Wie bekomme ich den Benutzernamen, wenn die Benutzersitzung geöffnet ist? Wenn jemand die Lösung kennt, helfen Sie mir bitte. Danke im Voraus.

 - (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];
            }];
        }
    }