Loading specific ViewControllers on tabBarController

I am having problems loading specific ViewControllers on the tabBarController. This is what my project looks like:

T开发者_Python百科abAppDelegate.m
--------------------

#import "TabAppDelegate.h"
#import "ViewControllerA.h"
#import "ViewControllerB.h"
//etc #import up to F 

- (void)applicationDidFinishLaunching:(UIApplication *)application 
{
    tabBarController = [[UITabBarController alloc] init];

    UIViewController *viewController1 = [[[ViewControllerA alloc] initWithNibName:@"ViewControllerA" bundle:nil] autorelease];
    UIViewController *viewController2 = [[[ViewControllerA alloc] initWithNibName:@"ViewControllerB" bundle:nil] autorelease];
    tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];

    [window addSubview:tabBarController.view];
    [self.window makeKeyAndVisible];
    return YES;
}


Interface builder
------------------
Tab Bar Controller
    ViewControllerA
    ViewControllerB
    ViewControllerC
    ViewControllerD
    ViewControllerE
    ViewControllerF

Each ViewController is linked to a class bearing the same name.

As you can see from the diagram above, in Interface Builder I've got a Tab Bar Controller inside which there are lots of View Controllers. In applicationDidFinishLaunching I have written some (clearly wrong!) code with the purpose of only displaying controller A and B within the Tab Controller at launch. However the program crashes immediately with the following error message:

Thread 1: Program received signal: "SIGABRT"

If in applicationDidFinishLaunching I omit the first 4 lines of code (i.e., I don't try to load ONLY ViewControllerA and ViewControllerB) the program launches perfectly, but with ALL the ViewControllers.

Any idea on what I am doing wrong? Thanks!

---

tabBarController = [[UITabBarController alloc] init]; isn't needed if its already linked to your UITabBarController in the Interface Builder:

Try this:

- (void)applicationDidFinishLaunching:(UIApplication *)application 
{
    UIViewController *viewController1 = [[[ViewControllerA alloc] initWithNibName:@"ViewControllerA" bundle:nil] autorelease];
    UIViewController *viewController2 = [[[ViewControllerA alloc] initWithNibName:@"ViewControllerB" bundle:nil] autorelease];
    tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];

    [window addSubview:tabBarController.view];
    [self.window makeKeyAndVisible];
    return YES;
}