如何在wifi源丢失连接时检测到网络可达性的丢失？

Question

我正在努力获得真实的互联网连接状态.我已经使用了Apple的Reachability但它只给了我wifi连接的状态,即没有覆盖设备通过wifi连接(到路由器或热点)的情况,但wifi路由器或热点本身没有连接到互联网.通过从wifi路由器拉入互联网输入电缆可以重现这种情况.ReachableViaWiFi两个reachabilityForInternetConnection和的可达性通知程序返回ReachabilityWithHostName.我对这个问题非常感兴趣.我通过它尝试了它,NSURLConnection但是电池耗尽过多而且个人我不喜欢那种继续发出URL请求的解决方案,尽管在后台线程中.

这是我正在使用的代码(由SO老师提供,但不记得确切的链接)

 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkNetworkStatus:) name:kReachabilityChangedNotification object:nil];

    internetReachable = [[Reachability reachabilityForInternetConnection] retain];
    [internetReachable startNotifier];

    // check if a pathway to a random host exists
    hostReachable = [[Reachability reachabilityWithHostName: @"www.google.com"] retain];
    [hostReachable startNotifier];

然后在观察者方法中:

 - (void) checkNetworkStatus:(NSNotification *)notice{

    // called after network status changes

    NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];
    switch (internetStatus)

    {
        case NotReachable:
        {
            NSLog(@"The internet is down.");
            self.isInternetReachable = NO;

            break;

        }
        case ReachableViaWiFi:
        {
            NSLog(@"The internet is working via WIFI.");
            self.isInternetReachable = YES;

            break;

        }
        case ReachableViaWWAN:
        {
            NSLog(@"The internet is working via WWAN.");
            self.isInternetReachable = YES;

            break;

        }
    }
    NetworkStatus hostStatus = [hostReachable currentReachabilityStatus];
    switch (hostStatus)

    {
        case NotReachable:
        {
            NSLog(@"A gateway to the host server is down.");
            self.isHostReachable = NO;

            break;

        }
        case ReachableViaWiFi:
        {
            NSLog(@"A gateway to the host server is working via WIFI.");
            self.isHostReachable = YES;

            break;

        }
        case ReachableViaWWAN:
        {
            NSLog(@"A gateway to the host server is working via WWAN.");
            self.isHostReachable = YES;

            break;

        }
}
}

Answer 1

根据Reachability,它不仅检查wifi,还检查WWAN/3G并且没有互联网接入,为什么你认为除了WIFI之外它不检查？

 typedef enum {

    NotReachable = 0,

    ReachableViaWiFi,

    ReachableViaWWAN

} NetworkStatus;

如果你想检查特定主机的可达性,那么你可以像这样自己设置主机

Reachability *hostReach = [Reachability reachabilityWithHostName: @"www.google.com"];

NetworkStatus netStatus = [hostReach currentReachabilityStatus];

 switch (netStatus)
    {
        case ReachableViaWWAN:
        {
            NSLog(@"WWAN/3G");
            break;
        }
        case ReachableViaWiFi:
        {
            NSLog(@"WIFI");
            break;
        }
        case NotReachable:
        { 
            NSLog(@"NO Internet");
            break;
        }
}