如何检测AVPlayer实际上开始在swift中播放

Question

您好我已将UISlider最小值设置为0.00.然后我以这种方式设置它的最大值.

self.viewPlayer.layer.addSublayer(playerLayer)
    let duration : CMTime = avPlayer.avPlayer.currentItem!.asset.duration
    let seconds : Float64 = CMTimeGetSeconds(duration)

    sliderBar.maximumValue=Float(seconds)
    sliderBar!.isContinuous = false
    sliderBar!.tintColor = UIColor.green

但我得到了这个例外

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Attempting to set a slider's minimumValue (0.000000) to be larger than the maximumValue (nan)'
enter code here

我知道在prepareForPlay()实际播放之后需要一些时间来真正播放视频.那么如何才能检测到播放器何时真正开始播放视频？请帮我.谢谢

Answer 1

从iOS 10开始,您可以观察timeControlStatus到AVPlayer的属性.它可以.playing.

检查代码:

private func setupAVPlayer() {
    avPlayer.addObserver(self, forKeyPath: "status", options: [.old, .new], context: nil)
    if #available(iOS 10.0, *) {
        avPlayer.addObserver(self, forKeyPath: "timeControlStatus", options: [.old, .new], context: nil)
    } else {
        avPlayer.addObserver(self, forKeyPath: "rate", options: [.old, .new], context: nil)
    }
}

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if object as AnyObject? === avPlayer {
        if keyPath == "status" {
            if avPlayer.status == .readyToPlay {
                avPlayer.play()
            }
        } else if keyPath == "timeControlStatus" {
            if #available(iOS 10.0, *) {
                if avPlayer.timeControlStatus == .playing {
                    videoCell?.muteButton.isHidden = false
                } else {
                    videoCell?.muteButton.isHidden = true
                }
            }
        } else if keyPath == "rate" {
            if avPlayer.rate > 0 {
                videoCell?.muteButton.isHidden = false
            } else {
                videoCell?.muteButton.isHidden = true
            }
        }
    }
}

Answer 2

您可以像这样在AVPlayer的对象上添加观察者

player.addObserver(self, forKeyPath: "status", options: NSKeyValueObservingOptions.new, context: nil)

您可以像这样检查AVPlayer的状态变化

 func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutableRawPointer) {
    if keyPath == "status" {
        print(player.status)
    }
}

Answer 3

以下是我在视频开始时实际知道的事情(而不是它刚刚准备开始时).

斯威夫特4

player = AVPlayer(url: URL(fileURLWithPath: path))
player.addObserver(self, forKeyPath: "rate", options: NSKeyValueObservingOptions.new, context: nil)

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if keyPath == "rate" {
        if player.rate > 0 {
            print("video started")
        }
    }
}