扫描二维码的开源库有很多如 ZBar、ZXing等

ZBar的使用方法:

下载ZBar SDK

地址https://github.com/bmorton/ZBarSDK

ZBarSDK是一个开源的SDK，该SDK实现了识别和读取各种条形码，包括EAN-13/UPC-A, UPC-E, EAN-8, Code 128, Code 39, Interleaved 2 of 5 和 QR Code。

Step1.使用ZBarSDK 需要导入的framework

1.AVFoundation.framework

2.CoreMedia.framework

3.CoreVideo.framework

4.QuartzCore.framework

5.libiconv.dylib

Step2.在ViewController.h 导入#import "ZBarSDK.h"

Step3.在ViewController.h 实现 <ZBarReaderDelegate>协议

Step4.写代码：

- (IBAction)scan:(id)sender {

ZBarReaderViewController * reader = [ZBarReaderViewController new];

    reader.readerDelegate = self;

    ZBarImageScanner * scanner = reader.scanner;

    [scanner setSymbology:ZBAR_I25 config:ZBAR_CFG_ENABLE to:0];

    reader.showsZBarControls = YES;

    [self PResentViewController:reader animated:YES completion:nil];

}

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info

{

    id<NSFastEnumeration> results = [info objectForKey:ZBarReaderControllerResults];

    ZBarSymbol * symbol;

    for(symbol in results)

        break;

    _imageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];

    [picker dismissViewControllerAnimated:YES completion:nil];

    _label.text = symbol.data;

}