IOS 二维码扫描

这篇博客是对上篇博客的补充，内容较少。

由于二维码扫描需要在真机上测试本人比较烂就不做效果图了。

下面是代码（代码中已经写了很清楚的注释）

//
//  ViewController.m
//  CX 二维码扫描
//
//  Created by ma c on 16/4/12.
//  Copyright © 2016年 bjsxt. All rights reserved.
//

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>

@end

@implementation ViewController

- (void)viewDidLoad {
    
    
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    
    //创建捕捉会话
    AVCaptureSession * session = [[AVCaptureSession alloc]init];
    //添加输入设备
    AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:@"AVMediaTypeVideo"];
    AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    [session addInput:input];
    //添加输出数据
    AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    [session addOutput:output];
    //告诉元数据类型为二维码类型
    //注意该方法在add后 否则崩溃
    //测试需要真机稍有麻烦 就不截图了
    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
    //添加扫描图层
    AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:session];
    layer.frame = CGRectMake(10,20, self.view.frame.size.width, 400);
    [self.view.layer addSublayer:layer];
    //开始扫描
    [session startRunning];
    
    //下面的方法适当的时候操作
    //停止扫描
//    [session stopRunning];
    //移除图层
//    [layer removeFromSuperlayer];
}
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
    //metadataObjects 为扫描的后的数据
    
    AVMetadataMachineReadableCodeObject * objc = [metadataObjects lastObject];
    //我们想要的结果
    NSLog(@"%@",objc.stringValue);
}
@end