The view controller must be a child of some UINavigationController for the .title
property to take effect. If the UINavigationBar is simply a view, you need to push a navigation item containing the title, or modify the last navigation item:
UINavigationItem* item = [[UINavigationItem alloc] initWithTitle:@"title text"];
...
[bar pushNavigationItem:item animated:YES];
[item release];
or
bar.topItem.title = @"title text";