在iOS中连接或断开wifi时如何获取通知？

Question

I'm trying to get iOS to notify my app when a wifi connection is either established or disconnected.

I tried the following code in iPhone and iPad with iOS 4.3.5 and 5.1:

- (void)startWifiNotifier {
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(statusUpdated:) 
                                                 name:kReachabilityChangedNotification 
                                               object:nil];

    Reachability *wifi = [Reachability reachabilityForLocalWiFi];
    [wifi startNotifier];
    NSLog(@"Wifi status: %i", [wifi currentReachabilityStatus]);
    NSLog(@"Notifier started");
}

- (void)statusUpdated:(NSNotification *)notice {
    NetworkStatus s = [[notice object] currentReachabilityStatus];
    if(s == NotReachable) {
        NSLog(@"Wifi disconnected");
    } else {
        NSLog(@"Wifi connection established");
    }
}

The problem is that my callback "statusUpdated" never gets called. I know this SHOULD work as is, but I tried both getting in and out of the wifi range (and therefore getting connected and disconnected to it) and turning on and off the wifi router to force disconnection and my callback is never called.

I also tried this:

@private
    Reachability *wifi;
...

- (void) startTimerLog {
   wifi = [Reachability reachabilityForLocalWiFi];
   [self timerLog];
}

- (void) timerLog {
    NSLog(@"Reachability: %i", [wifi currentReachabilityStatus]);
    [self performSelector:@selector(timerLog) withObject:nil afterDelay:0.5];    
}

and tested it under the same scenarios and it works fine. However that's not the approach I need, I rather need notifications to invoke my callback.

Is there anything else I have to do to make the notifier work?

Answer 1

Use this library http://huytd.github.io/datatify/ it's very easy to use and to customize. The setCallback method will help you detect when the connection changed