AVFoundation camera focus stops working after switching from barcode scanner - ios

Question

I have an application that uses RSBarcodes_Swift to scan for barcodes.
When the scan is successful i need to segue to camera view controller to take pictures. The problem i have is that after the barcode scanner, AVFoundation touch to focus stops working. What i mean by this is that whenever i touch to focus, camera just briefly tries to focus and than resets to default lens position. When i don't use barcode scanner and go directly to camera, everything works fine. I have also used a couple of other barcode scanners, but the result is the same. Is there any way that i somehow reset the camera usage, or dispose of barcode scanner when i'm done with it?
This is the code i use to present the camera and have touch to focus capability:
import Foundation
import AVFoundation
public class CameraViewController : UIViewController {
var backCamera: AVCaptureDevice?
var captureSession: AVCaptureSession?
var stillImageOutput: AVCaptureStillImageOutput?
var videoPreviewLayer: AVCaptureVideoPreviewLayer?
var previewView: UIView?
public override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
previewView = UIView()
previewView!.frame = UIScreen.mainScreen().bounds
let shortTap = UITapGestureRecognizer(target: self, action: #selector(shortTapRecognize))
shortTap.numberOfTapsRequired = 1
shortTap.numberOfTouchesRequired = 1
previewView!.addGestureRecognizer(shortTap)
self.view.addSubview(previewView!)
captureSession = AVCaptureSession()
captureSession!.sessionPreset = AVCaptureSessionPresetPhoto
backCamera = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
var error: NSError?
var input: AVCaptureDeviceInput!
do {
input = try AVCaptureDeviceInput(device: backCamera!)
} catch let error1 as NSError{
error = error1
input = nil
print(error!.localizedDescription)
}
if error == nil && captureSession!.canAddInput(input){
captureSession!.addInput(input)
stillImageOutput = AVCaptureStillImageOutput()
stillImageOutput?.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]
if captureSession!.canAddOutput(stillImageOutput){
captureSession!.addOutput(stillImageOutput)
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
videoPreviewLayer!.frame = previewView!.bounds
videoPreviewLayer!.videoGravity = AVLayerVideoGravityResizeAspect
videoPreviewLayer!.connection?.videoOrientation = AVCaptureVideoOrientation.LandscapeRight
previewView!.layer.addSublayer(videoPreviewLayer!)
captureSession!.startRunning()
}
}
}
public override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
}
public override func viewDidLoad() {
super.viewDidLoad()
}
public override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func shortTapRecognize(tap: UITapGestureRecognizer){
if tap.state == UIGestureRecognizerState.Ended {
let pointInPreview = tap.locationInView(tap.view)
let pointInCamera = videoPreviewLayer!.captureDevicePointOfInterestForPoint(pointInPreview)
if backCamera!.focusPointOfInterestSupported{
do {
try backCamera!.lockForConfiguration()
} catch let error as NSError{
print(error.localizedDescription)
}
backCamera!.focusPointOfInterest = pointInCamera
backCamera!.focusMode = .AutoFocus
backCamera!.unlockForConfiguration()
}
}
}
}