QRコードをスキャンしよう

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "conform"{
        let vc = segue.destination as! FriendConformView
        let data = sender as! UserData
        vc.userID = data.id
        vc.name = data.name
    }
    if segue.identifier == "qr"{
        let vc = segue.destination as! QRScanner
        vc.qrScaned = {
            id in
            self.conform(id: id)
        }
    }
}

import AVFoundation
import AudioToolbox
import UIKit

class QRScanner:UIViewController,AVCaptureMetadataOutputObjectsDelegate {
    
    @IBAction func onBack(_ sender: Any) {
        dismiss(animated: true, completion: nil)
    }
    @IBOutlet weak var backButton: UIButton!
    
    var qrScaned = {(result:String)in}
    
    let captureSession = AVCaptureSession()
    var videoPreviewLayer:AVCaptureVideoPreviewLayer?
    var qrCodeFrameView:UIView?
    
    let deviceDiscoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position:.back)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        guard let captureDevice = deviceDiscoverySession.devices.first else {
            print("Failed to get the camera device")
            return
        }
        do {
            let input = try AVCaptureDeviceInput(device: captureDevice)
            captureSession.addInput(input)
            let captureMetadataOutput = AVCaptureMetadataOutput()
            captureSession.addOutput(captureMetadataOutput)
            captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
            captureMetadataOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]
            videoPreviewLayer = AVCaptureVideoPreviewLayer.init(session: captureSession)
            videoPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
            videoPreviewLayer?.frame = view.layer.bounds
            view.layer.addSublayer(videoPreviewLayer!)
            self.captureSession.startRunning()
            qrCodeFrameView = UIView()
            view.bringSubviewToFront(backButton)
            if let qrCodeFrameView = qrCodeFrameView {
                qrCodeFrameView.layer.borderColor = UIColor.green.cgColor
                qrCodeFrameView.layer.borderWidth = 2
                view.addSubview(qrCodeFrameView)
                view.bringSubviewToFront(qrCodeFrameView)
            }
        } catch {
            print(error)
            return
        }
    }
    
    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        if metadataObjects.count == 0 {
            qrCodeFrameView?.frame = CGRect.zero
            return
        }
        let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
        if metadataObj.type == AVMetadataObject.ObjectType.qr {
            let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
            qrCodeFrameView?.frame = barCodeObject!.bounds
            if metadataObj.stringValue != nil {
                captureSession.stopRunning()
                AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
                DispatchQueue.main.asyncAfter(deadline: .now() + 1){
                    self.dismiss(animated: true, completion: nil)
                    self.qrScaned(metadataObj.stringValue!)
                }
            }
        }
    }
    
}