ios - 生成二维码

Question

我需要使用 objective-c 生成二维码。是否已经有可用的库/框架？谢谢

Answer 1

我使用这个简单的代码在我的一个项目中对 QRCode 进行编码。您可以使用:

//
//  QRCodeGeneratorViewController.h
//  
//
//  Created by Jhoney Lopes on 28/09/14.
//  Copyright (c) 2014 Jhoney Lopes. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface QRCodeGeneratorViewController : UIViewController

@end

执行.m

//
//  QRCodeGeneratorViewController.m
// 
//
//  Created by Jhoney Lopes on 28/09/14.
//  Copyright (c) 2014 Jhoney Lopes. All rights reserved.
//

#import "QRCodeGeneratorViewController.h"

@interface QRCodeGeneratorViewController ()
@property (strong, nonatomic) IBOutlet UIImageView *qrImageView;
@end

@implementation QRCodeGeneratorViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    [self generateTheQRCodeImageFromDataBaseInfo:@"TEXT-WHAT-YOU-WANT-TO-CONVERT-IN-QRCODE"];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - QR Code Generator

- (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:@"H" forKey:@"inputCorrectionLevel"];

    // Send the image back
    return qrFilter.outputImage;
}

- (UIImage *)createNonInterpolatedUIImageFromCIImage:(CIImage *)image withScale:(CGFloat)scale
{
    // Render the CIImage into a CGImage
    CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:image fromRect:image.extent];

    // Now we'll rescale using CoreGraphics
    UIGraphicsBeginImageContext(CGSizeMake(image.extent.size.width * scale, image.extent.size.width * scale));
    CGContextRef context = UIGraphicsGetCurrentContext();
    // We don't want to interpolate (since we've got a pixel-correct image)
    CGContextSetInterpolationQuality(context, kCGInterpolationNone);
    CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage);
    // Get the image out
    UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
    // Tidy up
    UIGraphicsEndImageContext();
    CGImageRelease(cgImage);
    return scaledImage;
}

- (void)generateTheQRCodeImageFromDataBaseInfo:(NSString *)jsonString {

    // Get the string
    NSString *stringToEncode = jsonString;

    // Generate the image
    CIImage *qrCode = [self createQRForString:stringToEncode];

    // Convert to an UIImage
    UIImage *qrCodeImg = [self createNonInterpolatedUIImageFromCIImage:qrCode withScale:2*[[UIScreen mainScreen] scale]];

    // And push the image on to the screen
    self.qrImageView.image = qrCodeImg;
}