gistfile1.txt

//When the user taps a button we call this function

func presentScanner() {
    let t = viewModel.transaction
    guard let recognizerRunnerController = RecognizerProvider().controller(transaction: t) else { return }

    self.navigationController?.pushViewController(recognizerRunnerController, animated: true)
}

// The RecognizerProvider looks like this
//This class configures the custome overlay scanner to be presented:

class RecognizerProvider {

    var pdf417Recognizer : MBPdf417Recognizer?
    var barcodeRecognizer : MBBarcodeRecognizer?

    func controller(transaction: OngoingTransaction) -> UIViewController? {
        MBMicroblinkSDK.sharedInstance().setLicenseKey("license")

        /** Create barcode recognizer */
        self.barcodeRecognizer = MBBarcodeRecognizer()
        self.barcodeRecognizer?.scanQrCode = true

        self.pdf417Recognizer = MBPdf417Recognizer()
        self.pdf417Recognizer?.scanUncertain = true

        /** Crate recognizer collection */
        let recognizerList = [self.pdf417Recognizer!, self.barcodeRecognizer!]
        let recognizerCollection = MBRecognizerCollection(recognizers: recognizerList)

        /** Create your overlay view controller */
        let customOverlayViewController = OverlayViewController.instantiate(transaction: transaction)

        /** This has to be called for custom controller */
        customOverlayViewController.reconfigureRecognizers(recognizerCollection)

        /** Create recognizer view controller with wanted overlay view controller */
        return MBViewControllerFactory.recognizerRunnerViewController(
            withOverlayViewController: customOverlayViewController)
    }
}

Now this is tha delegate function in the overlay controller

extension OverlayViewController: MBScanningRecognizerRunnerViewControllerDelegate {

    func recognizerRunnerViewController(_ recognizerRunnerViewController: UIViewController & MBRecognizerRunnerViewController,
                                        didFinishScanningWith state: MBRecognizerResultState) {

        if state == MBRecognizerResultState.valid {
            DispatchQueue.main.sync { [weak self] in
                guard let s = self else { return }
                s.recognizerRunnerViewController?.pauseScanning()
                s.recognizerRunnerViewController?.pauseCamera()
                for recognizer in s.recognizerCollection.recognizerList where
                    recognizer.baseResult?.resultState == MBRecognizerResultState.valid && recognizer is MBPdf417Recognizer {
                        let pdf417Recognizer = recognizer as? MBPdf417Recognizer
                        if let rawData = pdf417Recognizer?.result.stringData {
                            <talk to our server here>
                        }
                }
            }
        }
    }
}