iPhone: How to make a proxy controller that can select different views+controllers

Question

I have an app with a TabBar.

One of the TabBar-connected views is actually variable:

Upon first opening of that view, it shall show a login dialog. If the user logs in, the login view is finished and the actual data view is shown.

Later, if the user goes back to this tab, the data view shall appear right away, so no more login dialog view.

Until now, I've solved this by directly manipulating the tab bar item's navigation controller's view controller array: Initially, it is set to show the login view. Once the user has logged in, the login controller is removed from the navigation controller and the actual data view is inserted instead.

I am not happy with this solution, though, as it causes problems once there are more than 5 tab items.

Hence, I wonder how I can avoid this navigation controller "patching" and instead have a new root controller for this tab that will then either invoke the login view or immediately show the data view.

Note: There are design reasons why the data view can't just pop up a modal view controller for the login. Therefore, I really like to provide something like a proxy controller that can direct the functionality to one of two other controllers of its choice.

How would I accomplish that?

Or are there other concepts I employ use here?

Answer 1

My suggestion would be to have two completely separate view controllers. Once login is complete, change the tab bar's view controller array by removing the login view controller and adding the content view controller. Something like this:

- (void) didLogin {
    UITabBarController *tabBarController = self.tabBarController;
    NSMutableArray *array = [NSMutableArray arrayWithARray:tabBarController.viewControllers];
    int idx = [array indexOfObject:self];
    UIViewController *contentViewController = //Create or get a chached copy of the content view controller
    //Optionally here you could copy the tab bar item rather than setting it up within the contentViewController.
    contentViewController.tabBarItem = self.tabBarItem;
    [array replaceObjectAtIndex:idx withObject:contentViewController];
    tabBarController.viewControllers = array;
    tabBarController.selectedViewController = contentViewController;
}

Edit:

If you're within the More view controller, it automatically detects if it's showing a navigation controller when choosing a tab normally. If you're doing it programmatically, I think you'd just have to do the same thing, but manually. Something like this:

- (void) didLogin {
    UITabBarController *tabBarController = self.tabBarController;
    NSMutableArray *array = [NSMutableArray arrayWithARray:tabBarController.viewControllers];
    if (array.count > 5 && [array indexOfObject:self] >= 5) {
        [tabBarController popToRootViewControllerAnimated:NO];
        [tabBarController.moreNavigationController pushViewController:contentViewController animated:NO];
        //Note: Not sure if this next line should be contentViewController or moreNavigationController.
        tabBarController.selectedViewController = contentViewController;
    } else {
        //Normal method above
    }
}