Capture a QR with iPhone camera.

QRCaptureViewController.swift

//
//  QRCaptureViewController.swift
//  ScanQR
//
//  Created by Daniel Vela on 06/08/15.
//  Copyright (c) 2015 veladan. All rights reserved.
//

import UIKit
import AVFoundation

class QRCaptureViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    var captureSession: AVCaptureSession?
    var videoPreviewLayer: AVCaptureVideoPreviewLayer?
    
    // View port to display the video capture preview
    @IBOutlet weak var viewPreview: UIView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }
    
    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        
        self.startReading()
    }

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


    func startReading() -> Bool {
        var error: NSError?
    
        var captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
        
        var input: AVCaptureInput = AVCaptureDeviceInput.deviceInputWithDevice(captureDevice, error: &error) as! AVCaptureInput
        
        if let error = error {
            NSLog("%@", error.localizedDescription)
            return false
        }
        
        
        
        captureSession = AVCaptureSession()
        captureSession!.addInput(input);
        
        var captureMetadataOutput = AVCaptureMetadataOutput()
        captureSession!.addOutput(captureMetadataOutput)
        
        var dispatchQueue: dispatch_queue_t;
        dispatchQueue = dispatch_queue_create("myqueue",  nil)
        captureMetadataOutput.setMetadataObjectsDelegate(self, queue: dispatchQueue)
        captureMetadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
        
        videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
        videoPreviewLayer?.frame = viewPreview!.layer.bounds

        viewPreview?.layer.addSublayer(videoPreviewLayer)
        
        captureSession?.startRunning()
        
        return true;
    }
    
    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
        if let metadataObjects = metadataObjects {
            if metadataObjects.count > 0 {
                var metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
                if metadataObj.type == AVMetadataObjectTypeQRCode {
                    NSLog("Cpature: %@", metadataObj.stringValue)
                }
            }
        }
    }
}