iOS7之前，开发者进行扫码编程时，一般会借助第三方库。扫描二维码 OC 的开源库有 ZBar和ZXing，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。
在开始之前最重要的一步是要先导入原生的音视频框架即 AVFoundation.framework 。 以下是笔者封装的二维码扫描视图QRView
QRView.h 头文件
#import <UIKit/UIKit.h> @class QRView; @protocol QRViewDelegate <NSObject> /** * 代理回调扫描结果 * * @param view 扫一扫视图 * @param result 扫描结果 */ - (void)qrView:(QRView*)view ScanResult:(NSString*)result; @end @interface QRView : UIView @property(nonatomic,assign)id<QRViewDelegate> delegate; @property(nonatomic,assign,readonly)CGRect scanViewFrame; - (void)startScan; - (void)stopScan; @endQRView.m 实现文件
#import "QRView.h" #import <AVFoundation/AVFoundation.h> @interface QRView ()<AVCaptureMetadataOutputObjectsDelegate> @end @implementation QRView { AVCaptureSession *_session; UIImageView *_scanView; UIImageView *_lineView; } - (instancetype)initWithFrame:(CGRect)frame{ self = [super initWithFrame:frame]; if (self) { [self initView]; } return self; } - (void)initView { UIImage *scanImage = [UIImage imageNamed:@"scanscanBg"]; CGFloat width = CGRectGetWidth(self.frame); CGFloat height = CGRectGetHeight(self.frame); CGFloat scanW = 200; CGRect scanFrame = CGRectMake(width/2.-100, height/2.-100, scanW, scanW); _scanViewFrame = scanFrame; _scanView = [[UIImageView alloc]initWithImage:scanImage]; _scanView.backgroundColor = [UIColor clearColor]; _scanView.frame = scanFrame; [self addSubview:_scanView]; //获取摄像设备 AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; //闪光灯 if ([device hasFlash] && [device hasTorch]) { [device lockForConfiguration:nil]; [device setFlashMode:AVCaptureFlashModeAuto]; [device setTorchMode:AVCaptureTorchModeAuto]; [device unlockForConfiguration]; } //创建输入流 AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil]; //创建输出流 AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc]init]; //设置代理 刷新线程 [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()]; output.rectOfInterest = [self rectOfInterestByScanViewRect:_scanView.frame]; //初始化连接对象 _session = [[AVCaptureSession alloc]init]; //采集率 _session.sessionPreset = AVCaptureSessionPresetHigh; if (input) { [_session addInput:input]; } if (output) { [_session addOutput:output]; //设置扫码支持的编码格式 NSMutableArray *array = [[NSMutableArray alloc]initWithCapacity:0]; if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeQRCode]) { [array addObject:AVMetadataObjectTypeQRCode]; } if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN13Code]) { [array addObject:AVMetadataObjectTypeEAN13Code]; } if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN8Code]) { [array addObject:AVMetadataObjectTypeEAN8Code]; } if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeCode128Code]) { [array addObject:AVMetadataObjectTypeCode128Code]; } output.metadataObjectTypes = array; } AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:_session]; layer.videoGravity = AVLayerVideoGravityResizeAspectFill; layer.frame = self.bounds; [self.layer insertSublayer:layer above:0]; [self bringSubviewToFront:_scanView]; [self setOverView]; [_session startRunning]; [self loopDrawLine]; } //设置扫描区域 - (CGRect)rectOfInterestByScanViewRect:(CGRect)rect{ CGFloat width = CGRectGetWidth(self.frame); CGFloat height = CGRectGetHeight(self.frame); CGFloat x = (height - CGRectGetHeight(rect))/2/height; CGFloat y = (width - CGRectGetWidth(rect))/2/width; CGFloat w = CGRectGetHeight(rect)/height; CGFloat h = CGRectGetWidth(rect)/width; return CGRectMake(x, y, w, h); } #pragma mark - 添加模糊效果 - (void)setOverView { CGFloat width = CGRectGetWidth(self.frame); CGFloat height = CGRectGetHeight(self.frame); CGFloat x = CGRectGetMinX(_scanView.frame); CGFloat y = CGRectGetMinY(_scanView.frame); CGFloat w = CGRectGetWidth(_scanView.frame); CGFloat h = CGRectGetHeight(_scanView.frame); [self creatView:CGRectMake(0, 0, width, y)]; [self creatView:CGRectMake(0, y + h, width, height - y)]; [self creatView:CGRectMake(0, y, x, h)]; [self creatView:CGRectMake(x + w, y, x, h)]; } - (void)creatView:(CGRect)rect{ CGFloat alpha = 0.5; UIView *view = [[UIView alloc]initWithFrame:rect]; view.backgroundColor = [UIColor grayColor]; view.alpha = alpha; [self addSubview:view]; } #pragma mark - 动画 - (void)loopDrawLine { UIImage *lineImage = [UIImage imageNamed:@"scanLine"]; CGFloat x = CGRectGetMinX(_scanView.frame); CGFloat y = CGRectGetMinY(_scanView.frame); CGFloat w = CGRectGetWidth(_scanView.frame); CGFloat h = CGRectGetHeight(_scanView.frame); CGRect start = CGRectMake(x, y, w, 2); CGRect end = CGRectMake(x, y + h - 2, w, 2); if (!_lineView) { _lineView = [[UIImageView alloc]initWithImage:lineImage]; _lineView.frame = start; [self addSubview:_lineView]; }else{ _lineView.frame = start; } __weak typeof(self) weakSelf = self; [UIView animateWithDuration:2 animations:^{ _lineView.frame = end; } completion:^(BOOL finished) { [weakSelf loopDrawLine]; }]; } #pragma mark - AVCaptureMetadataOutputObjectsDelegate - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection { if (metadataObjects.count>0) { AVMetadataMachineReadableCodeObject *metadataObject = [metadataObjects firstObject]; if ([_delegate respondsToSelector:@selector(qrView:ScanResult:)]) { [_delegate qrView:self ScanResult:metadataObject.stringValue]; } } } - (void)startScan{ _lineView.hidden = NO; [_session startRunning]; } - (void)stopScan{ _lineView.hidden = YES; [_session stopRunning]; } @end调用示例:
- (void)viewDidLoad { [super viewDidLoad]; self.view.backgroundColor = [UIColor whiteColor]; QRView *qrView = [[QRView alloc]initWithFrame:self.view.bounds]; qrView.delegate = self; [self.view addSubview:qrView]; } //代理回调扫描结果 - (void)qrView:(QRView *)view ScanResult:(NSString *)result { [view stopScan]; NSLog(@"扫描结果:%@",result); } 扫一扫示例图片生成二维码UIImage+QRCode
UIImage+QRCode.h 文件
#import <UIKit/UIKit.h> @interface UIImage (QRCode) + (UIImage *)qrImageByContent:(NSString *)content; //pre + (UIImage *)qrImageWithContent:(NSString *)content size:(CGFloat)size; /** * 色值 0~255 */ + (UIImage *)qrImageWithContent:(NSString *)content size:(CGFloat)size red:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue; + (UIImage *)qrImageWithContent:(NSString *)content logo:(UIImage *)logo size:(CGFloat)size red:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue; @endUIImage+QRCode.m 文件
#import "UIImage+QRCode.h" #import <AVFoundation/AVFoundation.h> @implementation UIImage (QRCode) void ProviderReleaseData (void *info, const void *data, size_t size){ free((void*)data); } + (CIImage *)qrByContent:(NSString *)content { CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"]; NSData *stringData = [content dataUsingEncoding:NSUTF8StringEncoding]; [qrFilter setValue:stringData forKey:@"inputMessage"]; [qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"]; CIImage *image = qrFilter.outputImage; return image; } + (UIImage *)qrImageWithContent:(NSString *)content size:(CGFloat)size { CIImage *image = [UIImage qrByContent:content]; CGRect extent = CGRectIntegral(image.extent); CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent)); // 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); // 保存bitmap到图片 CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef); CGContextRelease(bitmapRef); CGImageRelease(bitmapImage); return [UIImage imageWithCGImage:scaledImage]; } + (UIImage *)qrImageWithContent:(NSString *)content size:(CGFloat)size red:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue { UIImage *image = [UIImage qrImageWithContent:content size:size]; const int imageWidth = image.size.width; const int imageHeight = image.size.height; size_t bytesPerRow = imageWidth * 4; uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast); CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage); // 遍历像素 int pixelNum = imageWidth * imageHeight; uint32_t* pCurPtr = rgbImageBuf; for (int i = 0; i < pixelNum; i++, pCurPtr++){ if ((*pCurPtr & 0xFFFFFF00) < 0x99999900) // 将白色变成透明 { // 改成下面的代码，会将图片转成想要的颜色 uint8_t* ptr = (uint8_t*)pCurPtr; ptr[3] = red; //0~255 ptr[2] = green; ptr[1] = blue; } else { uint8_t* ptr = (uint8_t*)pCurPtr; ptr[0] = 0; } } // 输出图片 CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData); CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpace, kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider, NULL, true, kCGRenderingIntentDefault); CGDataProviderRelease(dataProvider); UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef]; // 清理空间 CGImageRelease(imageRef); CGContextRelease(context); CGColorSpaceRelease(colorSpace); return resultUIImage; } + (UIImage *)qrImageWithContent:(NSString *)content logo:(UIImage *)logo size:(CGFloat)size red:(NSInteger)red green:(NSInteger)green blue:(NSInteger)blue { UIImage* resultUIImage = [self qrImageWithContent:content size:size red:red green:green blue:blue]; // 添加logo CGFloat logoW = resultUIImage.size.width / 5.; CGRect logoFrame = CGRectMake(logoW * 2, logoW * 2, logoW, logoW); UIGraphicsBeginImageContext(resultUIImage.size); [resultUIImage drawInRect:CGRectMake(0, 0, resultUIImage.size.width, resultUIImage.size.height)]; [logo drawInRect:logoFrame]; UIImage *kk = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return kk; } + (UIImage *)qrImageByContent:(NSString *)content { NSData *stringData = [content dataUsingEncoding:NSUTF8StringEncoding]; CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"]; [qrFilter setValue:stringData forKey:@"inputMessage"]; [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"]; CIImage *qrImage = qrFilter.outputImage; CGSize size = CGSizeMake(300, 300); CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:qrImage fromRect:qrImage.extent]; UIGraphicsBeginImageContext(size); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetInterpolationQuality(context, kCGInterpolationNone); CGContextScaleCTM(context, 1, -1); CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage); UIImage *codeImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); CGImageRelease(cgImage); return codeImage; } @end调用示例:
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectZero]; imgView.frame = CGRectMake(0, 0, 200, 200); imgView.center = self.view.center; imgView.layer.shadowColor = [UIColor blackColor].CGColor; imgView.layer.shadowOffset = CGSizeMake(1, 2); imgView.layer.shadowRadius = 1; imgView.layer.shadowOpacity = 0.5; [self.view addSubview:imgView]; imgView.image = [UIImage qrImageByContent:@"www.baidu.com"]; 生成的二维码示例
