Refreshing tabbarcontroller views on logout in iPhone application - uinavigationcontroller

Question

We have a tab bar + navigation control project. We have created a tab bar through interface builder and added all tab items to the tab bar controller through through interface builder.
Our application has a login screen which we are showing as a modal form at the beginning. Once the user is authenticated, the login screen is dismissed (using dismissModalScreen) and the MainWindow is shown. This is all working fine.
Now, we have a logout option clicking on which we should show the login screen back. We are able to show that as well. But the issue is once the user is authenticated again, we want all the screens to be loaded freshly. Currently, all screens maintain their state and retain previous data.
What we have tried to do is:
[AppDelegate tabBarController release];
AppDelegate.tabBarController = nil;
We have tried releasing the tabBarController and setting it to nil. But once the view is shown, we are not able to select any of the tabs and the view is blank.
What we need is:
Once the user logs in second time, how to release and reload each viewcontroller which are part of tabbar.
Your help will be greatly appreciated.

Answer 1

We have found a way out. What we are doing now is, once the user logs back in, we are releasing the view controllers and recreating them and setting it back to the uitabbar.
NSMutableArray *arrControllers = [[AppDelegate.tabBarController.viewControllers] mutablecopy];
[arrControllers removeAtIndex:3];
[arrControllers removeAtIndex:2];
----Create New Controllers
UIViewController viewController2 = [[UIViewController alloc] initWithNibName:#"viewController2" bundle:nil] autorelease];
UIViewController viewController3 = [[UIViewController alloc] initWithNibName:#"viewController3" bundle:nil] autorelease];
--Create Nav controller
UINavigationController navViewController2 = [[[UINavigationController alloc] initWithRootViewController:viewController2 ] autorelease];
UINavigationController navViewController3 = [[[UINavigationController alloc] initWithRootViewController:viewController3 ] autorelease];
[arrControllers addObject:navViewController2];
[arrControllers addObject:navViewController3];
[AppDelegate.tabViewController setViewControllers:arrControllers];
It is working fine after this change.
Only problem we faced was if we release all objects from the array, we get a carsh. Is it because, when you release allObjects, the first controller which is the RootViewController is getting released?
Thanks