ios - 通过 xcode 11 swift 5 ios 访问 iphone 相机

Question

我正在尝试访问我的 iPhone相机通过下面的代码。 但是当我运行应用程序时，我的 square 只会出现白屏。图像意味着相机没有出现。

import UIKit
import AVFoundation

class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    var camera = AVCaptureVideoPreviewLayer()
    @IBOutlet weak var square: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let begin = AVCaptureSession()
      guard  let captureCamera = AVCaptureDevice.default(.builtInDualCamera,
        for: AVMediaType.video,
        position: .back) else { return }

        do {
            let start = try AVCaptureDeviceInput(device: captureCamera)
            begin.addInput(start)  
        }
        catch{
            print("error" )
        }

它不会在任何地方打印出“错误”

Answer 1

据我所知，您必须初始化一个预览层并将其添加到您的 View 中。

do {
    let start = try AVCaptureDeviceInput(device: captureCamera)
    begin.addInput(start) 
    let videoPreviewLayer = AVCaptureVideoPreviewLayer(session: begin)
    view.layer.addSublayer(videoPreviewLayer)
} catch{
    print("error" )
}