Question

My app requires an internet connection, so in the ApplicationDelegate, on applicationDidFinishLaunching I am running the following:

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

hostReach = [[Reachability reachabilityWithHostName: @"www.apple.com"] retain];
[hostReach startNotifer];
[self updateInterfaceWithReachability: hostReach];

But for some reason, this seems to be firing two times, since what gets logged is the following:

2010-02-04 14:25:48.004 myApp[201:207] Reachability Flag Status: -- ------- networkStatusForFlags
2010-02-04 14:25:48.240 myApp[201:207] STATUS: Access Not Available
2010-02-04 14:25:48.499 myApp[201:207] Reachability Flag Status: -- ------- networkStatusForFlags
2010-02-04 14:25:48.517 myApp[201:207] STATUS: Access Not Available

Which is good that it’s working, but I have an alert message to notify the user that there is no connection, and it pops up twice…

Why is the reachability notifier firing two times?

Answer 1

No idea why it’s popping up twice. Have you tried commenting out the call to startNotifier? It might do an initial check in the reachabilityWithHostName: method.

This might be a case where a workaround is the most appropriate fix, e.g.:

static bool userNotifiedOfReachability = NO;

...

- (void)updateInterfaceWithReachability:(Reachbility *)reachability {
    if (!userNotifiedOfReachability) {
        // Notify User

        ...

        userNotifiedOfReachability = YES;
    }
}

That would be appropriate for a “please try launching the app again later” message.