Swift-为什么在调试视图层次结构内看不到CALayer图像

如何解决Swift-为什么在调试视图层次结构内看不到CALayer图像

我有一个在CALayer中播放的视频。一切正常，但是当我转到Debug View Hierarchy时，视频播放的CALayer总是空白。

为什么在CALayer内的Debug View Hierarchy上看不到视频帧？

class AVPlayerView: UIView {

    var playerLayer: CALayer?

    override func layoutSublayers(of layer: CALayer) {
        super.layoutSublayers(of: layer)
    
        playerLayer?.frame = self.bounds
    }
}

lazy var avPlayerView: AVPlayerView = {
    let playerView = AVPlayerView()
    playerView.tag = 2
    return playerView
}()

func setPlayerAndplayerLayer(url: URL) {

    let asset = AVAsset(url: url)
    playerItem = AVPlayerItem(asset: asset)
    player = AVPlayer(playerItem: playerItem)
    contentView.addSubview(avPlayerView)
    avPlayerView.frame = self.bounds
    playerLayer.frame = avPlayerView.bounds
    avPlayerView.layer.addSublayer(playerLayer!)
    avPlayerView.playerLayer = playerLayer
    avPlayerView.layoutIfNeeded()
}