Swift二维码扫描实现(自定义UI)

前不久有网友跟我说，demo有bug不能运行，所以抽空改了一下，主要原因是swift版本问题，当初我写这个demo的时候是Swift3.0 贝塔版，所以有些语法上的更新。

在过去的WWDC2016中，Apple Inc推出了新版Swift--Swift3.0；对于Swift3.0的语法什么的，在此就不聊了，毕竟人家还是个小白。

书归正传，iOS7.0以前要使用二维码扫描功能，需要借助两大开源的组件ZBar和ZXing来实现，自iOS7.0之后可以使用自带的AVFoundation框架实现二维码扫描，而且效率更高。

因此实现二维码扫描首先需要导入AVFoundation框架

• 1 导入AVFoundation框架

import AVFoundation

• 2 创建视图预览显示并设置想实现的UI效果

//屏幕扫描区域视图
 //屏幕扫描区域视图
    let barcodeView = UIView(frame: CGRect(x: UIScreen.main.bounds.size.width * 0.2, y: UIScreen.main.bounds.size.height * 0.35, width: UIScreen.main.bounds.size.width * 0.6, height: UIScreen.main.bounds.size.width * 0.6))
    //扫描线
    let scanLine = UIImageView()
    
    var scanning : String!
    var timer = Timer()
 
  override init(frame: CGRect) {
    super.init(frame: frame)
  barcodeView.layer.borderWidth = 1.0
        barcodeView.layer.borderColor = UIColor.white.cgColor
        self.addSubview(barcodeView)
        
        //设置扫描线
        scanLine.frame = CGRect(x: 0, y: 0, width: barcodeView.frame.size.width, height: 5)
        scanLine.image = UIImage(named: "QRCodeScanLine")
        
        //添加扫描线图层
        barcodeView.addSubview(scanLine)
        
        self.createBackGroundView()
        
        self.addObserver(self, forKeyPath: "scanning", options: .new, context: nil)
        
        timer = Timer.scheduledTimer(timeInterval: 2, target: self, selector: #selector(moveScannerLayer(_:)), userInfo: nil, repeats: true)
  }

• 3 实现背景灰色半透明，分四个View,设置所需要实现的样式；同样的也可以采用重写drawRect方法来实现。

func createBackGroundView() {
   let topView = UIView(frame: CGRect(x: 0, y: 0,  width: UIScreen.main.bounds.size.width, height: UIScreen.main.bounds.size.height * 0.35))
        let bottomView = UIView(frame: CGRect(x: 0, y: UIScreen.main.bounds.size.width * 0.6 + UIScreen.main.bounds.size.height * 0.35, width: UIScreen.main.bounds.size.width, height: UIScreen.main.bounds.size.height * 0.65 - UIScreen.main.bounds.size.width * 0.6))
        
        let leftView = UIView(frame: CGRect(x: 0, y: UIScreen.main.bounds.size.height * 0.35, width: UIScreen.main.bounds.size.width * 0.2, height: UIScreen.main.bounds.size.width * 0.6))
        let rightView = UIView(frame: CGRect(x: UIScreen.main.bounds.size.width * 0.8, y: UIScreen.main.bounds.size.height * 0.35, width: UIScreen.main.bounds.size.width * 0.2, height: UIScreen.main.bounds.size.width * 0.6))
        
        topView.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.4)
        bottomView.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.4)
        leftView.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.4)
        rightView.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.4)
        
        let label = UILabel(frame: CGRect(x: 0, y: 10, width: UIScreen.main.bounds.size.width, height: 21))
        label.textAlignment = .center
        label.font = UIFont.systemFont(ofSize: 14)
        label.textColor = UIColor.white
        label.text = "将二维码/条形码放入扫描框内，即自动扫描"
        
        bottomView.addSubview(label)
        
        
        self.addSubview(topView)
        self.addSubview(bottomView)
        self.addSubview(leftView)
        self.addSubview(rightView)
  }

• 4 在初始化视图的时候添加观察者，用于实现暂停扫描时，扫描线停止滚动

self.addObserver(self, forKeyPath: "scanning", options: .new, context: nil)

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        
        if scanning == "start" {
            timer.fire()
        }else{
            timer.invalidate()
        }
    }

• 5 扫描线滚动动画

//让扫描线滚动
  func moveScannerLayer(_ timer : Timer) {
    scanLine.frame = CGRect(x: 0, y: 0, width: self.barcodeView.frame.size.width, height: 12)
    UIView.animate(withDuration: 2) {
      self.scanLine.frame = CGRect(x: self.scanLine.frame.origin.x, y: self.scanLine.frame.origin.y + self.barcodeView.frame.size.height - 10, width: self.scanLine.frame.size.width, height: self.scanLine.frame.size.height) 
    }
  }

• 6 声明背景视图

//相机显示视图
    let cameraView = ScannerBackgroundView(frame: UIScreen.main.bounds)

• 7 初始化捕捉设备、创建捕捉会话、输入媒体类型、设置代理等

    let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
   
    let input :AVCaptureDeviceInput
   
    let output = AVCaptureMetadataOutput()
   
    //捕捉异常,并处理异常
    do{
      input = try AVCaptureDeviceInput(device: captureDevice)
      captureSession.addInput(input)
      captureSession.addOutput(output)
    }catch {
      print("异常")
    }
    let dispatchQueue = DispatchQueue(label: "queue", attributes: [])
    output.setMetadataObjectsDelegate(self, queue: dispatchQueue)
    output.metadataObjectTypes = NSArray(array: [AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code,AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code]) as [AnyObject]
    let videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
   
    videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
   
    videoPreviewLayer?.frame = cameraView.bounds
   
    cameraView.layer.insertSublayer(videoPreviewLayer!, at: 0)

    output.rectOfInterest = CGRect(x: 0.2, y: 0.2, width: 0.6, height: 0.6)

• 8 扫描结果处理(根据不同扫描结果，执行不同的操作)

 if metadataObjects != nil && metadataObjects.count > 0 {
            let metaData : AVMetadataMachineReadableCodeObject = metadataObjects.first as! AVMetadataMachineReadableCodeObject
            
            print(metaData.stringValue)
            
            DispatchQueue.main.async(execute: {
                let result = WebViewController()
                result.url = metaData.stringValue
                
                self.navigationController?.pushViewController(result, animated: true)
            })
            captureSession.stopRunning()
        }

• 9 从相册中获取二维码图片进行识别，在此需要判断相册中获取的图片是否具有二维码信息

let image = info[UIImagePickerControllerOriginalImage]
   
    let imageData = UIImagePNGRepresentation(image as! UIImage)
   
    let ciImage = CIImage(data: imageData!)
   
    let detector = CIDetector(ofType: CIDetectorTypeQRCode, context: nil, options: [CIDetectorAccuracy: CIDetectorAccuracyLow])
   
    let array = detector?.features(in: ciImage!)
   
    let result : CIQRCodeFeature = array!.first as! CIQRCodeFeature
   
   
    let resultView = WebViewController()
    resultView.url = result.messageString
   
    self.navigationController?.pushViewController(resultView, animated: true)
    picker.dismiss(animated: true, completion: nil)

欧了，所有工作都已完成；由于本人是个菜鸟，思路仅供参考，如果有更好的思路，欢迎交流。
附上：
demo地址：demo下载