二维码扫描：ZBar,ZXing的使用

iOS二维码扫描开源库主要有Zbar和ZXing，在完成项目的过程中都用过，开始时用了Zbar，但其相对于ZXing扫描识别效率太低，无法达到项目要求，所以改用ZXing。两个开源库都可以识别二维码，但ZBar还支持条形码，ZXing识别条形码还需要改一些地方。一、ZBar的使用1.下载ZBar SDK，将ZBarSDK拖动到Xcode项目下载地址：https://github.com/bmorton/ZBarSDK2.添加framework框架

* AVFoundation.framework (weak)
* CoreMedia.framework (weak)
* CoreVideo.framework (weak)
* QuartzCore.framework

3.扫描代码引入头文件 #import  "ZBarSDK.h" ,实现ZBarReaderDelegate协议ZBarReaderViewController *reader = [ZBarReaderViewController new];reader.readerDelegate = self;reader.supportedOrientationsMask = ZBarOrientationMaskAll;ZBarImageScanner *scanner = reader.scanner;[scanner setSymbology: ZBAR_I25config: ZBAR_CFG_ENABLEto: 0];[self presentModalViewController:reader animated:YES];[reader release];扫描结果回调- (void) imagePickerController: (UIImagePickerController*) reader didFinishPickingMediaWithInfo: (NSDictionary*) info{id<NSFastEnumeration> results = [info objea21cctForKey: ZBarReaderControllerResults];ZBarSymbol *symbol = nil;for(symbol in results)break;text = symbol.data ;}还可以在ZBarReaderViewController自定义扫描界面和扫描区域（scanCrop）。二、ZXing的使用1.下载ZXIng，下载地址： https://github.com/zxing/zxing   .由于支持各种语言，整个工程比较大，IOS 只需保留cpp和iphone这2个文件夹，整个目录结构不变，cpp文件夹只保留cpp/core/src/zxing下面的内容，其余都可以全部删除。然后把删减好的zxing目录移动到我们的iOS项目的目录下(也可以右击选择Add files to‘project’)，并在

zxing/iphone/ZXingWidget/

目录下把

ZXingWidget.xcodeproj

拖动到我们的项目工程中。2.选择 target ——>Build Phases   在 Link Binary with Libraries里 添加

libZXingWidget.a，在Target Dependencies添加
ZXingWidget
。在target ——>Build Settings ——>Headers Search Path 添加两个路径：

.

/zxing/iphone/ZXingWidget/Classes./zxing/cpp/core/src第一个设成recursive ，第二个设成non-recursive添加一下frameworks 支持AVFoundationAudioToolboxCoreVideoCoreMedialibiconvAddressBookAddressBookUI3.扫描代码（1）直接引用头文件：#import <ZXingWidgetController.h>#import <QRCodeReader.h>扫描调用代码：ZXingWidgetController *widController = [[ZXingWidgetController alloc] initWithDelegate:self showCancel:YES OneDMode:NO];NSMutableSet *readers = [[NSMutableSet alloc] init];QRCodeReader *qrcodeReader = [[QRCodeReader alloc] init];[readers addObject:qrcodeReader];widController.readers = readers;[self presentViewController:widController animated:YES completion:^{}];扫描结果回调：@protocol ZXingDelegate- (void)zxingController:(ZXingWidgetController*)controller didScanResult:(NSString *)result;- (void)zxingControllerDidCancel:(ZXingWidgetController*)controller;@end还需要把引入的.m文件改为.mm。（2）自定义扫描我的项目要求中需要自定义扫描界面和扫描区域，还要加入C语言混编，所以就用了这种方法。头文件：#import <AssetsLibrary/AssetsLibrary.h>#import <QRCodeReader.h>#import <TwoDDecoderResult.h>#import <Decoder.h>初始化AVCapture- (void)initCapture{AVCaptureDevice* inputDevice =[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];AVCaptureDeviceInput *captureInput =[AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:nil];AVCaptureVideoDataOutput *captureOutput = [[AVCaptureVideoDataOutput alloc] init];captureOutput.alwaysDiscardsLateVideoFrames = YES;[captureOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];NSString* key = (NSString*)kCVPixelBufferPixelFormatTypeKey;NSNumber* value = [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA];NSDictionary* videoSettings = [NSDictionary dictionaryWithObject:value forKey:key];[captureOutput setVideoSettings:videoSettings];self.captureSession = [[[AVCaptureSession alloc] init] autorelease];NSString* preset = 0;if (NSClassFromString(@"NSOrderedSet") && // Proxy for "is this iOS 5" ...[UIScreen mainScreen].scale > 1 &&isIPad() &&[inputDevicesupportsAVCaptureSessionPreset:AVCaptureSessionPresetiFrame960x540]) {preset = AVCaptureSessionPresetiFrame960x540;}if (!preset) {preset = AVCaptureSessionPresetMedium;}self.captureSession.sessionPreset = preset;[self.captureSession addInput:captureInput];[self.captureSession addOutput:captureOutput];[captureOutput release];if (!self.prevLayer) {self.prevLayer = [AVCaptureVideoPreviewLayer layerWithSession:self.captureSession];}self.prevLayer.frame = self.view.bounds;self.prevLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;[self.view.layer addSublayer: self.prevLayer];[self.captureSession startRunning];} 得到AVCapture回调函数- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{if (!isScanning||delegate==nil) {return;}if (sampleBuffer){//将sampleBuffer转化为UIImageUIImage *image = [self imageFromSampleBuffer:sampleBuffer];//用Decoder来解析识别图像[self decodeImage:image];}}

- (void)decodeImage:(UIImage *)image
{
NSMutableSet *qrReader = [[NSMutableSet alloc] init];
QRCodeReader *qrcoderReader = [[QRCodeReader alloc] init];
[qrReader addObject:qrcoderReader];
[qrcoderReader release];

Decoder *decoder = [[Decoder alloc] init];
decoder.delegate = self;
decoder.readers = qrReader;
[decoder decodeImage:image];
[decoder release];
[qrReader release];
}

Decoder回调获得识别结果@optional- (void)decoder:(Decoder *)decoder willDecodeImage:(UIImage *)image usingSubset:(UIImage *)subset;- (void)decoder:(Decoder *)decoder didDecodeImage:(UIImage *)image usingSubset:(UIImage *)subset withResult:(TwoDDecoderResult *)result;- (void)decoder:(Decoder *)decoder failedToDecodeImage:(UIImage *)image usingSubset:(UIImage *)subset reason:(NSString *)reason;- (void)decoder:(Decoder *)decoder foundPossibleResultPoint:(CGPoint)point;注意扫描的画面不会跟着设备旋转，当横竖转换是需要改变画面CGFloat angle = 0.0f;switch (barOrientation){case UIInterfaceOrientationPortrait:angle = 0.0f;break;case UIInterfaceOrientationPortraitUpsideDown:angle = M_PI;break;case UIInterfaceOrientationLandscapeLeft:angle = M_PI / 2;break;case UIInterfaceOrientationLandscapeRight:angle = -M_PI / 2;break;default:break;}CATransform3D transform = CATransform3DMakeRotation(angle, 0, 0, 1.0);self.captureVideoPreviewLayer.transform =transform;self.captureVideoPreviewLayer.frame = layerframe;