Question

当歌曲在Swift游乐场玩完时，我试图调用一个函数。这是我使用的代码：

NotificationCenter.default.addObserver(self, selector: Selector(("playerDidFinishPlaying:")), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: winMusic)

然而，当歌曲结束播放时，该功能未被调用，我不知道为什么？它显然与iOS应用程序不同。

var winMusic = NSURL(fileURLWithPath: Bundle.main.path(forResource: "win", ofType: "mp3")!)
var winPlayer: AVAudioPlayer? = nil
class Responder : NSObject {
    func playerDidFinishPlaying() {
        print("test")
        /* Nothing printed here */
    }
    func action(sender: UIButton) {
        NotificationCenter.default.addObserver(self, selector: #selector(Responder.playerDidFinishPlaying), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: winMusic)
        NotificationCenter.default.post(name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: nil)
        winPlayer!.play()
    }
}

Answer 1

AVAudioPlayer不发布AVPlayerItemDidPlayToEndTime通知。你需要给玩家一个代表。见https://developer.apple.com/reference/avfoundation/avaudioplayerdelegate/1389160-audioplayerdidfinishplaying

Answer 2

将winPlayer代表设为，

winPlayer?.delegate = self

并实施方法

func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) {
    if flag == true {
        // song finished successfully here
    }
}

您将委托代表由您决定。

如何在Swift Playground中完成歌曲时调用功能

2 个答案: