來源
讀取主要用到CoreImage 不過要強(qiáng)調(diào)的是讀取二維碼的功能只有在iOS8之后才支持，我們需要在相冊中調(diào)用一個(gè)二維碼，將其讀取，代碼如下

#pragma mark-> 我的相冊
-(void)myAlbum{
    
    NSLog(@"我的相冊");
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){
        //1.初始化相冊拾取器
        UIImagePickerController *controller = [[UIImagePickerController alloc] init];
        //2.設(shè)置代理
        controller.delegate = self;
        //3.設(shè)置資源：
        /**
         UIImagePickerControllerSourceTypePhotoLibrary,相冊
         UIImagePickerControllerSourceTypeCamera,相機(jī)
         UIImagePickerControllerSourceTypeSavedPhotosAlbum,照片庫
         */
        controller.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
        //4.隨便給他一個(gè)轉(zhuǎn)場動(dòng)畫
        controller.modalTransitionStyle=UIModalTransitionStyleFlipHorizontal;
        [self presentViewController:controller animated:YES completion:NULL];
        
    }else{
        
        UIAlertView * alert = [[UIAlertView alloc]initWithTitle:@"提示" message:@"設(shè)備不支持訪問相冊，請?jiān)谠O(shè)置->隱私->照片中進(jìn)行設(shè)置！" delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];
        [alert show];
    }
    
}

完成相冊代理， 我們在代理中添加讀取二維碼方法

#pragma mark-> imagePickerController delegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    //1.獲取選擇的圖片
    UIImage *image = info[UIImagePickerControllerOriginalImage];
    //2.初始化一個(gè)監(jiān)測器
    CIDetector*detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{ CIDetectorAccuracy : CIDetectorAccuracyHigh }];
    
    [picker dismissViewControllerAnimated:YES completion:^{
        //監(jiān)測到的結(jié)果數(shù)組
        NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:image.CGImage]];
        if (features.count >=1) {
            /**結(jié)果對象 */
            CIQRCodeFeature *feature = [features objectAtIndex:0];
            NSString *scannedResult = feature.messageString;
            UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"掃描結(jié)果" message:scannedResult delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];
            [alertView show];
          
        }
        else{
            UIAlertView * alertView = [[UIAlertView alloc]initWithTitle:@"提示" message:@"該圖片沒有包含一個(gè)二維碼！" delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];
            [alertView show];
            
        }
        
  
    }];
    
    
}