UINavigationController always loads table view with same data

I have a navigation controller based app. My views consist of two tableviews laid out like this:

Category
    Item within category

Basically i allow users to create the categories using the + button on the navigation bar. Then they select a category, and can then press the + button again to create items in that category.

My problem is if i create a category, and add some items, then go back up and choose a different category, the same items from the first category are displayed.

This is what i use to create my item controllers in didSelectRow:

if (detailViewController==nil) 
     detailViewController = [[ItemViewController alloc] init];

 detailViewController.category = [[APP_DELEGATE listsArray] objectAtIndex:indexPath.row];
 [self.navigationController pushViewController:detailViewController animated:YES];

From viewDidLoad in ItemViewController:

items = [[NSMutableArray alloc] initWithCapacity:30];

How can i stop the same items being displayed for each?

Thanks

EDIT:

Code that populates items:

- (void)addNameController:(AddName *)addNameController didAddName:(NSString *)name {

if (name) {
    NSLog(@"%@", name);
    [items addObject:name];
    [self.ta开发者_Python百科bleView reloadData];
}
[self dismissModalViewControllerAnimated:YES];
}

Move the initialization of the items array to viewDidAppear in ItemViewController and call reloadData. The viewDidLoad is only getting called the first time ItemViewController is alloc'd and pushed.