interrupt or validate the action of a sender IBAction

Question

I try to control identifiers entered in a login form.

For the verification of access, no problem.

But how to stop or leave the action unfold from UIButton?

  - (IBAction)ConnexionBouton:(UIButton *)sender forEvent:(UIEvent *)event {
// ON RECUPERE LES IDENTIFIANTS DONNES LORS DE LA VALIDATION DU FORMULAIRE
NSString *emailString = _emailField.text;
NSString *passString = _PassField.text;
// ON APPEL LE METHODE SITUEE DANS LE FICHIER Json.h / .m AFIN DUTILISER LE PARSER JSON
ssJSON *AppelJSON = [[ssJSON alloc] init];
NSDictionary *resultatAppelJSON = [AppelJSON Dictionnaire];

NSDictionary *Joueurs = [resultatAppelJSON objectForKey:@"resultats"];
NSArray *Joueur = [Joueurs objectForKey:@"joueurs"];

for (NSDictionary *item in Joueur) {
    // RECHERCHE JOUEUR PAR LES IDENTIFIANTS DONNEES
    NSString *email_joueur = [item objectForKey:@"email"];
    NSString *PASS_joueur = [item objectForKey:@"PASS"];
    // ON CONTROLE SI LES IDENTIFIANTS DE CE JOUEUR CORRESPONDENT OU NON A CEUX TAPPES
    if ( email_joueur == emailString ) && ( PASS_joueur == passString )
    {

    }
    // DEBRIFING XCODE
    NSLog(@"%@", item);
}

}

Answer 1

If you want to stop executing the code in an IBAction method (which, remember, is just a method with a return type of void), then you can return; at any point.

Answer 2

include an else portion and leave the method with return when the ifconditions are not true.

if ( email_joueur == emailString ) && ( PASS_joueur == passString )
  {
     do the job;
  }

else {
     return;
     }

Answer 3

Try this

if ( [email_joueur isEqualToString:emailString] ) && ([ PASS_joueur isEqualToString:passString] )
      {
                //to do

     }
    else
    {
     //Wrong credentials 
    return;
    }

for checking string you have to sue isEqualString refer How to determine if strings are equal in Objective C?