iOS长按选择

确实，其实就是一个长按手势 + 图片二维码识别，原生SDK从8.0开始支持

/**
 *  从照片中直接识别二维码
 *  @param qrCodeImage 带二维码的图片
 *  @param myQRCode    二维码包含的内容
 */
+ (void)readQRCodeFromImage:(UIImage *)qrCodeImage myQRCode:(void(^)(NSString *qrString,NSError *error))myQRCode;{
    
    UIImage * srcImage = qrCodeImage;
    if (nil == srcImage) {
        myQRCode(nil,[NSError errorWithDomain:@"未传入图片" code:0 userInfo:nil]);
        return;
    }
    
    CIContext *context = [CIContext contextWithOptions:nil];
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:context options:@{CIDetectorAccuracy:CIDetectorAccuracyHigh}];
    CIImage *image = [CIImage imageWithCGImage:srcImage.CGImage];
    NSArray *features = [detector featuresInImage:image];
    if (features.count) {
        CIQRCodeFeature *feature = [features firstObject];
        
        NSString *result = feature.messageString;
        
        myQRCode(result,nil);
    }
    else{
        myQRCode(nil,[NSError errorWithDomain:@"未能识别出二维码" code:0 userInfo:nil]);
        return;
    }
    
}