Disable button when no internet connection

How do I disable a button when there is no connection to a netw开发者_StackOverflowork / internet in iOS?

---

Check out the reachability code from Apple.

http://developer.apple.com/library/ios/#samplecode/Reachability/Introduction/Intro.html

and use it like this:

Reachability *reachabilityInstance = [[Reachability reachabilityForInternetConnection] retain];
[reachabilityInstance startNotifier];
NetworkStatus networkStatus = [reachabilityInstance currentReachabilityStatus];
BOOL connected = (networkStatus==ReachableViaWiFi || networkStatus==ReachableViaWWAN);

---

You can simply hide a button whenever you need to

[button setHidden:YES];