修改Reachability检测2g、3g、4g网络

1.在networkStatusForFlags:方法里面找到以下地方，替换即可。

    if (flags & kSCNetworkReachabilityFlagsIsWWAN) {
        if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0) {
            CTTelephonyNetworkInfo *info = [[CTTelephonyNetworkInfo alloc] init];
            NSString *currentRadioAccessTechnology = info.currentRadioAccessTechnology;
            if (currentRadioAccessTechnology) {
                if ([currentRadioAccessTechnology isEqualToString:CTRadioAccessTechnologyLTE]) {
                    return kReachableVia4G;
                } else if ([currentRadioAccessTechnology isEqualToString:CTRadioAccessTechnologyEdge] || [currentRadioAccessTechnology isEqualToString:CTRadioAccessTechnologyGPRS]) {
                    return kReachableVia2G;
                } else {
                    return kReachableVia3G;
                }
            }
        }
        
        if ((flags & kSCNetworkReachabilityFlagsTransientConnection) == kSCNetworkReachabilityFlagsTransientConnection) {
            if((flags & kSCNetworkReachabilityFlagsConnectionRequired) == kSCNetworkReachabilityFlagsConnectionRequired) {
                return kReachableVia2G;
            }
            return kReachableVia3G;
        }
        return kReachableViaWWAN;
    }

2.iOS高级教程2:反射根据变量的引用获取变量名

- (NSString *)nameWithInstance:(id)instance {
    unsigned int ivarCount = 0;// 成员变量的数量
    Ivar *ivars = class_copyIvarList([self class], &ivarCount);// 获取这个类的 成员变量
    NSString *key = nil;
    for (int i=0; i<ivarCount; i++) {
        Ivar thisIvar = ivars[i];
        // 获取变量的类型，判断是否是对象
        NSString *type = [NSString stringWithUTF8String:ivar_getTypeEncoding(thisIvar)];
        if (![type hasPrefix:@"@"]) {
            continue;
        }
        if (object_getIvar(self, thisIvar) == instance) {// 获取实例对象的成员变量与传入实例对象的成员变量比较
            key = [NSString stringWithUTF8String:ivar_getName(thisIvar)];// 取得实例对象的成员变量名称
            break;
        }
    }
    free(ivars);
    return key;
}

#define varName(var) [NSString stringWithFormat:@"%s", #var]
NSString *abc = varName(abc);
NSLog(@"%@", abc);