Question

I can’t belice I am asking this, but im very crazy with this variable stuff.

I want to save a username information. I load them at the load of my view. After this I will get the information when I click on a button.

Here is my code:

@interface SelfViewController : UIViewController
{
    NSString *usernameString;
}



- (void)viewDidLoad
{
     usernameString = @"test";
}



- (IBAction)goToProfileButtonPressed:(id)sender
{
    NSLog(@"%@", usernameString); //CRASH BAD EXEC

}

What did I wrong????

Answer 1

Change your .h file to:

@interface SelfViewController : UIViewController {
    NSString *usernameString;
}

@property (retain, nonatomic) NSString *usernameString;

Then in your .m file:

@synthesize usernameString;

- (void)viewDidLoad {
     self.usernameString = @"test";
}

- (IBAction)goToProfileButtonPressed:(id)sender {
    NSLog(@"%@", self.usernameString); // "self." can be omitted, but it is best practice not to
}

- (void)dealloc {
    [usernameString release];

    [super dealloc];
}

The problem is that you assign usernameString to an autoreleased string object. By the time the button is pressed, usernameString has been released and has become garbage memory. By retaining it (and subsequently releasing it in -dealloc to avoid a leak) you know that it will not be prematurely released.