一、生成二维码

1.首先要导入CoreImage框架

#import <Corelmage/CoreImage.h>

2.创建过滤器

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

3.设置过滤器为默认模式

[filtersetDefaults];

4.给过滤添加数据

NSString*dataString =@"http://www.jianshu.com/u/663e6f9b7f55";

NSData*data = [dataStringdataUsingEncoding:NSUTF8StringEncoding];

[filtersetValue:dataforKeyPath:@"inputMessage"];

5.获取输出的二维码

CIImage*outputImage = [filterout putImage];

6.显示二维码

self.imageView.image= [self  createNonInterpolatedUIImageFormCIImage:outputImage withSize:200];

7.为了展示清楚的二维码图片需要对outputImage做进一步处理

- (UIImage*)createNonInterpolatedUIImageFormCIImage:(CIImage*)image withSize:(CGFloat) size

{

CGRectextent =CGRectIntegral(image.extent);

CGFloatscale =MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

// 1.创建bitmap;

size_twidth =CGRectGetWidth(extent) * scale;

size_theight =CGRectGetHeight(extent) * scale;

CGColorSpaceRefcs =CGColorSpaceCreateDeviceGray();

CGContextRefbitmapRef =CGBitmapContextCreate(nil, width, height,8,0, cs, (CGBitmapInfo)kCGImageAlphaNone);

CIContext*context = [CIContextcontextWithOptions:nil];

CGImageRefbitmapImage = [contextcreateCGImage:imagefromRect:extent];

CGContextSetInterpolationQuality(bitmapRef,kCGInterpolationNone);

CGContextScaleCTM(bitmapRef, scale, scale);

CGContextDrawImage(bitmapRef, extent, bitmapImage);

// 2.保存bitmap到图片

CGImageRefscaledImage =CGBitmapContextCreateImage(bitmapRef);

CGContextRelease(bitmapRef);

CGImageRelease(bitmapImage);

return[UIImageimageWithCGImage:scaledImage];

}

二、扫描二维码

1.创建捕捉会话

AVCaptureSession*session = [[AVCaptureSessionalloc]init];

self.session= session;

 2.添加输入设备(数据从摄像头输入)

AVCaptureDevice*device = [AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];

AVCaptureDeviceInput*input = [AVCaptureDeviceInputdeviceInputWithDevice:deviceerror:nil];

[sessionaddInput:input];

 3.添加输出数据(示例对象-->类对象-->元类对象-->根元类对象)

AVCaptureMetadataOutput*output = [[AVCaptureMetadataOutput alloc]init];

[outputsetMetadataObjectsDelegate:selfqueue:dispatch_get_main_queue()];

[sessionaddOutput:output];

 3.1.设置输入元数据的类型(类型是二维码数据)

[outputsetMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];

4.添加扫描图层

AVCaptureVideoPreviewLayer*layer = [AVCaptureVideoPreviewLayerlayerWithSession:session];

layer.frame=self.view.bounds;

[self.view.layeraddSublayer:layer];

self.layer= layer;

 5.开始扫描

[sessionstartRunning];

6.实现output的回调方法

//当扫描到数据时就会执行该方法

- (void)captureOutput:(AVCaptureOutput*)captureOutput didOutputMetadataObjects:(NSArray*)metadataObjects fromConnection:(AVCaptureConnection*)connection

{

if(metadataObjects.count>0) {

AVMetadataMachineReadableCodeObject*object = [metadataObjects lastObject];

NSLog(@"%@", object.stringValue);

//停止扫描

[self.sessionstopRunning];

//将预览图层移除

[self.layer removeFromSuperlayer];

}else{

NSLog(@"没有扫描到数据");

}

}