ios - 获取 slider 的当前时间并播放歌曲

Question

目前我正在 swift 3.0 中开发一个项目，其中我有一个 UISlider 可以跟踪歌曲的进度时间并相应地更新值。因此，随着 ProgressTime 的继续，它会更新其值并且 slider 开始移动，因此一旦 ProgressTime 结束， slider 也会停止。在达到此目的时，我的要求是如果用户将 slider 拖动到特定的随机位置，则从该点播放歌曲。因此，无论用户将 slider 拖动到何处，歌曲都应该播放该特定时间的歌曲。我部分完成的代码如下，我将如何更改函数中的逻辑？

func trackTime() {
    let interval = CMTime(value: 1, timescale: 2)
    player?.addPeriodicTimeObserver(forInterval: interval, queue: DispatchQueue.main, using: { (progressTime) in

        let seconds = CMTimeGetSeconds(progressTime)

        let secondsString = String(format:"%02d", Int(seconds.truncatingRemainder(dividingBy: 60)))
        let minutesString = String(format:"%02d", Int(seconds/60))



        //progress bar and end time
        if let duration = self.player?.currentItem?.asset.duration {

            let durationSeconds = CMTimeGetSeconds(duration)
            let endTimeSeconds = String(format:"%02d", Int(durationSeconds/60))
            self.progressSlider.value = Float(seconds/durationSeconds) 
            self.progressSlider.isContinuous = false

            let newDuration = durationSeconds - seconds

            let endSecondsString = String(format:"%02d", Int(newDuration.truncatingRemainder(dividingBy: 60)))

            self.endtime = "\(endTimeSeconds):\(endSecondsString)"

        }
        self.endTimeLabel.text = self.endtime
        self.startTimeLabel.text = "\(minutesString):\(secondsString)"
    })
}

一旦我按下播放按钮，它的工作原理如下

@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()

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

}

Answer 1

试试这个

添加 slider 选择器方法如下:

  self.progressSlider.addTarget(self, action: Selector("touchUp:"), forControlEvents: [UIControlEvents.TouchUpInside])

slider 的选择器方法

func touchUp(sender:AnyObject?) {
         var showingTime: : CMTime = CMTimeMakeWithSeconds(slider.value, 1);
         player.seek(toTime: showingTime, toleranceBefore: kCMTimeZero, toleranceAfter: kCMTimeZero)    
    }