Use of unresolved identifier "scanQRCode" - swift

Question

I created a project with tab bars in Obj-C XCode and then I just want import a barcode scanner app to my project. I got finally a error when i told myself "Yes it will work". Can you help to figure it out ?
import UIKit
import AVFoundation
class Barcode: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
#IBOutlet var videoPreview: UIView!
var stringURL = String()
enum error: Error {
case noCameraAvailable
case videoInputInitFail
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
do{
try scanQRCode() /* I take error message right here "Use unresolved identifier"*/
}
catch{
print("Tarama Gerçekleşemedi!")
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection){
if metadataObjects.count > 0 {
let machineReadableCode = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
if machineReadableCode.type == AVMetadataObjectTypeQRCode {
stringURL = machineReadableCode.stringValue!
performSegue(withIdentifier: "openLink", sender: self)
}
}
}
func scanQRCode()
throws {
let avCaptureSession = AVCaptureSession()
guard let avCaptureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo) else{
print("Kamera Bulunamadı!")
throw error.noCameraAvailable
}
guard let avCaptureInput = try? AVCaptureDeviceInput(device: avCaptureDevice)
else{
print("Kameraya Erişilemedi!")
throw error.videoInputInitFail
}
let avCaptureMetadataOutput = AVCaptureMetadataOutput()
avCaptureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
avCaptureSession.addInput(avCaptureInput)
avCaptureSession.addOutput(avCaptureMetadataOutput)
avCaptureMetadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
let avCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: avCaptureSession)
avCaptureVideoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
avCaptureVideoPreviewLayer?.frame = videoPreview.bounds
self.videoPreview.layer.addSublayer(avCaptureVideoPreviewLayer!)
avCaptureSession.startRunning()
}
func prepare(for segue: UIStoryboardSegue, sender: Any?){
if segue.identifier == "openLink"{
let destination = segue.destination as! WebViewController
destination.url = URL(string: stringURL)
}
}
}
}
My main ViewController classes are Obj-C but i created barcode.swift for barcode-tab. This error about it or not ?

Answer 1

You have created that function within another function, didReceiveMemoryWarning. which you shouldn't.
Move scanQRCode and all other functions you have declared inside didReceiveMemoryWarning outside of it.
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning().
}
func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection){
//...
}
func scanQRCode() throws {
//...
}
func prepare(for segue: UIStoryboardSegue, sender: Any?){
//...
}