var player: AVQueuePlayer!
  //for sound of assets let sound = NSDataAsset(name: "audio")
  func viewDidLoad() {
        let session = AVAudioSession.sharedInstance()
        try! session.setCategory(AVAudioSessionCategoryPlayAndRecord)
        let item = AVPlayerItem(URL: NSURL(string: "http://incompetech.com/music/royalty-free/mp3-royaltyfree/Motherlode.mp3")!)
        let item2 = AVPlayerItem(URL: NSURL(string: "http://incompetech.com/music/royalty-free/mp3-royaltyfree/Vicious.mp3")!)
        player = AVQueuePlayer(items: [ item, item2])
        player.actionAtItemEnd = .Advance
        
        player.addObserver(self, forKeyPath: "currentItem", options: [.New, .Initial], context: nil)
//        player.addObserver(self, forKeyPath: "currentItem", options: .New ?  .New : .Initial , context: nil)
        player.addPeriodicTimeObserverForInterval(CMTimeMake(1, 100), queue: dispatch_get_main_queue()) {
            [unowned self] time in
            let timeString = String(format: "%02.2f", CMTimeGetSeconds(time))
            if UIApplication.sharedApplication().applicationState == .Active {
                self.titleLabel.text =  timeString
            } else {
                print("Background: \(timeString)")
            }
        }

    }
    
    @IBAction func playPauseAction(sender: UIButton) {
        sender.selected = !sender.selected
        if sender.selected {
            player.play()
        } else {
            player.pause()
        }
    }
    
    override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
        if keyPath == "currentItem" {
                let player = object as? AVPlayer
                let currentItem = player!.currentItem?.asset as? AVURLAsset
                songLabel.text = currentItem!.URL.lastPathComponent ?? "Unknown"
            
        }
    }