ios - 如何判断 AVPlayer 已播放三秒 Swift

Question

我有一个应用程序，其中包含当单元格可见时在 UITableView 中的 UIImageView 中自动播放的视频，而我要做的就是允许该应用程序了解视频何时播放了三秒。我写了这段代码。

    class PostCell: UITableViewCell {

    var player: AVPlayer?
    var playerLayer: AVPlayerLayer?

    var post: Post? {
    didSet {
        updateView()
    }
}

    func updateView() {

    self.viewcount()

    if let videoUrlString = post?.videoUrl, let videoUrl = URL(string: videoUrlString) {
        player = AVPlayer(url: videoUrl)
        playerLayer = AVPlayerLayer(player: player)
        playerLayer?.frame = postImageView.frame
        playerLayer?.frame.size.width = postImageView.frame.size.width
        playerLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
        self.contentView.layer.addSublayer(playerLayer!)

        player?.play()
    }
      func viewcount() {
    if let currentitem = player?.currentItem {
        if currentitem.currentTime() == CMTimeMake(3, 1) {
            print ("VIDEO PLAYED FOR THREE SECONDS")
        }
      }
   }
}

但是一旦视频开始播放，它就不会打印出我的消息。我在网上搜索了帮助，但找不到有关此主题的任何内容。那么有人可以帮助解决我的问题并告诉我我做错了什么吗？

Answer 1

您正在寻找玩家的观察者，这里是您如何检查和跟踪 AVPlayer 的当前位置

这是向单元格添加观察者的函数

private func addObserversForVideoPlayer(cell:CustomCell) {

   let observer =  cell.player?.addPeriodicTimeObserver(forInterval: CMTime.init(seconds: 1, preferredTimescale: 1), queue: .main, using: {[weak self,weak cell] (time) in
        guard let cell = cell else {return}

        if cell.player?.currentItem?.status == .readyToPlay {
            // print("Inside Will DISPLAY\(cell.video.currentTime)")

            let timeDuration : Float64 = CMTimeGetSeconds((cell.player?.currentItem?.asset.duration)!)
            cell.lblDuration.text = self?.getDurationFromTime(time: timeDuration)

            let currentTime : Float64 = CMTimeGetSeconds((cell.player?.currentTime())!)
            cell.lblStart.text = self?.getDurationFromTime(time: currentTime)
            cell.slider.maximumValue = Float(timeDuration.rounded())
            cell.slider.value = Float(currentTime.rounded())

        }
    })
    NotificationCenter.default.addObserver(forName: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: cell.player?.currentItem, queue: .main, using: {[weak cell,weak self]  (notification) in

        if cell?.player != nil {
            cell?.player?.seek(to: kCMTimeZero)
            cell?.player?.play()
        }
    })
}

这样 addPeriodicTimeObserver 将在播放器开始播放时通知您。

并且 NSNotification.Name.AVPlayerItemDidPlayToEndTime 会在 AVPlayer 停止时通知您。

注意1:如果在添加 AVPlayerItemDidPlayToEndTime 时您的 cell.player?.currentItem 为零，则会导致错误，请参阅此 One AVPlayer's AVPlayerItemDidPlayToEndTime action executed for all Currently playing videos ， 如果 。你不需要它就不要添加它:)

注意2:您应该保留observer，这样您就可以在一段时间后将其删除，这样就不会在内存上承受额外的负载

希望对你有帮助