在iOS7以后,AVFoundation中就添加了QR Code部分，QR是指Quick Response 。
首先，要引入
#import <AVFoundation/AVFoundation.h>
创建两个对象
//捕捉会话
@property (nonatomic, strong) AVCaptureSession *captureSession;
//展示layer
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;
记得，在viewDidLoad中将captureSession开始设置为nil。
现在开始扫描的主体部分
- (BOOL)startReading {
NSError *error;
//初始化捕捉设备（AVCaptureDevice），类型为AVMediaTypeVideo,该类型可以快速使用设备的摄像头部分
AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
//用captureDevice创建输入流
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
if (!input) {
NSLog(@"%@", [error localizedDescription]);
return NO;
}
//创建媒体数据输出流
AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
//实例化捕捉会话
_captureSession = [[AVCaptureSession alloc] init];
//将输入流添加到会话
[_captureSession addInput:input];
//将媒体输出流添加到会话中
[_captureSession addOutput:captureMetadataOutput];
//创建串行队列，并加媒体输出流添加到队列当中
dispatch_queue_t dispatchQueue;
dispatchQueue = dispatch_queue_create("myQueue", NULL);
//设置代理
[captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
//设置输出媒体数据类型为QRCode
[captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];
//实例化预览图层
_videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
//设置预览图层填充方式
[_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
//设置图层的frame
[_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
//将图层添加到预览view的图层上
[_viewPreview.layer addSublayer:_videoPreviewLayer];
//设置扫描范围
captureMetadataOutput.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);
//扫描框
_boxView = [[UIView alloc] initWithFrame:CGRectMake(_viewPreview.bounds.size.width * 0.2f, _viewPreview.bounds.size.height * 0.2f, _viewPreview.bounds.size.width - _viewPreview.bounds.size.width * 0.4f, _viewPreview.bounds.size.height - _viewPreview.bounds.size.height * 0.4f)];
_boxView.layer.borderColor = [UIColor greenColor].CGColor;
_boxView.layer.borderWidth = 1.0f;
[_viewPreview addSubview:_boxView];
//扫描线
_scanLayer = [[CALayer alloc] init];
_scanLayer.frame = CGRectMake(0, 0, _boxView.bounds.size.width, 1);
_scanLayer.backgroundColor = [UIColor blueColor].CGColor;
[_boxView.layer addSublayer:_scanLayer];
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.2f target:self selector:@selector(moveScanLayer:) userInfo:nil repeats:YES];
[timer fire];
//开始扫描
[_captureSession startRunning];
return YES;
}
}
关于扫描框和扫描线，这些其实是可以去掉的，设置扫描范围后只要二维码进入到范围内就可以获取到相应的信息。所以这一块可以根据自己的喜好进行设置，扫描线只要设置一个定时器然后让线不断上下移动就行了。
停止扫描
[_captureSession stopRunning];
_captureSession = nil;
[_scanLayer removeFromSuperlayer];
[_videoPreviewLayer removeFromSuperlayer];
扫描二维码后进入相应的方法
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
//判断是否有数据
if (metadataObjects != nil && [metadataObjects count] > 0) {
AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];
//判断回传的数据类型
if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {
//对获取信息进行处理
}
}
}
这样就实现了二维码扫描的功能
再就是关于二维码的生成
首先创建一个UIImageVIew对象
@property (weak, nonatomic) IBOutlet UIImageView *image;
生成二维码，我这里是默认将字符串设置了生成二维码
//生成二维码
- (UIImage *)generateQRCode:(NSString *)str width:(CGFloat)width height:(CGFloat)height {
// 生成二维码图片
CIImage *qrcodeImage;
NSData *data = [str dataUsingEncoding:NSISOLatin1StringEncoding allowLossyConversion:false];
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[filter setValue:data forKey:@"inputMessage"];
[filter setValue:@"H" forKey:@"inputCorrectionLevel"];
qrcodeImage = [filter outputImage];
// 消除模糊
CGFloat scaleX = width / qrcodeImage.extent.size.width; // extent 返回图片的frame
CGFloat scaleY = height / qrcodeImage.extent.size.height;
CIImage *transformedImage = [qrcodeImage imageByApplyingTransform:CGAffineTransformScale(CGAffineTransformIdentity, scaleX, scaleY)];
return [UIImage imageWithCIImage:transformedImage];
}
最后将返回的图片显示到相应的位置就可以了
