如何实现扫码

//引入#import <AVFoundation/AVFoundation.h>头文件

//获取摄像设备

AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

//创建输入流

AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];

if (!input) return;

//创建输出流

AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];

output.rectOfInterest = CGRectMake(0.1, 0, 0.9, 1);

//设置代理 在主线程里刷新

[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

//初始化链接对象

_session = [[AVCaptureSession alloc]init];

//高质量采集率

[_session setSessionPreset:AVCaptureSessionPresetHigh];

[_session addInput:input];

[_session addOutput:output];

//设置扫码支持的编码格式(如下设置条形码和二维码兼容)

output.metadataObjectTypes=@[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code];

AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:_session];

layer.videoGravity=AVLayerVideoGravityResizeAspectFill;

layer.frame=self.view.layer.bounds;

[self.view.layer insertSublayer:layer atIndex:0];

//开始捕获

[_session startRunning];