iOS上类似Spotify的控制中心

Question

这个问题已经问了很多，但是我一直遵循着每个步骤来创建Spotify控制中心。但是我的应用程序甚至没有显示标题和插图。

我播放音频的代码：

@IBAction func play(_ sender: Any) {
    let videoURL = URL(string: "song url")
    player = AVPlayer(url: videoURL!)
    playerViewController = AVPlayerViewController()
    playerViewController.player = player
    self.present(playerViewController, animated: true) {
        self.playerViewController.updatesNowPlayingInfoCenter = true
        self.playerViewController.player!.play()
    }

}

背景播放代码：

   //App enter in forground.
@objc func applicationWillEnterForeground(_ notification: Notification) {
    // If presenting video with AVPlayerViewController
    playerViewController.player = player

}

//App enter in forground.
@objc func applicationDidEnterBackground(_ notification: Notification) {
    // If presenting video with AVPlayerViewController
    playerViewController.player = nil
}

生产Spotify控制中心的进度

我的viewDidLoad()：

override func viewDidLoad() {
    super.viewDidLoad()

    do {
        try AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: [.mixWithOthers, .allowAirPlay])
        print("Playback OK")
        try AVAudioSession.sharedInstance().setActive(true)
        print("Session is Active")
    } catch {
        print(error)
    }
    addPlayerNotifications()
    UIApplication.shared.beginReceivingRemoteControlEvents()
    self.setupNowPlaying()
    self.setupRemoteTransportControls()

}

在viewDidLoad（）内部调用的函数：

 func addPlayerNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(playerItemDidPlayToEnd), name: .AVPlayerItemDidPlayToEndTime, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(applicationWillEnterForeground), name: UIApplication.willEnterForegroundNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(applicationDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil)
}
func setupRemoteTransportControls() {
    // Get the shared MPRemoteCommandCenter
    let commandCenter = MPRemoteCommandCenter.shared()

    // Add handler for Play Command
    commandCenter.playCommand.addTarget { [unowned self] event in
        if self.player.rate == 0.0 {
            self.player.play()
            return .success
        }
        return .commandFailed
    }

    // Add handler for Pause Command
    commandCenter.pauseCommand.addTarget { [unowned self] event in
        if self.player.rate == 1.0 {
            self.player.pause()
            return .success
        }
        return .commandFailed
    }
}
func setupNowPlaying() {
    // Define Now Playing Info
    var nowPlayingInfo = [String : Any]()
    nowPlayingInfo[MPMediaItemPropertyTitle] = "YouTube Videos"

    if let image = UIImage(named: "lockscreen") {
        nowPlayingInfo[MPMediaItemPropertyArtwork] =
            MPMediaItemArtwork(boundsSize: image.size) { size in
                return image
        }
    }
    nowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = player.currentTime().seconds
    nowPlayingInfo[MPMediaItemPropertyPlaybackDuration] = player.currentItem?.duration.seconds
    nowPlayingInfo[MPNowPlayingInfoPropertyPlaybackRate] = player.rate

    // Set the metadata
    MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo
}

框架和功能：

仍然。它没有显示我的图稿，并且控件不起作用：（