ios - 加载二维码到另一个 View Controller (Xcode)

Question

我目前正在做一个测验应用程序，用户必须扫描二维码才能做第一个问题，然后扫描另一个二维码到第二个问题。截至目前，我的二维码扫描仪只能将二维码扫描到网址。我已经为我的问题完成了布局和按钮，我只需要 qr 代码链接到我的 qn Controller 。提前谢谢你。

这是我的 QRScannerController.swift

import UIKit
import AVFoundation

class QRScannerController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    @IBOutlet var messageLabel:UILabel!
    @IBOutlet var topbar: UIView!

    var captureSession:AVCaptureSession?
    var videoPreviewLayer:AVCaptureVideoPreviewLayer?
    var qrCodeFrameView:UIView?

    let supportedCodeTypes = [AVMetadataObjectTypeUPCECode,
                        AVMetadataObjectTypeCode39Code,
                        AVMetadataObjectTypeCode39Mod43Code,
                        AVMetadataObjectTypeCode93Code,
                        AVMetadataObjectTypeCode128Code,
                        AVMetadataObjectTypeEAN8Code,
                        AVMetadataObjectTypeEAN13Code,
                        AVMetadataObjectTypeAztecCode,
                        AVMetadataObjectTypePDF417Code,
                        AVMetadataObjectTypeQRCode]

    override func viewDidLoad() {
        super.viewDidLoad()

        // Get an instance of the AVCaptureDevice class to initialize a device object and provide the video as the media type parameter.
        let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)

        do {
            // Get an instance of the AVCaptureDeviceInput class using the previous device object.
            let input = try AVCaptureDeviceInput(device: captureDevice)

            // Initialize the captureSession object.
            captureSession = AVCaptureSession()

            // Set the input device on the capture session.
            captureSession?.addInput(input)

            // Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
            let captureMetadataOutput = AVCaptureMetadataOutput()
            captureSession?.addOutput(captureMetadataOutput)

            // Set delegate and use the default dispatch queue to execute the call back
            captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
            captureMetadataOutput.metadataObjectTypes = supportedCodeTypes

            // Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
            videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
            videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
            videoPreviewLayer?.frame = view.layer.bounds
            view.layer.addSublayer(videoPreviewLayer!)

            // Start video capture.
            captureSession?.startRunning()

            // Move the message label and top bar to the front
            view.bringSubview(toFront: messageLabel)
            view.bringSubview(toFront: topbar)

            // Initialize QR Code Frame to highlight the QR code
            qrCodeFrameView = UIView()

            if let qrCodeFrameView = qrCodeFrameView {
                qrCodeFrameView.layer.borderColor = UIColor.green.cgColor
                qrCodeFrameView.layer.borderWidth = 2
                view.addSubview(qrCodeFrameView)
                view.bringSubview(toFront: qrCodeFrameView)
            }

        } catch {
            // If any error occurs, simply print it out and don't continue any more.
            print(error)
            return
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    // MARK: - AVCaptureMetadataOutputObjectsDelegate Methods

    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {

        // Check if the metadataObjects array is not nil and it contains at least one object.
        if metadataObjects == nil || metadataObjects.count == 0 {
            qrCodeFrameView?.frame = CGRect.zero
            messageLabel.text = "No QR/barcode is detected"
            return
        }

        // Get the metadata object.
        let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject

        if supportedCodeTypes.contains(metadataObj.type) {
            // If the found metadata is equal to the QR code metadata then update the status label's text and set the bounds
            let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
            qrCodeFrameView?.frame = barCodeObject!.bounds

            if metadataObj.stringValue != nil {
                let url = URL(string: metadataObj.stringValue)!
                if #available(iOS 10.0, *) {
                    UIApplication.shared.open(url, options: [:], completionHandler: nil)
                } else {
                    UIApplication.shared.openURL(url)
                }
            }
        }
    }

}

这是我的问题 Controller

import UIKit    
class Quiz1Controller: UIViewController {    
    override func viewDidLoad() {
        super.viewDidLoad()    
        // Do any additional setup after loading the view.
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

Answer 1

我建议您创建一个帮助程序文件，以将 QRCode 扫描与 UIViewController 分开。这会清理您的代码并实现可重用性。

回答你的问题。您可以更改方法 func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) { 来处理扫描的 QRCode 的输出。

我实际上实现了一个委托(delegate)来从 QRCodeHelper 返回值，但您也可以在没有文件的情况下调用函数。

为此，创建一个新函数 func qrScanDidScanCode(_ code:String) 并像这样在 captureOutput 中调用它。

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
    var QRCode: String?
    for metadata in metadataObjects as! [AVMetadataObject] {
        if metadata.type == AVMetadataObjectTypeQRCode {
            QRCode = (metadata as! AVMetadataMachineReadableCodeObject).stringValue
        }
    }

    if let qr = QRCode {
        qrScanDidScanCode(qr)
    }
}

qr 变量将 QRCodes 值保存为字符串，您现在可以在任何您喜欢的地方使用它。

如果你想在你的下一个 viewController 中使用 QRCodes 的字符串值。使用 segues 方法执行和准备。

在当前的 UIViewController 中创建一个新属性:var selectedQRCode:String? 在 qrScanDidScanCode() 中设置它 在设置 selectedQRCode 后调用 performSegue。

在 prepareSegue 中，做这样的事情:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let destination = segue.destination as? SecondViewController {
        destination.qrCode = selectedQRCode
    }
}