iOS二维码的生成和扫码详细介绍(手把手教)

CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

[filter setDefaults];

//存放的信息
NSString *info = @"我叫王冲";
//把信息转化为NSData
NSData *infoData = [info dataUsingEncoding:NSUTF8StringEncoding];
//滤镜对象kvc存值
[filter setValue:infoData forKeyPath:@"inputMessage"];
//我们可以打印,看过滤器的 输入属性.这样我们才知道给谁赋值
 NSLog(@"%@",qrImageFilter.inputKeys);
 /*
    inputMessage,        //二维码输入信息
    inputCorrectionLevel //二维码错误的等级,就是容错率
  */

CIImage *outImage = [filter outputImage];

imageView.image = [self createNonInterpolatedUIImageFormCIImage:outImage withSize:300];
/**
 *  根据CIImage生成指定大小的UIImage
 *
 *  @param image CIImage
 *  @param size  图片宽度以及高度
 */
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
{
  CGRect extent = CGRectIntegral(image.extent);
  CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
  //1.创建bitmap;
  size_t width = CGRectGetWidth(extent) * scale;
  size_t height = CGRectGetHeight(extent) * scale;
  CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
  CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
  CIContext *context = [CIContext contextWithOptions:nil];
  CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
  CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
  CGContextScaleCTM(bitmapRef, scale, scale);
  CGContextDrawImage(bitmapRef, extent, bitmapImage);
  //2.保存bitmap到图片
  CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
  CGContextRelease(bitmapRef);
  CGImageRelease(bitmapImage);
  return [UIImage imageWithCGImage:scaledImage];
}

1.导入:SDWebImage 框架
 2.拖入我封装好的类 ,导入 #import "LogoQR.h"
 3.创建UIImageView的对象来放二维码
 4.调用方法
  /**
 *  [LogoQR new] 调用方法的对象
 *  QRurl :头像的链接
 *  messages: 二维码里面存放的信息
 */
UIImageView的对象.image = [[LogoQR new] QRurl:urlString
                             messages:self.messages];

<1>.获取捕捉会话(AVFoundation框架)
 <2>.设置输入摄像头
 <3>.设置输出数据
 <4>.添加预览图层
 <5>.开始扫描二维码

AVCaptureSession *session = [[AVCaptureSession alloc]init];
self.session = session;

//AVMediaTypeVideo:摄像头, AVMediaTypeAudio:话筒, AVMediaTypeMuxed:弹幕
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (error) {
  //防止模拟器崩溃
  NSLog(@"没有摄像头设备");
  return;
}
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
[session addInput:input];

<AVCaptureMetadataOutputObjectsDelegate> 挂代理 
AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc]init];
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[session addOutput:output];
//设置输出类型,必须在output 加入到会话之后来设置
[output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];

AVCaptureVideoPreviewLayer *layer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:session];
layer.frame = self.view.bounds;
[self.view.layer addSublayer:layer];
self.layer = layer;

[session startRunning];

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
  if (metadataObjects.count>0)
   {
      //1.获取到扫描的内容
      AVMetadataMachineReadableCodeObject *object = [metadataObjects lastObject];
      NSLog(@"扫描的内容==%@",object.stringValue);
      //2.停止会话
      [self.session stopRunning];
      //3.移除预览图层
      [self.layer removeFromSuperlayer];
    }
}