Question

I have my app that have some tab’s (tabbar).

In the first tab, there are UILabel’s, and on the third tab, there is methods, linked to buttons.

I want to change the value of the UILabel’s from the methods of the third button (launched trough those buttons)

Here is some code to illustrate all that :

FIRST PAGE (with UILabels)
@implementation FirstViewController

// definition des accesseurs
@synthesize details;
@synthesize recapitulatif;

...

And the method that will change the UILabels (SECOND PAGE WIHT BUTTONS – with the actual functions, don’t pay attention to those methods 😉 )

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [connection release];

    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    [responseData release];
    //NSString *responseString2 = [NSString stringWithFormat:@"%s%@%s", "[", responseString, "]"]; // Pour ajouter les [] si y'en a pas autour de tout le contenu JSON, et on doit utiliser responseString2 au lieu de responseString à la ligne ci-dessous
    NSArray *tableau = [responseString JSONValue];
    [responseString release];
    NSDictionary *dico = [tableau objectAtIndex:0];//NSDictionary *dico = [responseString JSONValue]; // sans [], on aurait fais ceci!

    // Si cette condition est vérifiée, c'est que le token est recu. On vas alors relancer une requete pour avoir les données.
    if ([dico objectForKey:@"token"]) {
        [ [MySingleton sharedMySingleton] setAuth:[dico objectForKey:@"token"] ];

        //affichage du message de confirmation de sauvegarde des mots de passe
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Login et Mot de passe" message:@"Votre login et votre mot de passe sont enregistrés." delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
        [alert show];
        [alert autorelease];
    }
}

Thanks for your reading / help !!!

Answer 1

Add an observer :

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(updateLabel:)
                                             name:@"LABELUPDATENOTIFICATION"
                                           object:nil];

in the class where the label exists i.e. 1st tab.

When the methods of the third button (launched trough those buttons) is invoked post a notification with updated text (NSString) object.

[[NSNotificationCenter defaultCenter] postNotificationName:@"LABELUPDATENOTIFICATION"
                                                    object:updatedStringLabelText] 

Implement the following notification method in the class having the labels.

- (void)updateLabel:(NSNotification*)notification
{
    NSString *updatedText = (NSString*)[notification object];
    [yourLabel setText:updatedText];
}