UiViewController - Pop doesn't pop

I'm displaying UIControllerView subclass when a button is pressed from a another UIViewController like this:

- (IBAction)openNextLevelViewController
{
    NSLog(@"openNextlevelViewController");

    [self.navigationController pushViewController:nextLevelViewController animated:YES];

}

And the app will return from that view on a button push which trigger this method:

-(IBAction) returnToStart {

    NSLog(@"returnToStart method called");
    [self.navigationController popViewControllerAnimated:YES];

}

The problem is that the displayed view not getting destroyed/deallocated on the pop. As a result, when it gets pushed, it's not executing the viewDidLoad, which initiates some variables. This may be causing a related problem where, the second time through, when the user presses the return button, the "pop" no longer causes a return to the 开发者_如何学Pythonprevious controller.

What's the best way to deal with this? I could move the initialization code to the "willAppear" method, but it seems as if that could be called almost randomly.

---

Well, its not getting released because nextLevelViewController is still being retained somewhere else. Most likely in your nextLevelViewController variable.

- (IBAction)openNextLevelViewController
{
    NSLog(@"openNextlevelViewController");
    // assuming you have nib already set up
    UIViewController *nextLevelViewController = [[NextLevelViewController alloc] init]; 
    // RETAIN COUNT = 1

    // navigationController retains your controller
    [self.navigationController pushViewController:nextLevelViewController animated:YES]; 
    // RETAIN COUNT = 2

    // Don't need it any more let navigation controller handle it.
    [nextLevelViewController release]
    // RETAIN COUNT = 1 (by NavigationController)
}

Further On

-(IBAction) returnToStart {
    [self.navigationController popViewControllerAnimated:YES];
    // RETAIN COUNT = 0, dealloc will be called on your viewController, make sure to release all your retained objects.
}

Now when your controller gets popped, it SHOULD get released (shouldn't have been retained anywhere else). And next time you call openNExtLevelViewController, it'll be initializing a new instance of your viewController anyway.

I'm a fan of releasing viewController when it is no longer needed (displayed), instead of holding it in memory. Let navigationController and TabBarController handle viewControllers whenever possible.