed
Debug.WriteLine("MyBackgroundAudioTask " + sender.Task.TaskId + " Cancel Requested...");
try
{
//save state
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.CurrentTrack, Playlist.CurrentTrackIndex);
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.Position, BackgroundMediaPlayer.Current.Position.ToString());
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.Time, BackgroundMediaPlayer.Current.NaturalDuration.ToString());
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.BackgroundTaskState, BackgroundAudioConstants.BackgroundTaskCancelled);
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.AppState, Enum.GetName(typeof(ForegroundAppStatus), foregroundAppState));
backgroundtaskrunning = false;
//unsubscribe event handlers
systemmediatransportcontrol.ButtonPressed -= systemmediatransportcontrol_ButtonPressed;
systemmediatransportcontrol.PropertyChanged -= systemmediatransportcontrol_PropertyChanged;
Playlist.TrackChanged -= playList_TrackChanged;
//clear objects task cancellation can happen uninterrupted
playlistManager.ResetCollection((int)ResetType.NormalReset);
playlistManager = null;
// Send message to foreground task (if it's around) that this task was cancelled :(
ValueSet message = new ValueSet {
{ BackgroundAudioConstants.BackgroundTaskCancelled, "" }
};
BackgroundMediaPlayer.SendMessageToForeground(message);
BackgroundMediaPlayer.Shutdown(); // shutdown media pipeline
}
catch (Exception ex)
{
Debug.WriteLine(ex.ToString());
}
deferral?.Complete(); // signals task completion.
Debug.WriteLine("MyBackgroundAudioTask Cancel complete...");
}
/// <summary>
/// Handles background task cancellation. Task cancellation happens due to :
/// 1. Another Media app comes into foreground and starts playing music
/// 2. Resource pressure. Your task is consuming more CPU and memory than allowed.
/// In either case, save state so that if foreground app resumes it can know where to start.
/// </summary>
private void OnCanceled(IBackgroundTaskInstance sender, BackgroundTaskCancellationReason reason)
{
// You get some time here to save your state before process and resources are reclaimed
Debug.WriteLine("MyBackgroundAudioTask " + sender.Task.TaskId + " Cancel Requested...");
try
{
//save state
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.CurrentTrack, Playlist.CurrentTrackIndex);
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.Position, BackgroundMediaPlayer.Current.Position.ToString());
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.Time, BackgroundMediaPlayer.Current.NaturalDuration.ToString());
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.BackgroundTaskState, BackgroundAudioConstants.BackgroundTaskCancelled);
ApplicationSettingsHelper.SaveSettingsValue(BackgroundAudioConstants.AppState, Enum.GetName(typeof(ForegroundAppStatus), foregroundAppState));
backgroundtaskrunning = false;
//unsubscribe event handlers
systemmediatransportcontrol.ButtonPressed -= systemmediatransportcontrol_ButtonPressed;
systemmediatransportcontrol.PropertyChanged -= systemmediatransportcontrol_PropertyChanged;
Playlist.TrackChanged -= playList_TrackChanged;
//clear objects task cancellation can happen uninterrupted
playlistManager.ResetCollection((int)ResetType.NormalReset);
playlistManager = null;
// Send message to foreground task (if it's around) that this task was cancelled :(
ValueSet message = new ValueSet { { BackgroundAudioConstants.BackgroundTaskCancelled, "" } };
BackgroundMediaPlayer.SendMessageToForeground(message);
BackgroundMediaPlayer.Shutdown(); // shutdown media pipeline
}
catch (Exception ex)
{
Debug.WriteLine(ex.ToString());
}
deferral?.Complete(); // signals task completion.
Debug.WriteLine("MyBackgroundAudioTask Cancel complete...");
}