ScanViewController.swift

// Created by Carsten Hagemann @ Kaufland Informationssysteme
// With code from the SDK docs: https://help.sap.com/doc/978e4f6c968c4cc5a30f9d324aa4b1d7/Latest/en-US/Documents/Frameworks/SAPFiori/Classes/FUIBarcodeScanViewController.html

import UIKit
import SAPFiori

class ScanViewController: UIViewController, FUIBarcodeScanViewControllerDelegate {

    private var scanViewController: FUIBarcodeScanViewController?

    @IBOutlet weak var startScanView: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        #if targetEnvironment(simulator)
            print("\nScanning is not possible in the Simulator!\n")
        #endif

        scanViewController = FUIBarcodeScanViewController.createInstanceFromStoryboard()
        guard let safeScanViewController = scanViewController, safeScanViewController.barcodeScanner != nil else {
            return
        }

        safeScanViewController.barcodeScanner.scanMode = .qr
        safeScanViewController.barcodeScanner.indicatorBorderColor = UIColor.green.cgColor
        safeScanViewController.barcodeScanner.indicatorBorderWidth = 5
        safeScanViewController.barcodeScanner.promptMessage = "Scan A QR Code"
        safeScanViewController.barcodeScanner.scanResultTransformer = { scanString in
            // Modify the scanned String here
            return scanString
        }
        safeScanViewController.delegate = self

        self.startScanView.addTarget(nil, action: #selector(showScanView), for: .touchUpInside)
    }

    @objc func showScanView() {
        guard let safeScanViewController = scanViewController else {
            return
        }
        let navController = UINavigationController(rootViewController: safeScanViewController)
        self.navigationController?.present(navController, animated: true, completion: nil)
    }

    func barcodeScanViewController(_ barcodeScanViewController: FUIBarcodeScanViewController, didReceiveScanResult scanResult: FUIBarcodeScanResult?) {
        print("Scanned '\(scanResult?.scanResultString ?? "")'")
        let scanSuccessful = (scanResult?.scanResultString.count ?? 0) > 3 // Move this out as a method
        if scanSuccessful {
            barcodeScanViewController.dismiss(animated: true, completion: nil)
        } else {
            print(scanResult?.scanResultString as Any)
            guard let safeScanViewController = scanViewController else {
                return
            }
            safeScanViewController.barcodeScanner.promptMessage = "QR Code was not valid. Please scan again."
        }
    }

}