如何在摄像机视图中从后向前切换摄像机View Controller？

Question

我试图通过从我们的相机捕捉图像来制作像Instagram这样的相机视图，我在这里按照本教程https://www.youtube.com/watch?v=-O8WBZNIAN8&t=64s

这是使用的代码：

class ViewController: UIViewController {

    @IBOutlet weak var cameraButton: UIButton!

    var captureSession = AVCaptureSession()

    var backCamera: AVCaptureDevice?
    var frontCamera: AVCaptureDevice?
    var currentDevice: AVCaptureDevice?

    var photoOutput: AVCapturePhotoOutput?

    var cameraPreviewLayer:AVCaptureVideoPreviewLayer?

    var image: UIImage?

    var toggleCameraGestureRecognizer = UISwipeGestureRecognizer()

    var zoomInGestureRecognizer = UISwipeGestureRecognizer()
    var zoomOutGestureRecognizer = UISwipeGestureRecognizer()

    override func viewDidLoad() {
        super.viewDidLoad()
        setupCaptureSession()
        setupDevice()
        setupInputOutput()
        setupPreviewLayer()
        captureSession.startRunning()

        toggleCameraGestureRecognizer.direction = .up
        toggleCameraGestureRecognizer.addTarget(self, action: #selector(self.switchCamera))
        view.addGestureRecognizer(toggleCameraGestureRecognizer)

        // Zoom In recognizer
        zoomInGestureRecognizer.direction = .right
        zoomInGestureRecognizer.addTarget(self, action: #selector(zoomIn))
        view.addGestureRecognizer(zoomInGestureRecognizer)

        // Zoom Out recognizer
        zoomOutGestureRecognizer.direction = .left
        zoomOutGestureRecognizer.addTarget(self, action: #selector(zoomOut))
        view.addGestureRecognizer(zoomOutGestureRecognizer)
        styleCaptureButton()
    }


    func styleCaptureButton() {
        cameraButton.layer.borderColor = UIColor.white.cgColor
        cameraButton.layer.borderWidth = 5
        cameraButton.clipsToBounds = true
        cameraButton.layer.cornerRadius = min(cameraButton.frame.width, cameraButton.frame.height) / 2
    }

    func setupCaptureSession() {
        captureSession.sessionPreset = AVCaptureSession.Preset.photo
    }

    func setupDevice() {
        let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [AVCaptureDevice.DeviceType.builtInWideAngleCamera], mediaType: AVMediaType.video, position: AVCaptureDevice.Position.unspecified)
        let devices = deviceDiscoverySession.devices

        for device in devices {
            if device.position == AVCaptureDevice.Position.back {
                backCamera = device
            } else if device.position == AVCaptureDevice.Position.front {
                frontCamera = device
            }
        }
        currentDevice = backCamera
    }

    func setupInputOutput() {
        do {

            let captureDeviceInput = try AVCaptureDeviceInput(device: currentDevice!)
            captureSession.addInput(captureDeviceInput)
            photoOutput = AVCapturePhotoOutput()
            photoOutput!.setPreparedPhotoSettingsArray([AVCapturePhotoSettings(format: [AVVideoCodecKey : AVVideoCodecType.jpeg])], completionHandler: nil)
            captureSession.addOutput(photoOutput!)


        } catch {
            print(error)
        }
    }

    func setupPreviewLayer() {
        self.cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        self.cameraPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
        self.cameraPreviewLayer?.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
        self.cameraPreviewLayer?.frame = view.frame

        self.view.layer.insertSublayer(self.cameraPreviewLayer!, at: 0)
    }


    @objc func switchCamera() {
        captureSession.beginConfiguration()

        // Change the device based on the current camera
        let newDevice = (currentDevice?.position == AVCaptureDevice.Position.back) ? frontCamera : backCamera

        // Remove all inputs from the session
        for input in captureSession.inputs {
            captureSession.removeInput(input as! AVCaptureDeviceInput)
        }

        // Change to the new input
        let cameraInput:AVCaptureDeviceInput
        do {
            cameraInput = try AVCaptureDeviceInput(device: newDevice!)
        } catch {
            print(error)
            return
        }

        if captureSession.canAddInput(cameraInput) {
            captureSession.addInput(cameraInput)
        }

        currentDevice = newDevice
        captureSession.commitConfiguration()
    }

    @objc func zoomIn() {
        if let zoomFactor = currentDevice?.videoZoomFactor {
            if zoomFactor < 5.0 {
                let newZoomFactor = min(zoomFactor + 1.0, 5.0)
                do {
                    try currentDevice?.lockForConfiguration()
                    currentDevice?.ramp(toVideoZoomFactor: newZoomFactor, withRate: 1.0)
                    currentDevice?.unlockForConfiguration()
                } catch {
                    print(error)
                }
            }
        }
    }

    @objc func zoomOut() {
        if let zoomFactor = currentDevice?.videoZoomFactor {
            if zoomFactor > 1.0 {
                let newZoomFactor = max(zoomFactor - 1.0, 1.0)
                do {
                    try currentDevice?.lockForConfiguration()
                    currentDevice?.ramp(toVideoZoomFactor: newZoomFactor, withRate: 1.0)
                    currentDevice?.unlockForConfiguration()
                } catch {
                    print(error)
                }
            }
        }
    }

    @IBAction func cameraButton_TouchUpInside(_ sender: Any) {
        let settings = AVCapturePhotoSettings()
        self.photoOutput?.capturePhoto(with: settings, delegate: self)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "Preview_Segue" {
            let previewViewController = segue.destination as! PreviewViewController
            previewViewController.image = self.image
        }
    }
}

extension ViewController: AVCapturePhotoCaptureDelegate {
    func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
        if let imageData = photo.fileDataRepresentation() {
            self.image = UIImage(data: imageData)
            performSegue(withIdentifier: "Preview_Segue", sender: nil)
        }
    }
}

我只想将更改/切换相机的功能从后置摄像头更改为前置摄像头，反之亦然，当我们向上滑动视图（使用手势识别器）时，代码切换摄像头发生了，但我想改变它使用按钮切换动作，因此在用户按下按钮后，它将从后置摄像头变为前置摄像头，反之亦然

我认为我只是将@objc func switchCamera（）中的代码移动到@IBaction，但在我按下按钮后，从前向后切换相机自动捕获图像我无法获得图像

说实话，我并没有真正掌握代码，所以我需要你的帮助才能编辑切换操作，我该怎么做？