title: How to get user info from Facebook SDK in iOS?
body: <p>How to get user name when user session is open.I tried the session login sample from Facebook sdk samples. if any one knows the solution please help me out.
  Thanks in advance. </p>
  
  <pre><code> - (IBAction)buttonClickHandler:(id)sender {
          // get the app delegate so that we can access the session property
          SLAppDelegate *appDelegate = [[UIApplication sharedApplication]delegate];
  
          // this button's job is to flip-flop the session from open to closed
          if (appDelegate.session.isOpen) {
              // if a user logs out explicitly, we delete any cached token information, and next
              // time they run the applicaiton they will be presented with log in UX again; most
              // users will simply close the app or switch away, without logging out; this will
              // cause the implicit cached-token login to occur on next launch of the application
     //hear i need to fetch user name ?
  
  
              [appDelegate.session closeAndClearTokenInformation];
  
          } else {
              if (appDelegate.session.state != FBSessionStateCreated) {
                  // Create a new, logged out session.
                  appDelegate.session = [[FBSession alloc] init];
              }
  
              // if the session isn't open, let's open it now and present the login UX to the user
              [appDelegate.session openWithCompletionHandler:^(FBSession *session,
                                                               FBSessionState status,
                                                               NSError *error) {
                  // and here we make sure to update our UX according to the new session state
                  [self updateView];
              }];
          }
      }
  </code></pre>