注意：本篇文章采用了IOS7的新特性来扫二维码，所以系统支持要IOS7以上，如果要兼容IOS7之前的版本，自行找库来支持。

为了方便，我把扫二维码简单封装到了一个UIView中，用代理的方式返回值

在使用之前，应当为工程添加AVFoundation.framework

最后实现的效果如图

完整的实现代码

头文件

//  //  HwcScanQRView.h  //  HwcAnimationExample  //  //  Created by huangwenchen on 15/1/7.  //  Copyright (c) 2015年 huangwenchen. All rights reserved.  //    #import <UIKit/UIKit.h>    @protocol HwcScanQRDelegate <NSObject>  /*!  * @discussion Delegate method when scan QR successed  * @param QRContent Scan result  * @return Void  */    -(void)DidGetScanWithResult:(NSString *)QRContent;  /*!   * @discussion Delegate method when scan QR failed   * @param error Error message   * @return Void   */  -(void)DidFailToScanWithError:(NSError *)error;  @end    @interface HwcScanQRView : UIView  @property id<HwcScanQRDelegate> delegate;  @property(nonatomic,readonly) bool isScaning;  -(BOOL)startScaning;  -(void)stop;  @end  

.m文件

//  //  HwcScanQRView.m  //  HwcAnimationExample  //  //  Created by huangwenchen on 15/1/7.  //  Copyright (c) 2015年 huangwenchen. All rights reserved.  //    #import "HwcScanQRView.h"  #import  <AVFoundation/AVFoundation.h>  @interface HwcScanQRView()<AVCaptureMetadataOutputObjectsDelegate>    @property(nonatomic,readwrite) bool isScaning;  @property(strong,nonatomic)AVCaptureSession * captureSession;  @property(strong,nonatomic)AVCaptureVideoPreviewLayer * vedioPreviewLayer;  @end    @implementation HwcScanQRView    #pragma mark - Propertys  -(AVCaptureSession *)captureSession{      if (!_captureSession) {          _captureSession = [[AVCaptureSession alloc] init];      }      return  _captureSession;  }    -(AVCaptureVideoPreviewLayer *)vedioPreviewLayer{      if (!_vedioPreviewLayer) {          _vedioPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];      }      return _vedioPreviewLayer;  }  #pragma mark - QRScan function  -(BOOL)startScaning{      NSError * error;      AVCaptureDevice * captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];      AVCaptureDeviceInput * deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];      if (!deviceInput) {          if ([self.delegate respondsToSelector:@selector(DidFailToScanWithError:)]) {              [self.delegate DidFailToScanWithError:error];          }          return NO;      }      [self.captureSession addInput:deviceInput];      AVCaptureMetadataOutput * captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];      [self.captureSession addOutput:captureMetadataOutput];      dispatch_queue_t scanQRqueue;      scanQRqueue = dispatch_queue_create("scanQRqueue",DISPATCH_QUEUE_SERIAL);      [captureMetadataOutput setMetadataObjectsDelegate:self queue:scanQRqueue];      [captureMetadataOutput setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];      [self.vedioPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];      [self.vedioPreviewLayer setFrame:self.layer.bounds];      [self.layer addSublayer:self.vedioPreviewLayer];      [self.captureSession startRunning];      return YES;  }  -(void)stop{      [self.captureSession stopRunning];      self.isScaning = NO;      self.captureSession = nil;      [_vedioPreviewLayer removeFromSuperlayer];  }  #pragma mark - AVFoundation delegate method  -(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection  {      if (metadataObjects != nil && metadataObjects.count > 0) {          AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects firstObject];          if ([[metadataObject type] isEqualToString:AVMetadataObjectTypeQRCode]) {              NSString * scanResult = [metadataObject stringValue];              dispatch_async(dispatch_get_main_queue(), ^{                  if ([self.delegate respondsToSelector:@selector(DidGetScanWithResult:)]) {                      [self.delegate DidGetScanWithResult:scanResult];                  }              });          }      }  }    @end  

在使用的类中

//  //  ViewController.m  //  HwcAnimationExample  //  //  Created by huangwenchen on 15/1/6.  //  Copyright (c) 2015年 huangwenchen. All rights reserved.  //    #import "ViewController.h"  #import "HwcScanQRView.h"  @interface ViewController ()<HwcScanQRDelegate>//这里实现代理  @property (strong,nonatomic)UILabel * scanresultLabel;  @end    @implementation ViewController    - (void)viewDidLoad {      [super viewDidLoad];      HwcScanQRView * scanView = [[HwcScanQRView alloc] initWithFrame:CGRectMake(100,100,200, 200)];      scanView.delegate = self;//这一步必须的      [self.view addSubview:scanView];      self.scanresultLabel = [[UILabel alloc] initWithFrame:CGRectMake(100, 320, 200, 30)];      [self.view addSubview:self.scanresultLabel];      [scanView startScaning];//不要忘记开始扫描  }  //两个代理方法  -(void)DidGetScanWithResult:(NSString *)QRContent{      self.scanresultLabel.text = QRContent;  }  -(void)DidFailToScanWithError:(NSError *)error{      NSLog(@"%@",error.localizedDescription);  }    @end

来自： blog.csdn.net/hello_hwc