iOS生成二维码例子

//1. 实例化二维码滤镜

CIFilter*filter = [CIFilterfilterWithName:@"CIQRCodeGenerator"];

//2. 恢复滤镜的默认属性

[filtersetDefaults];

//3. 将字符串转换成NSData

NSData*data = [strdataUsingEncoding:NSUTF8StringEncoding];

//4. 通过KVO设置滤镜inputMessage数据

[filtersetValue:dataforKey:@"inputMessage"];

//5. 获得滤镜输出的图像

CIImage*outputImage= [filteroutputImage];

//6. 将CIImage转换成UIImage，并放大显示

return[UIImageimageWithCIImage:outputImagescale:20.0orientation:UIImageOrientationUp];