为什么无法在 Swift 中使用AVFoundation扫描 QRCode

我已经在Xcode14.2中使用AVFoundation实现了QRCode扫描器，代码如下

code:当我在设备中运行此代码时，摄像头打开，但无法扫描二维码.为什么？我哪里错了.如何使用AVFoundation扫描二维码.请帮帮我.

我在下面的代码中遗漏了什么吗？请给我带路

如果我在模拟器中运行，它会显示您正在模拟器中运行

class QRCodeScannerVC: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

var captureSession: AVCaptureSession!
var previewLayer: AVCaptureVideoPreviewLayer!

override func viewDidLoad() {
    super.viewDidLoad()
    
    view.backgroundColor = UIColor.black
    captureSession = AVCaptureSession()
    
    guard let videoCaptureDevice = AVCaptureDevice.default(for: AVMediaType.video) else{
        print("you are running in simulator")
        return
    }
    let videoInput: AVCaptureDeviceInput
    
    do {
        videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice)
    } catch {
        return
    }
    
    if (captureSession.canAddInput(videoInput)) {
        captureSession.addInput(videoInput)
    } else {
        failed();
        return;
    }
    
    let metadataOutput = AVCaptureMetadataOutput()
    
    if (captureSession.canAddOutput(metadataOutput)) {
        captureSession.addOutput(metadataOutput)
        
        metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
        metadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.ean8, AVMetadataObject.ObjectType.ean13, AVMetadataObject.ObjectType.pdf417]
    } else {
        failed()
        return
    }
    
    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession);
    previewLayer.frame = view.layer.bounds;
    previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill;
    view.layer.addSublayer(previewLayer);
    
    captureSession.startRunning();
}

func failed() {
    let ac = UIAlertController(title: "Scanning not supported", message: "Your device does not support scanning a code from an item. Please use a device with a camera.", preferredStyle: .alert)
    ac.addAction(UIAlertAction(title: "OK", style: .default))
    present(ac, animated: true)
    captureSession = nil
    print("in simulator")
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    
    if (captureSession?.isRunning == false) {
        DispatchQueue.global(qos: .background).async {
            self.captureSession.startRunning();
        }
    }
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    
    if (captureSession?.isRunning == true) {
        captureSession.stopRunning();
    }
}

func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection){
    captureSession.stopRunning()
    
    if let metadataObject = metadataObjects.first {
        let readableObject = metadataObject as! AVMetadataMachineReadableCodeObject;
        
        AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
        found(code: readableObject.stringValue!);
    }
    dismiss(animated: true)
}

func found(code: String) {
    print(code)
    self.showSingleButtonAlertWithoutAction(title: code)
}
override var prefersStatusBarHidden: Bool {
    return true
}
override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    return .portrait
}
}