+ (UIBackgroundTaskIdentifier)backgroundPlayerID:(UIBackgroundTaskIdentifier)backTaskId{    // 1. 設置并激活音頻會話類別       AVAudioSession *session = [AVAudioSession sharedInstance];    [session AVAudioSessionCategoryPlayback error:nil];    [session setActive:YES error:nil];    // 2. 允許應用程序接收遠程控制    [[UIapplication sharedApplication] beginReceivingRemoteControlEvents];    // 3. 設置后臺任務ID      UIBackgroundTaskIdentifier newTaskId = UIBackgroundTaskInvalid;    newTaskId = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil];    if (newTaskId != UIBackgroundTaskInvalid && backTaskId != UIBackgroundTaskInvalid) {        [[UIApplication sharedApplication] endBackgroundTask:backTaskId];    }    return newTaskId;}

//后臺播放音頻設置  AVAudioSession *session = [AVAudioSession sharedInstance];    [session setActive:YES error:nil];    [session setCategory:AVAudioSessionCategoryPlayback error:nil];     //讓app支持接受遠程控制事件  [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];  

// 后臺播放任務IdUIBackgroundTaskIdentifier  _bgTaskId;// 設置音頻會話，允許后臺播放_bgTaskId = [SoundTool backgroundPlayerID:_bgTaskId];