iOS QR

QR.swift

import UIKit
import AVFoundation

class QRScanViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    
    var captureSession: AVCaptureSession?
    var videoPreviewLayer: AVCaptureVideoPreviewLayer?
    var qrCodeFrameView: UIView?
    
    // Added to support different barcodes
    let supportedBarCodes = [AVMetadataObjectTypeQRCode]

    override func viewDidLoad() {
        super.viewDidLoad()

        // Get an instance of the AVCaptureDevice class to initialize a device object and provide the video
        // as the media type parameter.
        let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
        
        do {
            // Get an instance of the AVCaptureDeviceInput class using the previous device object.
            let input = try AVCaptureDeviceInput(device: captureDevice)
            
            // Initialize the captureSession object.
            captureSession = AVCaptureSession()
            // Set the input device on the capture session.
            captureSession?.addInput(input)
            
            // Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
            let captureMetadataOutput = AVCaptureMetadataOutput()
            captureSession?.addOutput(captureMetadataOutput)
            
            // Set delegate and use the default dispatch queue to execute the call back
            captureMetadataOutput.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
            
            // Detect all the supported bar code
            captureMetadataOutput.metadataObjectTypes = supportedBarCodes
            
            // Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
            videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
            videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
            videoPreviewLayer?.frame = view.layer.bounds
            view.layer.addSublayer(videoPreviewLayer!)
            
            // Start video capture
            captureSession?.startRunning()
            
            // Move the message label to the top view
            // view.bringSubviewToFront(messageLabel)
            
            // Initialize QR Code Frame to highlight the QR code
            qrCodeFrameView = UIView()
            
            if let qrCodeFrameView = qrCodeFrameView {
                qrCodeFrameView.layer.borderColor = UIColor.greenColor().CGColor
                qrCodeFrameView.layer.borderWidth = 2
                view.addSubview(qrCodeFrameView)
                view.bringSubviewToFront(qrCodeFrameView)
            }
            
        } catch {
            // If any error occurs, simply print it out and don't continue any more.
            print(error)
            return
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
 
        // Check if the metadataObjects array is not nil and it contains at least one object.
        if metadataObjects == nil || metadataObjects.count == 0 {
            qrCodeFrameView?.frame = CGRectZero
            // messageLabel.text = "No barcode/QR code is detected"
            return
        }
        
        // Get the metadata object.
        let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
        
        // Here we use filter method to check if the type of metadataObj is supported
        // Instead of hardcoding the AVMetadataObjectTypeQRCode, we check if the type
        // can be found in the array of supported bar codes.
        if supportedBarCodes.contains(metadataObj.type) {
            // If the found metadata is equal to the QR code metadata then update the status label's text and set the bounds
            let barCodeObject = videoPreviewLayer?.transformedMetadataObjectForMetadataObject(metadataObj)
            qrCodeFrameView?.frame = barCodeObject!.bounds
            
            if metadataObj.stringValue != nil {
                // messageLabel.text = metadataObj.stringValue
                print(metadataObj.stringValue)
            }
        }
    }

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}