SwiftUI AVQueuePlayer不更新playerItem

Question

我试图显示一个循环视频，然后允许用户点击一个按钮来显示下一个或上一个循环视频。

为什么@Binding不更新这个呢？做这件事的正确/最好的方法是什么？

我正在使用UIViewRepresentable。这是我的密码。

struct Player: UIViewRepresentable {

    var videoFileNames: [String]
    @Binding var currentItem: Int

    func makeUIView(context: Context) -> UIView {
        return PlayerView(frame: .zero, videoFileNames: videoFileNames, currentItem: currentItem)
    }

    func updateUIView(_ uiView: UIView, context: Context) {
    }
}


class PlayerView: UIView {
    private let playerLayer = AVPlayerLayer()
    private var playerLooper: AVPlayerLooper?

    init(frame: CGRect, videoFileNames: [String], currentItem: Int) {
        super.init(frame: frame)

        var playerItems = [AVPlayerItem]()
        let player = AVQueuePlayer(items: playerItems)

        for videoFileName in videoFileNames {
            guard let path = Bundle.main.path(forResource: videoFileName, ofType: "mp4") else {
                return
            }
            let videoURL = NSURL(fileURLWithPath: path)
            let playerItem = AVPlayerItem(url: videoURL as URL)
            playerItems.append(playerItem)
        }

        playerLooper = AVPlayerLooper(player: player, templateItem: playerItems[currentItem])

        player.volume = 0
        player.play()

        playerLayer.player = player
        playerLayer.videoGravity = .resizeAspectFill 

        layer.addSublayer(playerLayer)
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        playerLayer.frame = bounds
    }
}

Answer 1

@Binding中的更改只会导致调用updateUIView，因此您需要适应如下所示的内容(在伪代码中，有点抓挠)

struct Player: UIViewRepresentable {

    var videoFileNames: [String]
    @Binding var currentItem: Int

    private var playerView: PlayerView!

    func makeUIView(context: Context) -> UIView {
        let view = PlayerView(frame: .zero, videoFileNames: videoFileNames, currentItem: currentItem)
        self.playerView = view
        return view
    }

    func updateUIView(_ uiView: UIView, context: Context) {
        self.playerView.currentItem = currentItem // update player !!
    }
}

class PlayerView: UIView {
   var currentItem: Int {
       didSet {
          // .. refresh here internal player
       }
   }

    init(frame: CGRect, videoFileNames: [String], currentItem: Int) {
        super.init(frame: frame)

        self.currentItem = currentItem
        var playerItems = [AVPlayerItem]()

   // .. other code