当一个UIViewController被推走时即使他在内存里保留。。也不能注册成功为第一相映者。。如果想要程序在后台时也接收到系统远端的控制（耳机&iphone最下面默认的播放暂停信号）。。那就需要在工程的基类里覆盖下面的三个函数。

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];     [self becomeFirstResponder]; }

 

- (void) remoteControlReceivedWithEvent: (UIEvent *) receivedEvent {

        if (receivedEvent.type == UIEventTypeRemoteControl) {         switch (receivedEvent.subtype) {             case UIEventSubtypeRemoteControlTogglePlayPause:             {                 [[DMPlayerViewController sharedPubPlayerElement] msg_action_play: nil];                 //NSLog(@"UIEventSubtypeRemoteControlTogglePlayPause");             }                 break;             case UIEventSubtypeRemoteControlPreviousTrack:             {                 [[DMPlayerViewController sharedPubPlayerElement] msg_action_prev: nil];                 //NSLog(@"UIEventSubtypeRemoteControlPreviousTrack");             }                 break;             case UIEventSubtypeRemoteControlNextTrack:             {                 [[DMPlayerViewController sharedPubPlayerElement] msg_action_next: nil];                 //NSLog(@"UIEventSubtypeRemoteControlNextTrack");             }                 break;             default:                 break;         }     } } -(BOOL)canBecomeFirstResponder{     return  YES; }