Question

我在swift 3.0中处理一个项目，我可以通过AVPlayer播放歌曲。我的要求是在歌曲播放结束后跟踪该点并相应地更新播放按钮图像。为此，我使用了NSNotification实例。由于某种原因，它会抛出错误说

＆＃34;由于未捕获的异常终止应用程序＆＃39; NSInvalidArgumentException＆＃39;，原因：＆＃39; - [Project.ViewController finishedPlaying：]：无法识别的选择器发送到实例0x7fda8e928170＆＃39;＆＃34; 。

我在这里想念的是什么？我的代码如下。

 @IBAction func playButtonPressed(_ sender: Any) {

    if newRowSelected == true{
        if(isNewPathSelected){
            print("player")
            let url:URL = savePath!
            playerItem = AVPlayerItem(url: url as URL)
            player=AVPlayer(playerItem: playerItem!)
            let playerLayer=AVPlayerLayer(player: player!)
            playerLayer.frame = CGRect(x: 0, y: 0, width: 10, height: 50) // actually this player layer is not visible
            self.view.layer.addSublayer(playerLayer)
            isNewPathSelected = false
        }

        if player?.rate == 0 // this means if its not playing
        {
            print("Playing")
            player!.play()
            playButton.setImage(UIImage(named: "pause_button"), for: UIControlState.normal)

            trackTime()

            if playerItem != nil {
                print("playerItem")
                NotificationCenter.default.addObserver(self, selector: Selector(("finishedPlaying:")), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: playerItem)

            }

        } else {
            player!.pause()
            playButton.setImage(UIImage(named: "play_button"), for: UIControlState.normal)
        }
    }else{
        showAlert()
    }

}

func finishedPlaying(myNotification:NSNotification) {
    playButton.setImage(UIImage(named: "play_button"), for: UIControlState.normal)

    let stopedPlayerItem: AVPlayerItem = myNotification.object as! AVPlayerItem
    stopedPlayerItem.seek(to: kCMTimeZero)
}

Answer 1

从

更改您的通知服从者

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

进入swift3语法

  NotificationCenter.default.addObserver(self, selector: #selector(self.finishedPlaying(_:)), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: playerItem)

并将方法调用为

@objc func finishedPlaying( _ myNotification:NSNotification) {

}

Answer 2

您可以替换NSNotificationCenter的代码，如下所示

update stg.s3_inventory 
set last_modified_format = translate(last_modified,'TZ',' ','g')::timestamp

Answer 3

var streamPlayer = AVPlayer（）

func playStreamAudio( for audioUrl:String)
    {
        guard streamPlayer.timeControlStatus != .playing else {
            streamPlayer.pause()
            return
        }
        let url = audioUrl //"http://192.168.71.11:7891/rec.wav"
        let playerItem = AVPlayerItem(url: URL(string:url)!)
        streamPlayer = AVPlayer(playerItem:playerItem)
        streamPlayer.rate = 1.0;
        streamPlayer.volume = 1.0
        streamPlayer.play()
    }

如何在AVPlayer中播放歌曲？

3 个答案: