ios---二维码的扫描

二维码扫描

• 使用ios的AVFoundation框架实现二维码扫描
• 第一步：设置相机访问权限；在Info.plist添加Privacy - Camera Usage Description权限
• 第二步：导入AVFoundation框架 #import <AVFoundation/AVFoundation.h>
• 第三步：签订AVCaptureMetadataOutputObjectsDelegate 协议
• 第四步：设置输入输出的中间桥梁

@property(nonatomic, strong)AVCaptureSession *session;/

• 第五步：扫描方法

 -(void)startScanWithSize:(CGFloat)sizeValue{
    AVCaptureDevice *device=[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    AVCaptureDeviceInput *input=[AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    if(input){
        AVCaptureMetadataOutput *output=[[AVCaptureMetadataOutput alloc]init];
        [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
        self.session=[[AVCaptureSession alloc]init];
        [_session setSessionPreset:AVCaptureSessionPresetHigh];
        [_session addInput:input];
        [_session addOutput:output];
        output.metadataObjectTypes=@[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code,AVMetadataObjectTypeEAN8Code,AVMetadataObjectTypeCode128Code];
        AVCaptureVideoPreviewLayer *layer=[AVCaptureVideoPreviewLayer layerWithSession:_session];
        layer.videoGravity=AVLayerVideoGravityResizeAspectFill;
        CGFloat xx=(self.view.bounds.size.width-sizeValue)/2;
        CGFloat yy=(self.view.bounds.size.height-sizeValue)/2;
        layer.frame=CGRectMake(xx, yy, sizeValue, sizeValue);
        [self.view.layer insertSublayer:layer atIndex:0];
        [_session startRunning];
    }
}

• 第六步：处理扫描结果

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
    if(metadataObjects.count>0){
        [_session stopRunning];
        AVMetadataMachineReadableCodeObject *metadataobject=[metadataObjects objectAtIndex:0];
        NSLog(@"%@",metadataobject.stringValue);
        AVCaptureVideoPreviewLayer *layer = (AVCaptureVideoPreviewLayer *)[[self.view.layer sublayers] objectAtIndex:0];
        [layer removeFromSuperlayer];
    }
}