二維碼生成步驟：
1.導入CoreImage框架
2.通過濾鏡CIFilter生成二維碼
示例代碼：
?1.創建過濾器
CIFilter*filter = [CIFilterfilterWithName:@"CIQRCodeGenerator"];
2.恢復默認
[filtersetDefaults];
?3.給過濾器添加數據(正則表達式/賬號和密碼)
NSString*dataString =@"http://www.520it.com";
NSData*data = [dataStringdataUsingEncoding:NSUTF8StringEncoding];
[filtersetValue:dataforKeyPath:@"inputMessage"];
?4.獲取輸出的二維碼
CIImage*outputImage = [filteroutputImage];
?5.顯示二維碼
self.imageView.image= [selfcreateNonInterpolatedUIImageFormCIImage:outputImagewithSize:200];
在第五步顯示二維碼的時候用了一個自己封裝的方法（解決二維碼圖片不清晰）
具體方法如下：
/**
*根據CIImage生成指定大小的UIImage
*
*? @param image CIImage
*? @param size圖片寬度
*/
- (UIImage*)createNonInterpolatedUIImageFormCIImage:(CIImage*)image withSize:(CGFloat) size
{
CGRectextent =CGRectIntegral(image.extent);
CGFloatscale =MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
// 1.創建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到圖片
CGImageRefscaledImage =CGBitmapContextCreateImage(bitmapRef);
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
return[UIImageimageWithCGImage:scaledImage];
}
以上完整生成二維碼的代碼詳見gitHub:https://github.com/KimsLeo/joker2.git
二維碼掃描
// 1.創建捕捉會話
AVCaptureSession*session = [[AVCaptureSessionalloc]init];
self.session= session;
// 2.添加輸入設備(數據從攝像頭輸入)
AVCaptureDevice*device = [AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput*input = [AVCaptureDeviceInputdeviceInputWithDevice:deviceerror:nil];
[sessionaddInput:input];
// 3.添加輸出數據(示例對象-->類對象-->元類對象-->根元類對象)
AVCaptureMetadataOutput*output = [[AVCaptureMetadataOutputalloc]init];
[outputsetMetadataObjectsDelegate:selfqueue:dispatch_get_main_queue()];
[sessionaddOutput:output];
// 3.1.設置輸入元數據的類型(類型是二維碼數據)
[outputsetMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
// 4.添加掃描圖層
AVCaptureVideoPreviewLayer*layer = [AVCaptureVideoPreviewLayerlayerWithSession:session];
layer.frame=self.view.bounds;
[self.view.layeraddSublayer:layer];
self.layer= layer;
// 5.開始掃描
[sessionstartRunning];
掃描數據以后的方法回調（捕捉掃描數據）：
#pragma mark -實現output的回調方法
//當掃描到數據時就會執行該方法
- (void)captureOutput:(AVCaptureOutput*)captureOutput didOutputMetadataObjects:(NSArray*)metadataObjects fromConnection:(AVCaptureConnection*)connection
{
if(metadataObjects.count>0) {
AVMetadataMachineReadableCodeObject*object = [metadataObjectslastObject];
NSLog(@"%@", object.stringValue);
//停止掃描
[self.sessionstopRunning];
//將預覽圖層移除
[self.layerremoveFromSuperlayer];
}else{
NSLog(@"沒有掃描到數據");
}
}
掃描二維碼的完整代碼詳見gitHub:https://github.com/KimsLeo/joker2.git
