/// <summary>
/// The Run method is the entry point of a background task.
/// </summary>
/// <param name="taskInstance"></param>
public void Run(IBackgroundTaskInstance taskInstance)
{
Debug.WriteLine("Background Audio Task " + taskInstance.Task.Name + " starting...");
//SystemMediaTransportControls，是按下音量键后顶部弹出的控制音乐播放的控件。
//设置 SystemMediaTransportControls 的各个按键属性以及事件的订阅
systemmediatransportcontrol = SystemMediaTransportControls.GetForCurrentView();
systemmediatransportcontrol.ButtonPressed += systemmediatransportcontrol_ButtonPressed;
systemmediatransportcontrol.PropertyChanged += systemmediatransportcontrol_PropertyChanged;
systemmediatransportcontrol.IsEnabled = true;
systemmediatransportcontrol.IsPauseEnabled = true;
systemmediatransportcontrol.IsPlayEnabled = true;
systemmediatransportcontrol.IsNextEnabled = true;
systemmediatransportcontrol.IsPreviousEnabled = true;
// 关联取消 后台任务处理完成
taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled);
taskInstance.Task.Completed += Taskcompleted;
//读取应用程序状态
var value = ApplicationSettingsHelper.ReadResetSettingsValue(Constants.AppState);
if (value == null)
{
foregroundAppState = ForegroundAppStatus.Unknown;
}
else
{
foregroundAppState = (ForegroundAppStatus)Enum.Parse(typeof(ForegroundAppStatus), value.ToString());
}
//添加在媒体播放器状态发生更改时处理函数
BackgroundMediaPlayer.Current.CurrentStateChanged += Current_CurrentStateChanged;
//Add handlers for playlist trackchanged
//添加 后台播放列表变更时处理函数
Playlist.TrackChanged += playList_TrackChanged;
Playlist.TrackComplete += playList_TrackComplete;
//初始化消息通道 前台发往后台的信息
BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;
//Send information to foreground that background task has been started if app is active
//将信息发送到前景中的后台任务已经启动，如果应用程序被激活
if (foregroundAppState != ForegroundAppStatus.Suspended)
{
ValueSet message = new ValueSet();
message.Add(Constants.BackgroundTaskStarted, "");
BackgroundMediaPlayer.SendMessageToForeground(message);
}
BackgroundTaskStarted.Set();
backgroundtaskrunning = true;
ApplicationSettingsHelper.SaveSettingsValue(Constants.BackgroundTaskState, Constants.BackgroundTaskRunning);
object value11 = ApplicationSettingsHelper.ReadResetSettingsValue(Constants.BackgroundTaskState);
deferral = taskInstance.GetDeferral();
}
/// <summary>
/// The Run method is the entry point of a background task.
/// </summary>
/// <param name="taskInstance"></param>
public void Run(IBackgroundTaskInstance taskInstance)
{
Debug.WriteLine("Background Audio Task " + taskInstance.Task.Name + " starting...");
// Initialize SMTC object to talk with UVC.
//Note that, this is intended to run after app is paused and
//hence all the logic must be written to run in background process
systemmediatransportcontrol = SystemMediaTransportControls.GetForCurrentView();
systemmediatransportcontrol.ButtonPressed += systemmediatransportcontrol_ButtonPressed;
systemmediatransportcontrol.PropertyChanged += systemmediatransportcontrol_PropertyChanged;
systemmediatransportcontrol.IsEnabled = true;
systemmediatransportcontrol.IsPauseEnabled = true;
systemmediatransportcontrol.IsPlayEnabled = true;
systemmediatransportcontrol.IsNextEnabled = true;
systemmediatransportcontrol.IsPreviousEnabled = true;
// Associate a cancellation and completed handlers with the background task.
taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled);
taskInstance.Task.Completed += Taskcompleted;
var value = ApplicationSettingsHelper.ReadResetSettingsValue(Constants.AppState);
if (value == null)
{
foregroundAppState = ForegroundAppStatus.Unknown;
}
else
{
foregroundAppState = (ForegroundAppStatus)Enum.Parse(typeof(ForegroundAppStatus), value.ToString());
}
//Add handlers for MediaPlayer
BackgroundMediaPlayer.Current.CurrentStateChanged += Current_CurrentStateChanged;
//Add handlers for playlist trackchanged
Playlist.TrackChanged += playList_TrackChanged;
//Initialize message channel
BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;
//Send information to foreground that background task has been started if app is active
if (foregroundAppState != ForegroundAppStatus.Suspended)
{
ValueSet message = new ValueSet();
message.Add(Constants.BackgroundTaskStarted, "");
BackgroundMediaPlayer.SendMessageToForeground(message);
}
BackgroundTaskStarted.Set();
backgroundtaskrunning = true;
ApplicationSettingsHelper.SaveSettingsValue(Constants.BackgroundTaskState, Constants.BackgroundTaskRunning);
deferral = taskInstance.GetDeferral();
}
/// <summary>
/// Start playlist and change UVC state
/// </summary>
private void StartPlayback()
{
try
{
if (Playlist.CurrentTrackName == string.Empty)
{
//If the task was cancelled we would have saved the current track and its position. We will try playback from there
var currenttrackname = ApplicationSettingsHelper.ReadResetSettingsValue(Constants.CurrentTrack);
var currenttrackposition = ApplicationSettingsHelper.ReadResetSettingsValue(Constants.Position);
if (currenttrackname != null)
{
if (currenttrackposition == null)
{
// play from start if we dont have position
Playlist.StartTrackAt((string)currenttrackname);
}
else
{
// play from exact position otherwise
Playlist.StartTrackAt((string)currenttrackname, TimeSpan.Parse((string)currenttrackposition));
}
}
else
{
//If we dont have anything, play from beginning of playlist.
Playlist.PlayAllTracks(); //start playback
}
}
else
{
BackgroundMediaPlayer.Current.Play();
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.ToString());
}
}