Question

I have programatically created a TabBarController with views etc. Now i want to show this TabBarController on Button Press. How do i do that? Currently i am presenting it modally but it doesn’t work – throws sigtrap errors.

This is my code for the TabBarController

@implementation TabBarViewController

- (void) loadView
{
    HomeViewController * homeViewController = [[HomeViewController alloc]initWithNibName:@"HomeViewController" bundle:nil];

    UITabBarController *tabBarController = [[UITabBarController alloc] init];
tabBarController.view.frame = CGRectMake(0, 0, 320, 460);

   // Set each tab to show an appropriate view controller
   [tabBarController setViewControllers:[NSArray arrayWithObjects:homeViewController, homeViewController, nil]];
   [self.view addSubview:tabBarController.view];
   [homeViewController release];
   [tabBarController release];
}

This is my code for accessing this tabBarController from a Button Press event from my mainViewController –

 - (IBAction)quickBrowse:(UIButton *)sender
{
    TabBarViewController * tabBarController = [[TabBarViewController alloc]init];
    [self presentModalViewController:tabBarController animated:YES];
    [tabBarController release];
}

Answer 1

You should only override the method loadView if you are not using IB and if you want to create yours view manually. And when you do that you must assign your root view to the view property of UIViewController.

I believe in your case you don’t need to override this method, you can use the viewDidLoad method to create your UITabBarController and store it in a variable, so when the event gets called all you need to do is pass the variable to the method presentModalViewController:animated:

Your final code would look like this:

- (void) viewDidLoad
{
    [super viewDidLoad];

    HomeViewController * homeViewController = [[HomeViewController alloc]initWithNibName:@"HomeViewController" bundle:nil];

    // you can't pass the same view controller to more than one position in UITabBarController
    HomeViewController * homeViewController2 = [[HomeViewController alloc]initWithNibName:@"HomeViewController" bundle:nil];

    // local variable
    self.modalTabBarController = [[UITabBarController alloc] init];

   // Set each tab to show an appropriate view controller
   [self.modalTabBarController setViewControllers:[NSArray arrayWithObjects:homeViewController, homeViewController2, nil]];
}

- (void)viewDidUnload
{
    self.modalTabBarController = nil;
    [super viewDidUnload];
}

 - (IBAction)quickBrowse:(UIButton *)sender
{
    [self presentModalViewController:self.modalTabBarController animated:YES];
}