1、二維碼尺寸必須是59*59及以上，否則微信內(nèi)長按識別不了二維碼，其他手機(jī)掃二維碼可能會掃不出來

代碼:

+ (UIImage *)generateQRCodeWithString:(NSString *)string size:(CGFloat)size {

? ? if(!string || string.length==0) {

? ? ? ? returnUIImage.new;

? ? }

? ? CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

? ? //過濾器恢復(fù)默認(rèn)

? ? [filtersetDefaults];

? ? //給過濾器添加數(shù)據(jù)<字符串長度893>

? ? NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion: NO];

? ? [filtersetValue:dataforKey:@"inputMessage"];

? ? // 注： 這里如果設(shè)置H的時(shí)間 二維碼太小可能會造成信息不全 無法掃描

? ? [filtersetValue:@"M" forKey:@"inputCorrectionLevel"];

? ? //獲取二維碼過濾器生成二維碼

? ? CIImage*image = [filteroutputImage];

? ? UIImage *img = [self createNonInterpolatedUIImageFromCIImage:[image imageByApplyingTransform:CGAffineTransformMakeScale(YYScreenScale(), YYScreenScale())] WithSize:size];

? ? returnimg;

}

+ (UIImage *)createNonInterpolatedUIImageFromCIImage:(CIImage *)image WithSize:(CGFloat)size {

? ? CGRect extent = CGRectIntegral(image.extent);

? ? CGFloatscale =MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

? ? //創(chuàng)建bitmap

? ? size_twidth =CGRectGetWidth(extent)*scale;

? ? size_theight =CGRectGetHeight(extent)*scale;

? ? CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();

? ? CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);

? ? CIContext *context = [CIContext contextWithOptions:nil];

? ? CGImageRefbitmapImage = [contextcreateCGImage:imagefromRect:extent];

? ? CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);

? ? CGContextScaleCTM(bitmapRef, scale, scale);

? ? CGContextDrawImage(bitmapRef, extent, bitmapImage);

? ? //保存圖片

? ? CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);

//? ? UIImage *newImage = [UIImage imageWithCGImage:scaledImage];

? ? UIImage *newImage = [UIImage imageWithCGImage:scaledImage scale:YYScreenScale() orientation:UIImageOrientationUp];

? ? CGContextRelease(bitmapRef);

? ? CGImageRelease(bitmapImage);

? ? CGColorSpaceRelease(cs);

? ? CGImageRelease(scaledImage);

? ? returnnewImage;

}