使用系統自帶的框架完成掃描二維碼、條形碼，以及識別相冊中的二維碼

1、生成二維碼（使用coreImage.framework）

- (CIImage *)createQRForString:(NSString *)qrString {
    // Need to convert the string to a UTF-8 encoded NSData object
    NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];
    // Create the filter
    CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // Set the message content and error-correction level
    [qrFilter setValue:stringData forKey:@"inputMessage"];
    [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];
    // Send the image back
    return qrFilter.outputImage;
}

- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    // create a bitmap image that we'll draw into a bitmap context at the desired size;
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
    CGContextScaleCTM(bitmapRef, scale, scale);
    CGContextDrawImage(bitmapRef, extent, bitmapImage);
    // Create an image with the contents of our bitmap
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    // Cleanup
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    
    return [self imageBlackToTransparent:[UIImage imageWithCGImage:scaledImage] withRed:20.0f andGreen:70.0f andBlue:60.0f];
}

void ProviderReleaseData (void *info, const void *data, size_t size){
    free((void*)data);
}

而後用一句話調用

    [self.imageview setImage:[self createNonInterpolatedUIImageFormCIImage:[self createQRForString:@"今天"] withSize:size]];

就可生成二維碼。

2、掃描二維碼、條形碼（使用AVFoundation.framework）

1.導入#import <AVFoundation/AVFoundation.h>，遵循AVCaptureMetadataOutputObjectsDelegate協議
，並實現- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection這個方法。

2.聲明

@property (strong,nonatomic)AVCaptureDevice * device;  //設備
@property (strong,nonatomic)AVCaptureDeviceInput * input; //輸入流
@property (strong,nonatomic)AVCaptureMetadataOutput * output; //輸出流
@property (strong,nonatomic)AVCaptureSession * session;//捕捉會話
@property (strong,nonatomic)AVCaptureVideoPreviewLayer * preview; //預覽圖層

在viewDidLoad中實現

    _device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    _input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];

    _output = [[AVCaptureMetadataOutput alloc]init];

    [_output setRectOfInterest:CGRectMake((Height/3.0-10)/Height,0,(Height/3.0+20)/Height,1)];

    [_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

self.session = [[AVCaptureSession alloc]init];
    if ([_session canSetSessionPreset:AVCaptureSessionPreset1920x1080])
    {
        [_session setSessionPreset:AVCaptureSessionPreset1920x1080];
    }
    else if ([_session canSetSessionPreset:AVCaptureSessionPreset1280x720])
    {
        [_session setSessionPreset:AVCaptureSessionPreset1280x720];
    }
    else
    {
        [_session setSessionPreset:AVCaptureSessionPresetPhoto];
    }

 if ([_session canAddInput:self.input])
    {
        [_session addInput:self.input];
    }
    
    if ([_session canAddOutput:self.output])
    {
        [_session addOutput:self.output];
    }

// 條碼類型 AVMetadataObjectTypeQRCode
//    _output.metadataObjectTypes =@[AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code];

    _output.metadataObjectTypes =@[AVMetadataObjectTypeQRCode];
   
    _preview =[AVCaptureVideoPreviewLayer layerWithSession:self.session];
    _preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    _preview.frame =CGRectMake(0,0,Width,Height);
    [self.view.layer insertSublayer:self.preview atIndex:0];
   
    // 開啓
    [_session startRunning];

在代理方法中實現下面代碼

if ([metadataObjects count] >0)
    {

     ／／結束
        [_session stopRunning];
        //掃描到之後
        AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex:0];
        NSLog(@"%@",metadataObject.stringValue);
        [self playBeep];／／添加聲音
        self.textlabel.text=[NSString stringWithFormat:@"掃描信息：%@",metadataObject.stringValue];
        
    }

使用此方法能夠添加掃描到信息成功的聲音

- (void)playBeep{
    SystemSoundID soundID;
    NSString *path = [NSString stringWithFormat:@"/System/Library/Audio/UISounds/%@.%@",@"lock",@"caf"];
    AudioServicesCreateSystemSoundID((__bridge CFURLRef)[NSURL fileURLWithPath:path], &soundID);
    AudioServicesPlaySystemSound(soundID);
    AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
}

 

3、識別相冊中的二維碼（使用coreImage.framework）

1.不用導入文件，遵循UIImagePickerControllerDelegate,UINavigationControllerDelegate兩個協議

2.打開相冊

UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    imagePicker.delegate = self;
    [self presentViewController:imagePicker animated:YES completion:nil];

3.

//選中圖片的回調 -(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {     NSString *content = @"" ;     //取出選中的圖片     UIImage *pickImage = info[UIImagePickerControllerOriginalImage];     NSData *imageData = UIImagePNGRepresentation(pickImage);     CIImage *ciImage = [CIImage imageWithData:imageData];          //建立探測器     CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{CIDetectorAccuracy: CIDetectorAccuracyLow}];     NSArray *feature = [detector featuresInImage:ciImage];          //取出探測到的數據     for (CIQRCodeFeature *result in feature) {         content = result.messageString;     }     NSLog(@"%@",content);     [picker dismissViewControllerAnimated:YES completion:nil];     //進行處理(音效、網址分析、頁面跳轉等)        }