ios如何生成二维码

//1.创建滤镜
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

//2.恢复默认
[filter setDefaults];

//3.给滤镜添加数据
NSString *dataString = @"http://www.xxx.com/theDesertIslandOutOfTheWorld/";
//  NSString *dataString = @"世俗孤岛";
//将数据转换成NSData类型
NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];
//通过KVC设置滤镜的二维码输入信息
[filter setValue:data forKey:@"inputMessage"];

//4.获取输出的二维码图片（CIImage类型）
CIImage *outImage = [filter outputImage];
//将CIImage类型的图片装换成UIImage类型的图片
UIImage *image = [UIImage imageWithCIImage:outImage];

//5.显示二维码图片
self.imageView.image = image;