Can not change text from a label in objective c - ios

Question

I am working on a app in objective c. Now i want a label to change text with the username's name after login. For some reason this don't work
Here is my code
#import "ViewController.h"
#interface ViewController ()
#property (strong, nonatomic) IBOutlet UITextField *userNameTextField;
#property (strong, nonatomic) IBOutlet UITextField *passwordTextField;
#property (strong, nonatomic) IBOutlet UILabel *labelWelkom;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)Login:(id)sender {
if ([_userNameTextField.text isEqualToString:#""] || [_passwordTextField.text isEqualToString:#""]) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"alert" message:#"Please Fill all the field" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
return;
}
NSString *strURL = [NSString stringWithFormat:#"http://localhost:8888/swift/login.php?userName=%#&password=%#",_userNameTextField.text, _passwordTextField.text];
NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:strURL]];
NSString *strResult = [[NSString alloc] initWithData:dataURL encoding:NSUTF8StringEncoding];
if ([strResult isEqualToString:#"1"])
{
NSString *username = _userNameTextField.text;
_labelWelkom.text = [NSString stringWithFormat:#"Hello %#", username];
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
UIViewController *vc = [sb instantiateViewControllerWithIdentifier:#"logedIn"];
vc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:vc animated:YES completion:NULL];
}
else if ([strResult isEqualToString:#"0"])
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"alert" message:#"Wrong username / password" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
return;
}
else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"alert" message:#"Server Error" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
return;
}
}
#end
Here is a image of my storyboard
In the left bottom you see my first page after login it loads the second page (upper right corner) in this page is the label that needs to change.

Answer 1

I think you set text of label before creating an instance. Try to assign after creating
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
UIViewController *vc = [sb instantiateViewControllerWithIdentifier:#"logedIn"];
vc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:vc animated:YES completion:NULL];
_labelWelkom.text = [NSString stringWithFormat:#"Hello %#", username];

Answer 2

I got some remarks :
.Your _labelWelkom is referring to your Login view controller. Where is the declaration of the loggedIn view label ?
.You defined an IBAction through Interface Builder. So why don't you use
(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
to present your 'loggedIn view' instead of instantiating and presenting this view programmatically here ?
UIStoryboard *sb = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
UIViewController *vc = [sb instantiateViewControllerWithIdentifier:#"logedIn"];
vc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:vc animated:YES completion:NULL];
If we preserve the present IB, let us remind that there is, as far as I know, two main ways to access your label in the second view :
Using IB :
Create another ViewController,i.e .h and .m files.
Link it to your 'Logged in' view controller in IB (through the Identity Inspector)
Link your label as an IBOutlet to your new view controller
In this first case, you should have a class in charge of getting your username after a successful login action. Using NSUserDefault is a way, among others to do this (check Stackoverflow Q&A to get more information).
Programmatically with keeping your IB as it is
Put a tag on your label in IB. Ex : 100.
In this second case, you can put text value to your UILabel within the first view controller implementation.
You can access it after your loggedIn view instantiation through :
UILabel* yourlabel =(UILabel*) [yourView viewWithTag: 100];
Look at this Q&A page :
How can I programmatically access UI elements in a NIB without 'wiring' them?
In this second case, you can put text value to your UILabel within the first view controller implementation.
I hope this will help you.