Checking for network connectivity iOS

Creating a Reachability listener

Apple’s Reachability class periodically checks the network status and alerts observers to changes.

Reachability *internetReachability = [Reachability reachabilityForInternetConnection];
[internetReachability startNotifier];

Add observer to network changes

Reachability uses NSNotification messages to alert observers when the network state has changed. Your class will need to become an observer.

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

Elsewhere in your class, implement method signature

- (void) reachabilityChanged:(NSNotification *)note {
    //code which reacts to network changes}

Alert when network becomes unavailable

- (void)reachabilityChanged:(NSNotification *)note {
    Reachability* reachability = [note object];
    NetworkStatus netStatus = [reachability currentReachabilityStatus];if (netStatus == NotReachable) {
        NSLog(@"Network unavailable");   }}

Alert when connection becomes a WIFI or cellular network

- (void)reachabilityChanged:(NSNotification *)note {
    Reachability* reachability = [note object];
    NetworkStatus netStatus = [reachability currentReachabilityStatus];switch (netStatus) {
        case NotReachable:NSLog(@"Network unavailable");break;
        case ReachableViaWWAN:NSLog(@"Network is cellular");break;
        case ReachableViaWiFi:NSLog(@"Network is WIFI");break; 
}}