1. 导入头文件
   #import <ifaddrs.h>
#import <net/if.h>
2. 关键代码

+ (BOOL)isWIFIEnable {
    NSCountedSet *countedSet = [NSCountedSet new];
    struct ifaddrs *interfaces;
    if (!getifaddrs(&interfaces)) {
        for (struct ifaddrs *interface = interfaces; interface; interface = interface->ifa_next) {
            if ((interface->ifa_flags & IFF_UP) == IFF_UP) {
                NSString *ifa_name = [NSString stringWithUTF8String:interface->ifa_name];
                [countedSet addObject:ifa_name];
            }
        }
    }
    freeifaddrs(interfaces);
    // 网上有人判断的是awdl0
    BOOL open = [countedSet countForObject:@"en0"] > 1 ? YES : NO;
    YJPrint(@"wifi open status: %@", open ? @"open" : @"unopen");
    return open;
}

网上有一种方法判断的是awdl0, 但是我测试发现在iOS12/iOS10上面,wifi开启/关闭的状态下awdl0出现的次数都是2,无法判断.反而en0在wifi关闭时出现0次,wifi开启时出现2次,可以用来判断wifi开启状态.