调用ios系统生成二维码

第一步导入库 #import <CoreImage/CoreImage.h>

第二步复制粘贴

- (void)generateQrCode:(NSString *)str
{
    CIFilter * filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [filter setDefaults];
    NSData * data = [str dataUsingEncoding:NSUTF8StringEncoding];
    [filter setValue:data forKey:@"inputMessage"];
    //生成二维码
    CIImage * outImage = [filter outputImage];
    UIImage * image = [UIImage imageWithCIImage:outImage];
    //xib上的UIImageView
    self.codeImage.image = image;
}

第三部调用

[self generateQrCode:@"http://www.baidu.com"];

高级篇章

- (void)generateQrCode:(NSString *)str
{
    CIFilter * filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [filter setDefaults];
    
    if ([str isEqualToString:@""]) {
        return;
    }
    NSData * data = [str dataUsingEncoding:NSUTF8StringEncoding];
    [filter setValue:data forKey:@"inputMessage"];
    //生成二维码
    CIImage * outImage = [filter outputImage];
    
    self.codeImage.image = [self createNonInterpolatedUIImageFormCIImage:outImage withSize:self.codeImage.size.width];
    
//    UIImage * image = [UIImage imageWithCIImage:outImage];
//    //xib上的UIImageView
//    self.codeImage.image = image;
//    self.codeImage.layer.magnificationFilter = kCAFilterNearest;
}

- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    // 创建bitmap;
    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);
    // 保存bitmap到图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}