iOS Swift Barcode Reading

http://shrikar.com/implementing-barcode-scanning-in-ios8-with-swift/

http://www.appcoda.com/qr-code-reader-swift/

https://www.hackingwithswift.com/example-code/media/how-to-scan-a-barcode


http://stackoverflow.com/questions/31170750/ios-swift-barcode-reading

import UIKit
import AVFoundation


class BarCodeViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    let session         : AVCaptureSession = AVCaptureSession()
    var previewLayer    : AVCaptureVideoPreviewLayer!
    @IBOutlet weak var highlightView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Allow the view to resize freely
//        self.highlightView.autoresizingMask =   UIViewAutoresizing.FlexibleTopMargin |
//            UIViewAutoresizing.FlexibleBottomMargin |
//            UIViewAutoresizing.FlexibleLeftMargin |
//            UIViewAutoresizing.FlexibleRightMargin
//        
        // Select the color you want for the completed scan reticle
        self.highlightView.layer.borderColor = UIColor.greenColor().CGColor
        self.highlightView.layer.borderWidth = 3

        // Add it to our controller's view as a subview.
        self.view.addSubview(self.highlightView)


        // For the sake of discussion this is the camera
        let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

        // Create a nilable NSError to hand off to the next method.
        // Make sure to use the "var" keyword and not "let"
        var error : NSError? = nil
        var input: AVCaptureDeviceInput = AVCaptureDeviceInput()
        do {
            input = try  AVCaptureDeviceInput(device: device) as AVCaptureDeviceInput
        } catch let myJSONError {
            print(myJSONError)
        }

        // If our input is not nil then add it to the session, otherwise we're kind of done!
        if input !=  AVCaptureDeviceInput() {
            session.addInput(input)
        }
        else {
            // This is fine for a demo, do something real with this in your app. :)
            print(error)
        }

        let output = AVCaptureMetadataOutput()
        output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
        session.addOutput(output)
        output.metadataObjectTypes = output.availableMetadataObjectTypes


        previewLayer = AVCaptureVideoPreviewLayer(session: session)
        previewLayer.frame = self.view.bounds
        previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
        self.view.layer.addSublayer(previewLayer)

        // Start the scanner. You'll have to end it yourself later.
        session.startRunning()

    }

    // This is called when we find a known barcode type with the camera.
    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {

        var highlightViewRect = CGRectZero

        var barCodeObject : AVMetadataObject!

        var detectionString : String!

        let barCodeTypes = [AVMetadataObjectTypeUPCECode,
            AVMetadataObjectTypeCode39Code,
            AVMetadataObjectTypeCode39Mod43Code,
            AVMetadataObjectTypeEAN13Code,
            AVMetadataObjectTypeEAN8Code,
            AVMetadataObjectTypeCode93Code,
            AVMetadataObjectTypeCode128Code,
            AVMetadataObjectTypePDF417Code,
            AVMetadataObjectTypeQRCode,
            AVMetadataObjectTypeAztecCode
        ]


        // The scanner is capable of capturing multiple 2-dimensional barcodes in one scan.
        for metadata in metadataObjects {

            for barcodeType in barCodeTypes {

                if metadata.type == barcodeType {
                    barCodeObject = self.previewLayer.transformedMetadataObjectForMetadataObject(metadata as! AVMetadataMachineReadableCodeObject)

                    highlightViewRect = barCodeObject.bounds

                    detectionString = (metadata as! AVMetadataMachineReadableCodeObject).stringValue

                    self.session.stopRunning()

                    self.alert(detectionString)
                    break
                }

            }
        }

        print(detectionString)
        self.highlightView.frame = highlightViewRect
        self.view.bringSubviewToFront(self.highlightView)

    }



    func alert(Code: String){
        let actionSheet:UIAlertController = UIAlertController(title: "Barcode", message: "\(Code)", preferredStyle: UIAlertControllerStyle.Alert)

        // for alert add .Alert instead of .Action Sheet


        // start copy

        let firstAlertAction:UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:


            {
                (alertAction:UIAlertAction!) in


                // action when pressed

                self.session.startRunning()




        })

        actionSheet.addAction(firstAlertAction)

        // end copy






        self.presentViewController(actionSheet, animated: true, completion: nil)

    }



}