iOS开发-QRCode-二维码识别与生成

jopen 9年前

有关二维码的介绍,我这里不做过多说明, 可以直接去基维百科查看,附上链接 QR code .

IOS7之前,开发者进行扫码编程时,一般会借助第三方库。常用的是 ZBarSDKaZXingObjC ,IOS7之后,系统的AVMetadataObject类中,为我们提供了解析二维码的接口。经过测试,使用原生API扫描和处理的效率非常高,远远高于第三方库。

扫描

官方提供的接口非常简单,直接看代码,主要使用的是AVFoundation。

@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>//用于处理采集信息的代理  {      AVCaptureSession * session;//输入输出的中间桥梁  }  @end  @implementation ViewController     - (void)viewDidLoad {      [super viewDidLoad];      // Do any additional setup after loading the view, typically from a nib.      //获取摄像设备      AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];      //创建输入流      AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];      if (!input) return;      //创建输出流      AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];      //设置代理 在主线程里刷新      [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];      //设置有效扫描区域      CGRect scanCrop=[self getScanCrop:_scanWindow.bounds readerViewBounds:self.view.frame];       output.rectOfInterest = scanCrop;      //初始化链接对象      _session = [[AVCaptureSession alloc]init];      //高质量采集率      [_session setSessionPreset:AVCaptureSessionPresetHigh];            [_session addInput:input];      [_session addOutput:output];      //设置扫码支持的编码格式(如下设置条形码和二维码兼容)      output.metadataObjectTypes=@[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code];            AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:_session];      layer.videoGravity=AVLayerVideoGravityResizeAspectFill;      layer.frame=self.view.layer.bounds;      [self.view.layer insertSublayer:layer atIndex:0];      //开始捕获      [_session startRunning];  }    -(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{      if (metadataObjects.count>0) {          //[session stopRunning];          AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex : 0 ];          //输出扫描字符串          NSLog(@"%@",metadataObject.stringValue);      }  }
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一些初始化的代码加上实现代理方法便完成了二维码扫描的工作,这里我们需要注意的是, 在二维码扫描的时候, 我们一般都会在屏幕中间放一个方框,用来显示二维码扫描的大小区间,这里我们在个 AVCaptureMetadataOutput 类中有一个 rectOfInterest 属性,它的作用就是设置扫描范围。

这个CGRect参数和普通的Rect范围不太一样,它的四个值的范围都是0-1,表示比例。

rectOfInterest都是按照横屏来计算的 所以当竖屏的情况下 x轴和y轴要交换一下。

宽度和高度设置的情况也是类似。

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我们在上面设置有效扫描区域的方法如下

#pragma mark-> 获取扫描区域的比例关系  -(CGRect)getScanCrop:(CGRect)rect readerViewBounds:(CGRect)readerViewBounds  {            CGFloat x,y,width,height;            x = (CGRectGetHeight(readerViewBounds)-CGRectGetHeight(rect))/2/CGRectGetHeight(readerViewBounds);      y = (CGRectGetWidth(readerViewBounds)-CGRectGetWidth(rect))/2/CGRectGetWidth(readerViewBounds);      width = CGRectGetHeight(rect)/CGRectGetHeight(readerViewBounds);      height = CGRectGetWidth(rect)/CGRectGetWidth(readerViewBounds);            return CGRectMake(x, y, width, height);        }
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读取

读取主要用到CoreImage 不过要强调的是读取二维码的功能只有在iOS8之后才支持,我们需要在相册中调用一个二维码,将其读取,代码如下

#pragma mark-> 我的相册  -(void)myAlbum{            NSLog(@"我的相册");      if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){          //1.初始化相册拾取器          UIImagePickerController *controller = [[UIImagePickerController alloc] init];          //2.设置代理          controller.delegate = self;          //3.设置资源:          /**           UIImagePickerControllerSourceTypePhotoLibrary,相册           UIImagePickerControllerSourceTypeCamera,相机           UIImagePickerControllerSourceTypeSavedPhotosAlbum,照片库           */          controller.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;          //4.随便给他一个转场动画          controller.modalTransitionStyle=UIModalTransitionStyleFlipHorizontal;          [self presentViewController:controller animated:YES completion:NULL];                }else{                    UIAlertView * alert = [[UIAlertView alloc]initWithTitle:@"提示" message:@"设备不支持访问相册,请在设置->隐私->照片中进行设置!" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];          [alert show];      }        }
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完成相册代理, 我们在代理中添加读取二维码方法

#pragma mark-> imagePickerController delegate  - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info  {      //1.获取选择的图片      UIImage *image = info[UIImagePickerControllerOriginalImage];      //2.初始化一个监测器      CIDetector*detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{ CIDetectorAccuracy : CIDetectorAccuracyHigh }];            [picker dismissViewControllerAnimated:YES completion:^{          //监测到的结果数组          NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:image.CGImage]];          if (features.count >=1) {              /**结果对象 */              CIQRCodeFeature *feature = [features objectAtIndex:0];              NSString *scannedResult = feature.messageString;              UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"扫描结果" message:scannedResult delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];              [alertView show];                      }          else{              UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"提示" message:@"该图片没有包含一个二维码!" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];              [alertView show];                        }                    }];              }
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因为没用真机,所以这里没有给出太多的截图, 用模拟器读取自带图片,结果如下

生成

生成二维码,其实也是用到CoreImage,但是步骤繁琐一些,代码如下

#pragma mark-> 二维码生成  -(void)create{            UIImage *image=[UIImage imageNamed:@"6824500_006_thumb.jpg"];      NSString*tempStr;      if(self.textField.text.length==0){                    tempStr=@"ddddddddd";                }else{                    tempStr=self.textField.text;                }      UIImage*tempImage=[QRCodeGenerator qrImageForString:tempStr imageSize:360 Topimg:image withColor:RandomColor];            _outImageView.image=tempImage;        }  +(UIImage*)qrImageForString:(NSString *)string imageSize:(CGFloat)size Topimg:(UIImage *)topimg withColor:(UIColor*)color{            if (![string length]) {          return nil;      }            QRcode *code = QRcode_encodeString([string UTF8String], 0, QR_ECLEVEL_L, QR_MODE_8, 1);      if (!code) {          return nil;      }            // create context      CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();      CGContextRef ctx = CGBitmapContextCreate(0, size, size, 8, size * 4, colorSpace, kCGImageAlphaPremultipliedLast);            CGAffineTransform translateTransform = CGAffineTransformMakeTranslation(0, -size);      CGAffineTransform scaleTransform = CGAffineTransformMakeScale(1, -1);      CGContextConcatCTM(ctx, CGAffineTransformConcat(translateTransform, scaleTransform));            // draw QR on this context      [QRCodeGenerator drawQRCode:code context:ctx size:size withPointType:0 withPositionType:0 withColor:color];            // get image      CGImageRef qrCGImage = CGBitmapContextCreateImage(ctx);      UIImage * qrImage = [UIImage imageWithCGImage:qrCGImage];            if(topimg)      {          UIGraphicsBeginImageContext(qrImage.size);                    //Draw image2          [qrImage drawInRect:CGRectMake(0, 0, qrImage.size.width, qrImage.size.height)];                    //Draw image1          float r=qrImage.size.width*35/240;          [topimg drawInRect:CGRectMake((qrImage.size.width-r)/2, (qrImage.size.height-r)/2 ,r, r)];            qrImage=UIGraphicsGetImageFromCurrentImageContext();                    UIGraphicsEndImageContext();      }        // some releases      CGContextRelease(ctx);      CGImageRelease(qrCGImage);      CGColorSpaceRelease(colorSpace);      QRcode_free(code);            return qrImage;          }  + (void)drawQRCode:(QRcode *)code context:(CGContextRef)ctx size:(CGFloat)size withPointType:(QRPointType)pointType withPositionType:(QRPositionType)positionType withColor:(UIColor *)color {   unsigned char *data = 0;   int width;   data = code->data;   width = code->width;   float zoom = (double)size / (code->width + 2.0 * qr_margin);   CGRect rectDraw = CGRectMake(0, 0, zoom, zoom);         // draw      const CGFloat *components;      if (color) {          components = CGColorGetComponents(color.CGColor);      }else {          components = CGColorGetComponents([UIColor blackColor].CGColor);      }      CGContextSetRGBFillColor(ctx, components[0], components[1], components[2], 1.0);      NSLog(@"aad :%f  bbd :%f   ccd:%f",components[0],components[1],components[2]);      for(int i = 0; i < width; ++i) {    for(int j = 0; j < width; ++j) {     if(*data & 1) {      rectDraw.origin = CGPointMake((j + qr_margin) * zoom,(i + qr_margin) * zoom);                  if (positionType == QRPositionNormal) {                      switch (pointType) {                          case QRPointRect:                              CGContextAddRect(ctx, rectDraw);                              break;                          case QRPointRound:                              CGContextAddEllipseInRect(ctx, rectDraw);                              break;                          default:                              break;                      }                  }else if(positionType == QRPositionRound) {                      switch (pointType) {                          case QRPointRect:                              CGContextAddRect(ctx, rectDraw);                              break;                          case QRPointRound:                              if ((i>=0 && i<=6 && j>=0 && j<=6) || (i>=0 && i<=6 && j>=width-7-1 && j<=width-1) || (i>=width-7-1 && i<=width-1 && j>=0 && j<=6)) {                                  CGContextAddRect(ctx, rectDraw);                              }else {                                  CGContextAddEllipseInRect(ctx, rectDraw);                              }                              break;                          default:                              break;                      }                  }     }     ++data;    }   }   CGContextFillPath(ctx);  }
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在textField输入,生成下图

长按二维码识别

这个功能有很多的地方在用, 最让人熟知的我想便是微信了,其实实现方法还是很简单的。

 #pragma mark-> 长按识别二维码  -(void)dealLongPress:(UIGestureRecognizer*)gesture{            if(gesture.state==UIGestureRecognizerStateBegan){                    _timer.fireDate=[NSDate distantFuture];                    UIImageView*tempImageView=(UIImageView*)gesture.view;          if(tempImageView.image){              //1. 初始化扫描仪,设置设别类型和识别质量              CIDetector*detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{ CIDetectorAccuracy : CIDetectorAccuracyHigh }];              //2. 扫描获取的特征组              NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:tempImageView.image.CGImage]];              //3. 获取扫描结果              CIQRCodeFeature *feature = [features objectAtIndex:0];              NSString *scannedResult = feature.messageString;              UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"扫描结果" message:scannedResult delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];              [alertView show];          }else {                            UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"扫描结果" message:@"您还没有生成二维码" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];              [alertView show];          }                          }else if (gesture.state==UIGestureRecognizerStateEnded){                              _timer.fireDate=[NSDate distantPast];      }              }
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我们用刚才生成的二维码进行长按识别,效果如下

结语

本文demo下载地址请点这里 Demo ,

转自 mokey1422 所写的仿支付宝二维码。

系统原生的二维码扫描扫描识别速度,要比第三方好用得多,在没有特殊原因的情况下,比如7.0系统以下,我希望大家都能用系统原生的方法。

文章若有问题请给予指正,感谢。

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来自: http://yimouleng.com/2016/01/13/ios-QRCode/