在swift 5中观察屏幕录制

import ReplayKit

class ViewController: UIViewController, RPScreenRecorderDelegate {
    var screenRecorder: RPScreenRecorder?

    override func viewDidLoad() {
        super.viewDidLoad()
        
        screenRecorder = RPScreenRecorder.shared()
        screenRecorder?.delegate = self
    }
    
    // 开始屏幕录制
    func startRecording() {
        screenRecorder?.startRecording { error in
            if let error = error {
                print("屏幕录制开始失败: \(error.localizedDescription)")
            } else {
                print("屏幕录制已开始")
            }
        }
    }
    
    // 停止屏幕录制
    func stopRecording() {
        screenRecorder?.stopRecording { previewViewController, error in
            if let error = error {
                print("屏幕录制停止失败: \(error.localizedDescription)")
            } else if let previewViewController = previewViewController {
                previewViewController.previewControllerDelegate = self
                self.present(previewViewController, animated: true, completion: nil)
            }
        }
    }
    
    // 录制状态发生变化时的回调
    func screenRecorderDidChangeAvailability(_ screenRecorder: RPScreenRecorder) {
        if screenRecorder.isAvailable {
            print("屏幕录制可用")
        } else {
            print("屏幕录制不可用")
        }
    }
}

extension ViewController: RPPreviewViewControllerDelegate {
    // 预览界面关闭时的回调
    func previewControllerDidFinish(_ previewController: RPPreviewViewController) {
        dismiss(animated: true, completion: nil)
    }
}