Ios 在子视图下添加图层

我试图在先前加载的子视图下面添加函数

setupPlayerView

的子层。子视图的加载速度比层快，因为创建层的函数使用的字符串是从另一个类修改而来的，

UIViewController

（我想加载单个视频）。我在stackoverflow上找到了答案，但是

.insertSublayer（player，下面是：self.controlsContainerView.layer）

的建议解决方案对我不起作用。如何确保videolayer依次位于所有其他子视图（如

controlsContainerView

）及其子视图（如

activityIndicatorView

）下

下面是我现在得到的：

class PlayerView: UIView {

var urlString: String? {
    didSet {
        setupPlayerView()
    }
}

override init(frame: CGRect){

    super.init(frame: frame)

    //although the function is called immediately it is not the "lower" than everything else
    setupPlayerView()

    //add subview with controls (e.g. spinner)
    controlsContainerView.frame = frame
    addSubview(controlsContainerView)

    //add to subview and center spinner in subview
    controlsContainerView.addSubview(activityIndicatorView) // (spinner)
    controlsContainerView.addSubview(whiteView)

    //...
}

//... irrelevant code (closures like `activityIndicatorView` and `whiteView`)

//setup video player
func setupPlayerView() {

    if let urlString = self.urlString, let videoURL = NSURL(string: urlString){

        print(urlString)

        //player's video
        if self.player == nil {
            player = AVPlayer(url: videoURL as URL)
        }

        //add sub-layer
        let playerLayer = AVPlayerLayer(player: player)
        playerLayer.frame = self.frame
        self.controlsContainerView.layer.insertSublayer(playerLayer, below: self.controlsContainerView.layer)

        //when are frames actually rendered (when is video loaded so one can remove spinner)
        player?.addObserver(self, forKeyPath: "currentItem.loadedTimeRanges", options: .new, context: nil)

    }

}

对于那些感兴趣的人：我在另一个类（ViewController）中以以下方式更改

urlString

：

---

尝试将其插入索引0，而不是相对于另一个视图。插入子层或添加子视图会导致视图堆栈顶部的添加。尝试在索引0处插入，或者尝试在下面放置新索引的层的索引处插入。效果很好！非常感谢。

videoPlayerView.urlString = videoUrl //videoUrl being some link to a video source