适用于音乐应用程序的iOS 12锁定屏幕控件

Question

在iOS 11中，当我锁定iPhone时，我的音乐应用程序将显示锁定屏幕控件。我能够看到当前播放的歌曲以及播放/暂停向前和向后跳过。但是，在升级到Xcode 10 / iOS 12时，我再也看不到锁屏控件仅显示日期和时间...

但是，如果我向上滑动并获得该小部件屏幕（您可以在其中打开飞行模式等），我可以看到正在播放的信息。

这就是我所拥有的

在后台模式下

我已将代码更新为以下内容：

打来了我的viewDidLoad

do {
  try AVAudioSession.sharedInstance().setCategory(.soloAmbient, mode: .default, options: .allowAirPlay)
print("Playback OK")
  try AVAudioSession.sharedInstance().setActive(true)
  print("Session is Active")
} catch {
  print(error)
}


UIApplication.shared.beginReceivingRemoteControlEvents()
self.becomeFirstResponder()

我以前在上一个工作版本中没有以下代码，但我添加了它，因为我发现类似的帖子暗示我这样做

if let songInfo = self.mediaPlayer.nowPlayingItem {
  nowPlayingInfoCenter.nowPlayingInfo = [
    MPMediaItemPropertyTitle: songInfo.title ?? "",
    MPMediaItemPropertyArtist: songInfo.artist ?? "",
    MPMediaItemPropertyArtwork : songInfo.artwork?.image(at: CGSize(width: 400, height: 400)) ?? #imageLiteral(resourceName: "emptyArtworkImage")]
}

我在do try上设置了断点，它不打印任何一种打印功能，并跳过了try

我的代码转换错误吗？

Answer 1

不要忘记设置MPRemoteCommandCenter：

import MediaPlayer

//Use an AVPlayer
var player: AVPlayer!
var playerItem: AVPlayerItem!

您可以在viewDidLoad

中设置AVPlayer

override func viewDidLoad() {
    super.viewDidLoad()

    let path = Bundle.main.path(forResource: "My Heart Will Go On", ofType:"mp3")!
    let url = URL(fileURLWithPath: path)
    playerItem = AVPlayerItem(url: url)
    player = AVPlayer(playerItem: playerItem)
    setupAudioSession()
}

像这样设置音频会话：

func setupAudioSession() {
    do {
        try AVAudioSession.sharedInstance().setCategory(.soloAmbient, mode: .default, options: .allowAirPlay)
        try AVAudioSession.sharedInstance().setActive(true)
    } catch {
        print("Error setting the AVAudioSession:", error.localizedDescription)
    }
}

播放音频文件

func play() {
    player.play()
    setupNowPlaying()
    setupRemoteCommandCenter()
}

设置MPNowPlayingInfoCenter（根据您的代码对其进行自定义）：

func setupNowPlaying() {
    // Define Now Playing Info
    var nowPlayingInfo = [String : Any]()
    nowPlayingInfo[MPMediaItemPropertyTitle] = "My Song"

    nowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = playerItem.currentTime().seconds
    nowPlayingInfo[MPMediaItemPropertyPlaybackDuration] = playerItem.asset.duration.seconds
    nowPlayingInfo[MPNowPlayingInfoPropertyPlaybackRate] = player.rate

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

还有MPRemoteCommandCenter：

func setupRemoteCommandCenter() {
    let commandCenter = MPRemoteCommandCenter.shared();
    commandCenter.playCommand.isEnabled = true
    commandCenter.playCommand.addTarget {event in
        self.player.play()
        return .success
    }
    commandCenter.pauseCommand.isEnabled = true
    commandCenter.pauseCommand.addTarget {event in
        self.player.pause()
        return .success
    }
}