同时有效作用区域：AppleTV、AirPlay投射，耳机线控，车载系统显示等位置
关键词：RemoteControl
设定代码
RemoteComtrol会以事件方式通知到整个responder chain，通常在responder chain的末端UIApplication（Swift下使用@UIApplicationMain进行标记）中实现RemoteComtrol事件处理最为合理。
UIApplication.sharedApplication().beginReceivingRemoteControlEvents()
override func remoteControlReceivedWithEvent(event: UIEvent?){
switch event {
case is UIEventSubtypeRemoteControlPlay:
// play
case is UIEventSubtypeRemoteControlPause:
// pause
case is UIEventSubtypeRemoteControlStop:
// stop
}
}
UIEventSubtype 中定义的其他枚举事件类型
UIEventSubtypeRemoteControlPlay
UIEventSubtypeRemoteControlPause
UIEventSubtypeRemoteControlStop
UIEventSubtypeRemoteControlTogglePlayPause
UIEventSubtypeRemoteControlNextTrack
UIEventSubtypeRemoteControlPreviousTrack
UIEventSubtypeRemoteControlBeginSeekingBackward
UIEventSubtypeRemoteControlEndSeekingBackward
UIEventSubtypeRemoteControlBeginSeekingForward
UIEventSubtypeRemoteControlEndSeekingForward
