Question

我正在使用avplayer从远程服务器播放音频文件。当我播放此文件时，首先从URL播放avplayer流，然后播放文件。现在，我只想检测文件流传输何时完成并开始播放。

这是我的代码：

try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)

player = AVPlayer(url: down_url)
player.addObserver(self, forKeyPath: "status", options: NSKeyValueObservingOptions.new, context: nil)
player.volume = 1.0
player.play()


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

我使用此代码进行检测，但是当avplayer开始流式传输时，它仅打印一次“播放器启动”。但是我无法检测到avplayer何时开始播放。

Answer 1

为什么您不尝试下载文件然后在本地播放？您可以使用Alamofire来处理下载，这样您就可以轻松知道下载完成的时间。

Answer 2

注册为播放器项目的status属性的观察者

playerItem.addObserver(self, forKeyPath: #keyPath(AVPlayerItem.status), options: [.old, .new], context: &playerItemContext)

此方法将被调用

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {

    // Only handle observations for the playerItemContext
    guard context == &playerItemContext else {
        super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
        return
    }


    // Observer for Player status
    if keyPath == #keyPath(AVPlayerItem.status) {
        let status: AVPlayerItem.Status
        if let statusNumber = change?[.newKey] as? NSNumber {
            status = AVPlayerItem.Status(rawValue: statusNumber.intValue)!
        } else {
            status = .unknown
        }

        // Switch over status value
        switch status {
        case .readyToPlay:
            // Player item is ready to play.
            player.play()
            playerControlsView.setPlayerControlsReady()
        case .failed:
            // Player item failed. See error.
            print("Fail")
        case .unknown:
            // Player item is not yet ready.
            print("unknown")
        }
    }

}

添加观察者以监视播放器何时播放

NotificationCenter.default.addObserver(self, selector:#selector(self.playerDidFinishPlaying(note:)),name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: player.currentItem)

此方法将在玩家结束播放时调用

@objc func playerDidFinishPlaying(note: NSNotification){
        print("Finished Playing")
}

完成播放器操作后，别忘了删除观察者

NotificationCenter.default.removeObserver(self)

检测文件流已完成并准备与avplayer一起播放

2 个答案: