iOS生成二维码，原生和ZXing

1.系统自带#import 框架生成二维码

/**
 *  根据字符串生成二维码 CIImage 对象
 *
 *  @param urlString 需要生成二维码的字符串
 *
 *  @return 生成的二维码
 */
- (CIImage *)creatQRcodeWithUrlstring:(NSString *)urlString{
    
    // 1.实例化二维码滤镜
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 2.恢复滤镜的默认属性 (因为滤镜有可能保存上一次的属性)
    [filter setDefaults];
    // 3.将字符串转换成NSdata
    NSData *data  = [urlString dataUsingEncoding:NSUTF8StringEncoding];
    // 4.通过KVO设置滤镜, 传入data, 将来滤镜就知道要通过传入的数据生成二维码
    [filter setValue:data forKey:@"inputMessage"];
    // 5.生成二维码
    CIImage *outputImage = [filter outputImage];
    return outputImage;
}

系统自带识别图片中的二维码

/**
 *  读取图片中的二维码
 *
 *  @param image 图片
 *
 *  @return 图片中的二维码数据集合 CIQRCodeFeature对象
 */
+ (NSArray *)readQRCodeFromImage:(UIImage *)image{
   
    // 创建一个CIImage对象
    CIImage *ciImage = [[CIImage alloc] initWithCGImage:image.CGImage options:nil];
    CIContext *context = [CIContext contextWithOptions:@{kCIContextUseSoftwareRenderer : @(YES)}]; // 软件渲染
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:context options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh}];// 二维码识别
    // 注意这里的CIDetectorTypeQRCode
    NSArray *features = [detector featuresInImage:ciImage];
    NSLog(@"features = %@",features); // 识别后的结果集
    for (CIQRCodeFeature *feature in features) {
        NSLog(@"msg = %@",feature.messageString); // 打印二维码中的信息
    }
    return features;
}

2.ZXing生成二维码。需要导入第三方#import "ZXingObjC.h"

/**
 *  根据字符串生成二维码 UIImage 对象
 *
 *  @param str 需要生成二维码的字符串
 *  @param size 生成的大小
 *  @param format 二维码选 kBarcodeFormatQRCode
 *  @return 生成的二维码
 */
+ (UIImage*)createCodeWithString:(NSString*)str
                            size:(CGSize)size
                      CodeFomart:(ZXBarcodeFormat)format
{
    ZXMultiFormatWriter *writer = [[ZXMultiFormatWriter alloc] init];
    ZXBitMatrix *result = [writer encode:str format:format width:size.width height:size.width error:nil];
    ZXImage *image = [ZXImage imageWithMatrix:result];
    return [UIImage imageWithCGImage:image.cgimage];
}

ZXing识别图片中的二维码

CGImageRef imageRef = image.CGImage;
    ZXCGImageLuminanceSource * source = [[ZXCGImageLuminanceSource alloc] initWithCGImage:imageRef];
    ZXBinaryBitmap * bitmap = [ZXBinaryBitmap binaryBitmapWithBinarizer:[ZXHybridBinarizer binarizerWithSource:source]];
    NSError * error = nil;
    ZXDecodeHints * hints = [ZXDecodeHints hints];
    ZXMultiFormatReader * reader = [ZXMultiFormatReader reader];
    ZXResult * result = [reader decode:bitmap hints:hints error:&error];
    if (result) {
        NSString * contents = result.text;
    }