Simple Barcode Scanning with Swift 2.1

ViewController.swift

import UIKit
import AVFoundation


class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    let session         : AVCaptureSession = AVCaptureSession()
    var previewLayer    : AVCaptureVideoPreviewLayer!
    var highlightView   : UIView = 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)
        
        do {
            let input : AVCaptureDeviceInput? = try AVCaptureDeviceInput(device: device)
            
            // If our input is not nil then add it to the session, otherwise we're kind of done!
            session.addInput(input)
            
            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()
        } catch let error as NSError {
            print(error)
        }
    
    }
    
    // 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()
                    break
                }
                
            }
        }
        
        print(detectionString)
        self.highlightView.frame = highlightViewRect
        self.view.bringSubviewToFront(self.highlightView)
        
    }


}