iOS设置和获取二维码扫描

//
//  Copyright  2016年 hjl. All rights reserved.
//

#import "HHQrcodeController.h"
#import <AVFoundation/AVFoundation.h>

@interface HHQrcodeViewController () <AVCaptureMetadataOutputObjectsDelegate>

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

//* 预览图层 */
@property (nonatomic, weak) AVCaptureVideoPreviewLayer *previewLayer;

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection;
@end

@implementation HHQrcodeViewController 

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1. 实例化拍摄设备
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    // 2. 设置输入设备
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    // 3. 实例化拍摄元数据输出
    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
    // 4. 设置输出数据代理
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    // 5. 添加拍摄会话
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    self.session = session;
    // 6. 添加会话输入/输出
    if ([session canAddInput:input]) {
        [session addInput:input];
    }
    if ([session canAddOutput:output]) {
        [session addOutput:output];
    }
    //7 设置输出数据类型，需要将元数据输出添加到会话后，才能指定元数据类型，否则会报错
    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
    //8 实例化预览图层
    AVCaptureVideoPreviewLayer *previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session];
    previewLayer.frame = self.view.bounds;
    self.previewLayer = previewLayer;
    //9 将图层插入当前视图
    [self.view.layer insertSublayer:previewLayer atIndex:0];
    //10 启动会话
    [_session startRunning];
}

#pragma 代理
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{

    //1 判断是否获取到数据
    if (metadataObjects.count > 0) {
        //2 停止刷新
        [self.session stopRunning];
        //3 移除预览图层
        [self.previewLayer removeFromSuperlayer];
        //4 读取数据
        AVMetadataMachineReadableCodeObject *obj = [metadataObjects lastObject];
        HHLog(@"%@", obj.stringValue);
    }
}
@end