IOS: start a tabbarcontroller in a secondviewcontroller

Question

I want set a tabbar in my app and in my appDelegate I do this:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    UIViewController *viewController1 = [[[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil] autorelease];
    UIViewController *viewController2 = [[[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil] autorelease];
    [viewController2 viewDidLoad];
    UIViewController *viewController3 = [[[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil] autorelease];
    [viewController3 viewDidLoad];
    UIViewController *viewController4 = [[[FourthViewController alloc] initWithNibName:@"FourthViewController" bundle:nil] autorelease];
    [viewController4 viewDidLoad];
    self.tabBarController = [[[UITabBarController alloc] init] autorelease];
    self.tabBarController.viewControllers = @[viewController1, viewController2, viewController3, viewController4];

    self.viewController = [[[HomeViewController alloc] initWithNibName:@"HomeViewController" bundle:nil] autorelease];

    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

you can see that I want to start my app not immediately with tab bar, in fact I start my app with an HomeViewController

inside my HomeViewController i open viewController1 with:

FirstViewController *first = [[FirstViewController alloc]initWithNibName:@"FirstViewController" bundle:nil];
    [self presentViewController:first animated:YES completion:nil];
    [first release];

but in my firstviewcontroller I don't see my tabbar, why? (I state that the app work fine with tabbar if I start without homeviewcontroller)

Answer 1

You don't see tabbar because in HomeViewController you create new instance of FirstViewController and present it modally. You should create and present the whole UITabBarController inside HomeViewController:

AppDelegate:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    self.viewController = [[[HomeViewController alloc] initWithNibName:@"HomeViewController" bundle:nil] autorelease];

    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

inside HomeViewController:

FirstViewController *viewController1 = [[[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil] autorelease];
SecondViewController *viewController2 = [[[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil] autorelease];
ThirdViewController *viewController3 = [[[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil] autorelease];
FourthViewController *viewController4 = [[[FourthViewController alloc] initWithNibName:@"FourthViewController" bundle:nil] autorelease];

self.tabBarController = [[[UITabBarController alloc] init] autorelease];
self.tabBarController.viewControllers = @[viewController1, viewController2, viewController3, viewController4];

[self presentViewController:self.tabBarController animated:YES completion:nil];