如何在 SwiftUI 中管理 AVPlayer 状态

我有 SwiftUI 中的 URL 列表。当我点击某个项目时，我会呈现一个全屏视频播放器。我有一个@EnvironmentObject它处理一些查看器选项（例如，是否显示时间码）。我还有一个显示和隐藏时间码的切换开关（我只在本例中包含了该切换开关，因为时间码视图并不重要），但每次我更改切换开关时，都会再次创建视图，从而重新设置AVPlayer。这是有道理的，因为我是在视图的初始化程序中创建播放器的。

我想过创建自己的ObserveredObject类包含一个AVPlayer但我不确定如何或在哪里初始化它，因为我需要给它一个 URL，我只能从初始化程序中知道它CustomPlayerView。我也考虑过将播放器设置为@EnvironmentObject但初始化我可能不需要的东西似乎很奇怪（如果用户没有点击 URL 来启动播放器）。

创建一个的正确方法是什么AVPlayer交给 AVKit 的VideoPlayer请？这是我的示例代码：

class ViewerOptions: ObservableObject {
    @Published var showTimecode = false
}

struct CustomPlayerView: View {
    
    @EnvironmentObject var viewerOptions: ViewerOptions
    
    private let avPlayer: AVPlayer
    
    init(url: URL) {
        avPlayer = AVPlayer(url: url)
    }
    
    var body: some View {
        HStack {
            VideoPlayer(player: avPlayer)
            Toggle(isOn: $viewerOptions.showTimecode) { Text("Show Timecode") }
        }
    }
}

您可以在这里采取几种方法。您可以尝试一下，看看哪一个最适合您。

选项1：正如你所说，你可以包裹avPlayer在一个新的ObserveredObject class

class PlayerViewModel: ObservableObject {
    @Published var avPlayer: AVPlayer? = nil
}

class ViewerOptions: ObservableObject {
    @Published var showTimecode = false
}


@main
struct DemoApp: App {
    var playerViewModel = PlayerViewModel()
    var viewerOptions = ViewerOptions()

    var body: some Scene {
        WindowGroup {
            CustomPlayerView(url: URL(string: "Your URL here")!)
                .environmentObject(playerViewModel)
                .environmentObject(viewerOptions)
        }
    }
}

struct CustomPlayerView: View {
    @EnvironmentObject var viewerOptions: ViewerOptions
    @EnvironmentObject var playerViewModel: PlayerViewModel

    init(url: URL) {
        if playerViewModel.avPlayer == nil {
            playerViewModel.avPlayer = AVPlayer(url: url)
        } else {
            playerViewModel.avPlayer?.pause()
            playerViewModel.avPlayer?.replaceCurrentItem(with: AVPlayerItem(url: url))
        }
    }

    var body: some View {
        HStack {
            VideoPlayer(player: playerViewModel.avPlayer)
            Toggle(isOn: $viewerOptions.showTimecode) { Text("Show Timecode") }
        }
    }
}

选项 2：您可以添加avPlayer到你已经存在的班级ViewerOptions作为可选属性，然后在需要时初始化它

class ViewerOptions: ObservableObject {
    @Published var showTimecode = false
    @Published var avPlayer: AVPlayer? = nil
}

struct CustomPlayerView: View {

    @EnvironmentObject var viewerOptions: ViewerOptions

    init(url: URL) {
        if viewerOptions.avPlayer == nil {
            viewerOptions.avPlayer = AVPlayer(url: url)
        } else {
            viewerOptions.avPlayer?.pause()
            viewerOptions.avPlayer?.replaceCurrentItem(with: AVPlayerItem(url: url))
        }
    }

    var body: some View {
        HStack {
            VideoPlayer(player: viewerOptions.avPlayer)
            Toggle(isOn: $viewerOptions.showTimecode) { Text("Show Timecode") }
        }
    }
}

选项 3：让你的avPlayer一个状态对象，这样它的内存将由系统管理，并且不会重新设置它并使其保持活动状态，直到您的视图存在为止。

class ViewerOptions: ObservableObject {
    @Published var showTimecode = false
}

struct CustomPlayerView: View {

    @EnvironmentObject var viewerOptions: ViewerOptions
    @State private var avPlayer: AVPlayer

    init(url: URL) {
        _avPlayer = .init(wrappedValue: AVPlayer(url: url))
    }

    var body: some View {
        HStack {
            VideoPlayer(player: avPlayer)
            Toggle(isOn: $viewerOptions.showTimecode) { Text("Show Timecode") }
        }
    }
}

选项 4：创建您的avPlayer当您需要它时对象然后忘记它（不确定这是否是您的最佳方法，但如果您不需要玩家对象执行自定义操作，那么您可以使用此选项）

class ViewerOptions: ObservableObject {
    @Published var showTimecode = false
}

struct CustomPlayerView: View {

    @EnvironmentObject var viewerOptions: ViewerOptions
    private let url: URL

    init(url: URL) {
        self.url = url
    }

    var body: some View {
        HStack {
            VideoPlayer(player: AVPlayer(url: url))
            Toggle(isOn: $viewerOptions.showTimecode) { Text("Show Timecode") }
        }
    }
}