一、环境

要实现画中画 ios系统必须是 iOS14+

本文开发环境

xcode14.2

二、权限配置

1. 在项目导航器中单击项目，然后单击Signing & Capabilities。
2. 单击 + Capabilit
3. 搜索Background Modes，然后双击将其添加为功能。
4. 在新添加的Background Modes部分，选中Audio, AirPlay, and Picture in Picture复选框。

三、实例

import Foundation
import SwiftUI
import AVKit
struct VideoPlayerView: UIViewControllerRepresentable {
    var videoURL: URL?

       // 创建UIViewController
       func makeUIViewController(context: Context) -> AVPlayerViewController {
           let controller = AVPlayerViewController()
           controller.player = AVPlayer(url: videoURL!)
           controller.allowsPictureInPicturePlayback = true
           controller.delegate = context.coordinator
           return controller
       }

       // 更新UIViewController
       func updateUIViewController(_ uiViewController: AVPlayerViewController, context: Context) {
           uiViewController.player = AVPlayer(url: videoURL!)
           uiViewController.allowsPictureInPicturePlayback = true
           uiViewController.showsPlaybackControls = true // 显示控制层
           if #available(iOS 14.2, *) {
               //进入后台时是否自动打开
//               uiViewController.canStartPictureInPictureAutomaticallyFromInline = true
           } else {
               // Fallback on earlier versions
           }
       }
    func makeCoordinator() -> Coordinator {
            Coordinator(self)
        }

        class Coordinator: NSObject, AVPlayerViewControllerDelegate {
            var playerView: VideoPlayerView

            init(_ playerView: VideoPlayerView) {
                self.playerView = playerView
            }

            func playerViewController(_ playerViewController: AVPlayerViewController, restoreUserInterfaceForPictureInPictureStopWithCompletionHandler completionHandler: @escaping (Bool) -> Void) {
                // 在这里，你可以决定在退出画中画模式后是否保持在当前视图。
                // 这个例子中我们选择保持在当前视图。
                completionHandler(true)
            }
        }
}

struct playView: View {

    var body: some View {
        VStack {
            
            VideoPlayerView(videoURL: URL(string: "http://devimages.apple.com.edgekey.net/streaming/examples/bipbop_4x3/bipbop_4x3_variant.m3u8")!)
                .frame(height: 400)
        }
//        .onAppear {
//            player.play()
//        }
//        .onDisappear {
//            player.pause()
//        }
    }
}

注意：画中画只能在真机上运行，xcode上的模拟器没有画中画功能