自定义iPhone相机控件(不使用UIImagePickerController)

import AVFoundation

class CustomCameraViewController: UIViewController {
    var captureSession: AVCaptureSession!
    var previewLayer: AVCaptureVideoPreviewLayer!
    var photoOutput: AVCapturePhotoOutput!

    override func viewDidLoad() {
        super.viewDidLoad()

        // 创建AVCaptureSession实例
        captureSession = AVCaptureSession()

        // 设置相机的输入和输出
        let captureDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back)
        let input = try! AVCaptureDeviceInput(device: captureDevice!)
        captureSession.addInput(input)

        // 创建预览图层
        previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        previewLayer.frame = view.bounds
        view.layer.addSublayer(previewLayer)

        // 实现聚焦、曝光和白平衡控件
        let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(focusAndExposeTap))
        view.addGestureRecognizer(tapGestureRecognizer)

        // 实现拍照和录像功能
        photoOutput = AVCapturePhotoOutput()
        captureSession.addOutput(photoOutput)
    }

    @objc func focusAndExposeTap(sender: UITapGestureRecognizer) {
        let tapPoint = sender.location(in: view)
        let focusPoint = previewLayer.captureDevicePointConverted(fromLayerPoint: tapPoint)
        let exposurePoint = previewLayer.captureDevicePointConverted(fromLayerPoint: tapPoint)

        let device = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back)
        do {
            try device?.lockForConfiguration()
            device?.focusPointOfInterest = focusPoint
            device?.exposurePointOfInterest = exposurePoint
            device?.exposureMode = .continuousAutoExposure
            device?.focusMode = .continuousAutoFocus
            device?.unlockForConfiguration()
        } catch {
            print("Error focusing and exposing: \(error)")
        }
    }
}