Question

我使用SwiftUI创建了一个视频播放器，该视频播放器使用imagePickerController加载视频，然后假定一旦检索到就播放视频。我发现检索视频后视频播放器没有刷新。我不确定如何提供适当的@State | @Binding，以刷新它。

我学习了如何使用可用的在线资源对视频播放器进行编码。而且我找到了一种从设备加载视频并将其加载到视频播放器的方法。但是，当我按“播放”按钮时，加载视频后，仅播放声音。我试图将视频播放器设置为@State | @Binding，但是找不到解决方案，因为它似乎不是直观地做到的。

有人可以建议如何使用SwiftUI更新视频播放器的代码吗？

PS 。1）您必须使用实际设备加载视频；和2）滑块尚不起作用。接下来，我将继续工作。

披露：

我已经从在线资源中修改了此代码。大部分工作的原始源代码可以在以下链接中找到：

How to open the ImagePicker in SwiftUI?

https://www.raywenderlich.com/5135-how-to-play-record-and-merge-videos-in-ios-and-swift

https://medium.com/@chris.mash/avplayer-swiftui-part-2-player-controls-c28b721e7e27

<h1>We create Digital Products</h1>
<p></p>
<p>See my work</p>

视频播放器未按预期播放视频，仅播放了向我表明正在播放视频的声音；但是，我看不到它正在播放。它仍然是一个黑匣子。

更新：以下是经过完全编辑的代码，可以按预期工作（滑块除外），下面的评论中对此进行了回答：

import SwiftUI
import AVKit
import PhotosUI
import MobileCoreServices

struct ContentView: View {

    @State var showImagePicker: Bool = false
    @State var url: URL?

    var body: some View {
        ZStack {
            VStack {
                Button(action: {
                    withAnimation {
                        self.showImagePicker.toggle()
                    }
                }) {
                    Text("Show image picker")
                }

                // The video player will needs to be a @State??? as it is not updated with UIView changes but works when no view changes occur.
                PlayerContainerView(player: AVPlayer(url: url ?? URL(string: "https://bitdash-a.akamaihd.net/content/sintel/hls/playlist.m3u8")!))
            }

            if (showImagePicker) {
                ImagePicker(isShown: $showImagePicker, url: $url)
            }
        }
    }
}

struct PlayerView: UIViewRepresentable {
    let player: AVPlayer
    func updateUIView(_ uiView: UIView, context: UIViewRepresentableContext<PlayerView>) {
    }
    func makeUIView(context: Context) -> UIView {
        return PlayerUIView(player: player)
    }
}

class PlayerUIView: UIView {
    private let playerLayer = AVPlayerLayer()
    init(player: AVPlayer) {
        super.init(frame: .zero)

        playerLayer.player = player
        layer.addSublayer(playerLayer)
    }
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    override func layoutSubviews() {
        super.layoutSubviews()
        playerLayer.frame = bounds
    }
}

struct PlayerContainerView : View {

    @State var seekPos = 0.0

    private let player: AVPlayer
    init(player: AVPlayer) {
        self.player = player
    }
    var body: some View {
        VStack {
            PlayerView(player: player)
            PlayerControlsView(player: player)
        }
    }
}

struct PlayerControlsView : View {
    @State var playerPaused = true
    @State var seekPos = 0.0
    let player: AVPlayer
    var body: some View {
        HStack {
            Button(action: {
                self.playerPaused.toggle()
                if self.playerPaused {
                    self.player.pause()
                }
                else {
                    self.player.play()
                }
            }) {
                Image(systemName: playerPaused ? "play" : "pause")
                    .padding(.leading, 20)
                    .padding(.trailing, 20)
            }
            Slider(value: $seekPos, from: 0, through: 1, onEditingChanged: { _ in
                guard let item = self.player.currentItem else {
                    return
                }

                let targetTime = self.seekPos * item.duration.seconds
                self.player.seek(to: CMTime(seconds: targetTime, preferredTimescale: 600))
            })
                .padding(.trailing, 20)
        }
    }
}

struct ImagePicker: UIViewControllerRepresentable {

    @Binding var isShown: Bool
    @Binding var url: URL?

    class Coordinator: NSObject, UINavigationControllerDelegate, UIImagePickerControllerDelegate {

        @Binding var isShown: Bool
        @Binding var url: URL?

        init(isShown: Binding<Bool>, url: Binding<URL?>) {
            $isShown = isShown
            $url = url
        }

        func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {

            let info = convertFromUIImagePickerControllerInfoKeyDictionary(info)
            guard let mediaType = info[convertFromUIImagePickerControllerInfoKey(UIImagePickerController.InfoKey.mediaType)] as? String,
                mediaType == (kUTTypeMovie as String),
                let uiURL = info[convertFromUIImagePickerControllerInfoKey(UIImagePickerController.InfoKey.mediaURL)] as? URL
                else { return }

            url = uiURL
            isShown = false
        }

        func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
            isShown = false
        }

    }

    func makeCoordinator() -> Coordinator {
        return Coordinator(isShown: $isShown, url: $url)
    }

    func makeUIViewController(context: UIViewControllerRepresentableContext<ImagePicker>) -> UIImagePickerController {
        let picker = UIImagePickerController()
        picker.mediaTypes = [kUTTypeMovie as String]
        picker.delegate = context.coordinator
        return picker
    }

    func updateUIViewController(_ uiViewController: UIImagePickerController,
                                context: UIViewControllerRepresentableContext<ImagePicker>) {
    }
}

fileprivate func convertFromUIImagePickerControllerInfoKeyDictionary(_ input: [UIImagePickerController.InfoKey: Any]) -> [String: Any] {
    return Dictionary(uniqueKeysWithValues: input.map {key, value in (key.rawValue, value)})
}

fileprivate func convertFromUIImagePickerControllerInfoKey(_ input: UIImagePickerController.InfoKey) -> String {
    return input.rawValue
}

#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView(showImagePicker: true)
    }
}
#endif

Answer 1

您将updateUIView留为空白。您应该实现它：

func updateUIView(_ uiView: UIView, context: UIViewRepresentableContext<PlayerView>) {
    (uiView as? PlayerUIView)?.updatePlayer(player: player)
}

并将以下方法添加到PlayerUIView中：

func updatePlayer(player: AVPlayer) {
    self.playerLayer.player = player
}

SwiftUI Beta 4：如何正确编码AVPlayer来更新使用ImagePickerController从设备加载的视频？

1 个答案: