ios根据文字内容生成二维码

- (UIImage *)createQRCodeFromString:(NSString *)string
{
NSData *stringData = [string dataUsingEncoding:NSUTF8StringEncoding];

CIFilter *QRFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// Set the message content and error-correction level
[QRFilter setValue:stringData forKey:@"inputMessage"];
[QRFilter setValue:@"M" forKey:@"inputCorrectionLevel"];

CGFloat scale = 5;
CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:QRFilter.outputImage fromRect:QRFilter.outputImage.extent];

//Scale the image usign CoreGraphics
CGFloat width = QRFilter.outputImage.extent.size.width * scale;
UIGraphicsBeginImageContext(CGSizeMake(width, width));
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, kCGInterpolationNone);
CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

//Cleaning up
UIGraphicsEndImageContext();
CGImageRelease(cgImage);

return image;
}