how to add naviagationController to tabBar Controller programatically?
<p>In AppDelegate.m i am writing following code for navigationbar.</p>

<pre><code>MaterialsListViewController *materials = [[MaterialsListViewController alloc]initWithNibName:@"MaterialsListView" bundle:nil];
    UINavigationController *navigation = [[UINavigationController alloc]initWithRootViewController:materials];
</code></pre>

<p>In the same AppDelegate.m i am writing follwing code for tabbar.   </p>

<pre><code>UIViewController *viewController1, *viewController2;
viewController1 = [[[MaterialsListViewController alloc] initWithNibName:@"MaterialsList" bundle:nil] autorelease];
viewController2 = [[[RecentMaterialsListViewController alloc] initWithNibName:@"RecentMaterialsList" bundle:nil] autorelease];
self.tabBarController = [[[UITabBarController alloc] init] autorelease];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];
NSArray *items = self.tabBarController.tabBar.items;
UITabBarItem *item1 = [items objectAtIndex:0];
[item1 setTitle:@"Materials"];
UITabBarItem *item2 = [items objectAtIndex:1];
[item2 setTitle:@"Recent"];
self.window.rootViewController = self.tabBarController;
</code></pre>

<p>How to add NavigationBar to the tabbar?</p>
