swift

Swift 二维码QRCode

Swift 二维码QRCode
1，直接读取图片中的二维码

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let qrcodeImg =  UIImage(named: "codeBg.png")
      let ciImage:CIImage=CIImage(image:qrcodeImg!)!
      let context = CIContext(options: nil)
      let detector:CIDetector=CIDetector(ofType: CIDetectorTypeQRCode,
          context: context, options: [CIDetectorAccuracy:CIDetectorAccuracyHigh])
      let features=detector.featuresInImage(ciImage)
      print("扫描到二维码个数：\(features.count)")
      //遍历所有的二维码，并框出
      for feature in features as! [CIQRCodeFeature] {
          print(feature.messageString)
      }

2，从相册中选择图片读取二维码

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//选取相册
//判断设置是否支持图片库
       if UIImagePickerController.isSourceTypeAvailable(.PhotoLibrary){
           //初始化图片控制器
           let picker = UIImagePickerController()
           //设置代理
           picker.delegate = self
           //指定图片控制器类型
           picker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
           //弹出控制器，显示界面
           self.presentViewController(picker, animated: true, completion: {
               () -> Void in
           })
       }else{
           print("读取相册错误")
       }

//选择图片成功后代理

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//选择图片成功后代理
  func imagePickerController(picker: UIImagePickerController,
      didFinishPickingMediaWithInfo info: [String : AnyObject]) {
      //获取选择的原图
      let image = info[UIImagePickerControllerOriginalImage] as! UIImage
      //二维码读取
      let ciImage:CIImage=CIImage(image:image)!
      let context = CIContext(options: nil)
      let detector:CIDetector=CIDetector(ofType: CIDetectorTypeQRCode,
          context: context, options: [CIDetectorAccuracy:CIDetectorAccuracyHigh])
      let features=detector.featuresInImage(ciImage)
      print("扫描到二维码个数：\(features.count)")
      //遍历所有的二维码，并框出
      for feature in features as! [CIQRCodeFeature] {
          print(feature.messageString)
      }
      //图片控制器退出
      picker.dismissViewControllerAnimated(true, completion: {
          () -> Void in
      })
  }

3，使用摄像头扫描读取二维码

（1）扫描主要使用的是AVFoundation，用起来方便简单

（2）通过 AVCaptureMetadataOutput 的 rectOfInterest 属性，可以设置探测探测区域。同时给这个探测区域添加个方框，只有在框中的二维码才会被扫描到。

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var scanRectView:UIView!
  var device:AVCaptureDevice!
  var input:AVCaptureDeviceInput!
  var output:AVCaptureMetadataOutput!
  var session:AVCaptureSession!
  var preview:AVCaptureVideoPreviewLayer!

//通过摄像头扫描

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do{
        self.device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
        self.input = try AVCaptureDeviceInput(device: device)
        self.output = AVCaptureMetadataOutput()
        output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
        self.session = AVCaptureSession()
        if UIScreen.mainScreen().bounds.size.height<500 {
            self.session.sessionPreset = AVCaptureSessionPreset640x480
        }else{
            self.session.sessionPreset = AVCaptureSessionPresetHigh
        }
        self.session.addInput(self.input)
        self.session.addOutput(self.output)
        self.output.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
        //计算中间可探测区域
        let windowSize:CGSize = UIScreen.mainScreen().bounds.size;
        let scanSize:CGSize = CGSizeMake(windowSize.width*3/4,
            windowSize.width*3/4);
        var scanRect:CGRect = CGRectMake((windowSize.width-scanSize.width)/2,
            (windowSize.height-scanSize.height)/2, scanSize.width, scanSize.height);
        //计算rectOfInterest 注意x,y交换位置
        scanRect = CGRectMake(scanRect.origin.y/windowSize.height,
            scanRect.origin.x/windowSize.width,
            scanRect.size.height/windowSize.height,
            scanRect.size.width/windowSize.width);
        //设置可探测区域
        self.output.rectOfInterest = scanRect
        self.preview = AVCaptureVideoPreviewLayer(session:self.session)
        self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill
        self.preview.frame = UIScreen.mainScreen().bounds
        self.view.layer.insertSublayer(self.preview, atIndex:0)
        //添加中间的探测区域绿框
        self.scanRectView = UIView();
        self.view.addSubview(self.scanRectView)
        self.scanRectView.frame = CGRectMake(0, 0, scanSize.width, scanSize.height);
        self.scanRectView.center = CGPointMake(
            CGRectGetMidX(UIScreen.mainScreen().bounds),
            CGRectGetMidY(UIScreen.mainScreen().bounds));
        self.scanRectView.layer.borderColor = UIColor.greenColor().CGColor
        self.scanRectView.layer.borderWidth = 1;
        //开始捕获
        self.session.startRunning()
    }catch _ as NSError{
        //打印错误消息
        let errorAlert = UIAlertView(title: "提醒",
            message: "请在iPhone的\"设置-隐私-相机\"选项中,允许本程序访问您的相机",
            delegate: self,
            cancelButtonTitle: "确定")
        errorAlert.show()
    }
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//摄像头捕获
   func captureOutput(captureOutput: AVCaptureOutput!,
       didOutputMetadataObjects metadataObjects: [AnyObject]!,
       fromConnection connection: AVCaptureConnection!) {
       var stringValue:String?
       if metadataObjects.count > 0 {
           let metadataObject = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
           stringValue = metadataObject.stringValue
           if stringValue != nil{
               self.session.stopRunning()
           }
       }
       self.session.stopRunning()
       //输出结果
       let alertView = UIAlertView(title: "二维码", message: stringValue,
           delegate: self, cancelButtonTitle: "确定")
       alertView.show()
   }

//消息框确认后消失

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    //消息框确认后消失
    func alertView(alertView: UIAlertView, willDismissWithButtonIndex buttonIndex: Int) {
         //继续扫描
         self.session.startRunning()
    }