Change NavigationBar Text from Different ViewController
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I have a similar question posted prior to this one, but I now have a more clear question and more information along with code. I currently have a ViewController (SignUpViewController) with a UITextField and a UIButton. I also have another ViewController (ProfileViewController) that has a UINavigationBar. I want to be able to type a Username in the TextField in the SignUpViewController, tap the UIButton, then have the naviBar text in the ProfileViewController become set to the text in the SignUpViewController's TextField. Problem is, I can't access the UITextField from the ProfileViewController. I currently have an NSString in my AppDelegate called "titleString" and am trying to use that as some sort of a solution. Here is my code below if my question has completely thrown you off, as this is sort of difficult to explain over stack overflow:

SignUpViewController:

    - (IBAction)submitButton {
    
         ProfileViewController *profileVC = [[ProfileViewController alloc] initWithNibName:nil bundle:nil];
         [self presentViewController:profileVC animated:YES completion:nil];
    
         AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
         appDelegate.titleString = @"Profile";
    
         appDelegate.titleString = usernameTextField.text;
    
    }

    - (void)viewDidLoad {
    
         AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    
         [super viewDidLoad];
     }


ProfileViewController:

    - (void)viewDidLoad {
    
         AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
         self.title = appDelegate.titleString;
    
         [super viewDidLoad];
    }


it all works fine until I tap the submitButton in the SignUpViewController. What is going on here?

