如何检查我的 AVPlayer 是否正在缓冲？

我想检测我的 AVPlayer 是否正在缓冲当前位置，以便我可以显示加载程序或其他内容。但我似乎在 AVPlayer 的文档中找不到任何内容。

你可以观察你的价值观player.currentItem:

playerItem.addObserver(self, forKeyPath: "playbackBufferEmpty", options: .New, context: nil)
playerItem.addObserver(self, forKeyPath: "playbackLikelyToKeepUp", options: .New, context: nil)
playerItem.addObserver(self, forKeyPath: "playbackBufferFull", options: .New, context: nil)

then

override public func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
    if object is AVPlayerItem {
        switch keyPath {
            case "playbackBufferEmpty":
               // Show loader

            case "playbackLikelyToKeepUp":
                // Hide loader

            case "playbackBufferFull":
                // Hide loader
        }
    }
}