xml - 无法加载带有 UICollectionVIewCell 数据的 UIView

Question

我到处寻找解决方案。写这个问题只是想再次碰碰运气。我有一个 collectionViewCell，其中我解析了包含名称和 ID 的 XML URL 数据。现在，当我点击单元格时，我想加载一个带有 AVPlayer 的 UIView。要播放该文件，我必须使用不同的 URL，但使用我在该单元格中解析的 id。这是我的 didSelectItem 函数:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let playerLauncher = PlayerLauncher()
        playerLauncher.showPlayer()
 }

这是我的 PlayerLauncher 文件:

import UIKit

import AVFoundation

class PlayerView: UIView {

    var item: Item?

    override init(frame: CGRect) {
        super.init(frame: frame)

        backgroundColor = UIColor.black

        let id = item?.itemId

        if let url = URL(string: "http://xample.com/play.m3u?id=\(id)") {
            let player = AVPlayer(url: url)
            print(url)
            let playerLayer = AVPlayerLayer(player: player)
            self.layer.addSublayer(playerLayer)
            playerLayer.frame = self.frame

            player.play()
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class PlayerLauncher: NSObject {

        func showPlayer() {

            if let keyWindow = UIApplication.shared.keyWindow {
                let view = UIView(frame: keyWindow.frame)
                view.backgroundColor = UIColor.white

                view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)

                let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
                let playerView = PlayerView(frame: playerFrame)
                view.addSubview(playerView)

                keyWindow.addSubview(view)

                UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
                    view.frame = keyWindow.frame
                }, completion: nil)
            }
        }
    }

我已经从我的 Item NSObject 类中设置了该项目，但在选择单元格后，UIView 加载正常，但不播放文件并显示 id = nil 。我该如何修复它？

更新:所以我稍微更改了代码，我可以打印 id。

以下是我在 didSelectItem 方法中所做的更改:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

        collectionView.deselectItem(at: indexPath, animated: true)

        let playerView = PlayerView()
        playerView.item = items?[indexPath.item]

        let playerLauncher = PlayerLauncher()
        playerLauncher.showPlayer()
 }

之后我更改了 PlayerView 和 PlayerLauncher 类中的一些代码:

import UIKit
import AVFoundation

class PlayerView: UIView {

    var id: String?

    var item: Item? {
        didSet {
            id = item?.itemId
            print(id)
        }
    }

    override init(frame: CGRect) {
        super.init(frame: frame)

        backgroundColor = UIColor.black
    }

    func startPlaying() {

        if let url = URL(string: "http://xample.com/play.m3u?id=\(id)") {
            let player = AVPlayer(url: url)
            print(url)
            let playerLayer = AVPlayerLayer(player: player)
            self.layer.addSublayer(playerLayer)
            playerLayer.frame = self.frame

            player.play()
        }
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class PlayerLauncher: NSObject {

    func showPlayer() {

        if let keyWindow = UIApplication.shared.keyWindow {
            let view = UIView(frame: keyWindow.frame)
            view.backgroundColor = UIColor.white

            view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)

            let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
            let playerView = PlayerView(frame: playerFrame)
            view.addSubview(playerView)

            keyWindow.addSubview(view)

            UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
                view.frame = keyWindow.frame
            }, completion: { (completeAnimation) in
                playerView.startPlaying()
            })
        }
    }
}

现在我可以从 didSet 打印 id，但是在 startPlaying() 方法中，当我选择该项目时，它仍然显示 id = nil 。如何获取 init 或 startPlaying() func 中 didSet 中设置的属性？

Answer 1

您可能希望在选择单元格时检索Item信息。

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let item: Item = itemList[indexPath.item]   // just for instance
    let playerLauncher = PlayerLauncher()
    playerLauncher.showPlayer(item)
}

因此您需要更改您的Player，如下所示:

class PlayerLauncher: NSObject {

    func showPlayer(item: Item) {

        if let keyWindow = UIApplication.shared.keyWindow {
            let view = UIView(frame: keyWindow.frame)
            view.backgroundColor = UIColor.white

            view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)

            let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
            let playerView = PlayerView(frame: playerFrame)
            playerView.item = item // Here
            view.addSubview(playerView)

            keyWindow.addSubview(view)

            UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
                view.frame = keyWindow.frame
            }, completion: { _ in  
                playerView.startPlaying()  // And here
            })
        }
    }
}

在PlayerView中:

class PlayerView: UIView {

    var item: Item?
    var player: AVPlayer?

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = UIColor.black
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func startPlaying() {
        let id = item?.itemId

        if let url = URL(string: "http://xample.com/play.m3u?id=\(id)") {
            self.player = AVPlayer(url: url)
            print(url)
            let playerLayer = AVPlayerLayer(player: self.player)
            self.layer.addSublayer(playerLayer)
            playerLayer.frame = self.frame

            self.player.play()
        }
    }
}

更新:

尝试一下，看看会发生什么:

func startPlaying() {
    guard let id = id else { print("** id is nil"); return }  // here
    print("* item id = \(id)")         // and here

    if let url = URL(string: "http://xample.com/play.m3u?id=\(id)") {
        let player = AVPlayer(url: url)
        print(url)
        let playerLayer = AVPlayerLayer(player: player)
        self.layer.addSublayer(playerLayer)
        playerLayer.frame = self.frame

        player.play()
    }
}

更新#2:

再次，整个代码:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let item = items?[indexPath.item]
    let playerLauncher = PlayerLauncher()
    playerLauncher.showPlayer(item)
}

和:

class PlayerLauncher: NSObject {

    func showPlayer(item: Item) {

        if let keyWindow = UIApplication.shared.keyWindow {
            let view = UIView(frame: keyWindow.frame)
            view.backgroundColor = UIColor.white

            view.frame = CGRect(x: 0, y: keyWindow.frame.height - 50, width: view.frame.width, height: 50)

            let playerFrame = CGRect(x: 0, y: 0, width: keyWindow.frame.width, height: keyWindow.frame.height)
            let playerView = PlayerView(frame: playerFrame)
            playerView.item = item // Here
            view.addSubview(playerView)

            keyWindow.addSubview(view)

            UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
                view.frame = keyWindow.frame
            }, completion: { _ in  
                playerView.startPlaying()  // And here
            })
        }
    }
}

class PlayerView: UIView {

    var id: String?
    var item: Item? {
        didSet {
            id = item?.itemId
            print(id)
        }
    }
    var player: AVPlayer?

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = UIColor.black
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func startPlaying() {
        guard let id = id else { print("** id is nil"); return }  // here
        print("* item id = \(id)")         // and here

        if let url = URL(string: "http://xample.com/play.m3u?id=\(id)") {
            self.player = AVPlayer(url: url)
            print(url)
            let playerLayer = AVPlayerLayer(player: self.player)
            self.layer.addSublayer(playerLayer)
            playerLayer.frame = self.frame

            self.player.play()
        }
    }
}