TabBatController with viewControllers - viewcontroller

Question

In my tabBarController-based app, I have four tabs - tabA, tabB, tabC and tabD. The user will be able to jump between the tabs.
Now to my question:
- tabA, tabB and tabD have single viewControllers
- tabC though has 3 viewControllers - vc1, vc2 and vc3
I am running into issue where the app remembers which viewController the user was in last, and when the user taps tabC, the control goes to the last view controller that the user was in. For example, let's say the following is the sequence:
User taps tabA : view controller for tabA is shown
User taps tabD : view controller for tabD is shown
User taps tabC : view controller vc1 is shown. On tapping some action, the user is taken to vc3
User taps tabB : view controller for tabB is shown
User taps tabC : the vc3 is shown - instead I'd like to show vc1
So far, I have tried the following in vc1 of tabC, but the control does not come to vc1 at all:
- (void) viewWillAppear:(BOOL)animated {
[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:0] animated:YES];
}
How can I tell tabC to always load vc1?
Regards - thanks in advance....
Sam.

Answer 1

Your call to vc1 of tabC likely isn't getting called - viewWillAppear: only gets called when the view will appear on the display.
You might want to look at this function:
- (void)tabBarController:(UITabBarController *)tabBarController
didSelectViewController:(UIViewController *)viewController
(Link to Apple Developer docs)
and this function:
- (NSArray *)popToRootViewControllerAnimated:(BOOL)animated
(Link to Apple Developer docs)
If you implement this in your tabBarController delegate, you can act when the user selects tabC, ie:
- (void)tabBarController:(UITabBarController *)tabBarController
didSelectViewController:(UIViewController *)viewController
{
if (viewController == \* tabC view controller */) {
[tabCViewController.navigationController popToRootViewController:YES];
}
}

Answer 2

#dvorak: Thanks for the answer - and sorry to drag on....
I know what I am writing is not an answer - but wanted to show the code that I am working with.
I am not having luck w/ the suggestion. I made the AppDelegate the TabBarControllerDelegate. The callback function gets called - however, using the following code, I am not able to popToRootViewController:
- (void)tabBarController:(UITabBarController *)tbController didSelectViewController:(UIViewController *)viewController {
NSLog(#"ViewController is <%#>", viewController.tabBarItem.title);
if ([viewController.tabBarItem.title isEqualToString:#"tabC"]) {
NSArray *tmp = [viewController.navigationController.tabBarController viewControllers];
[viewController.navigationController popToRootViewControllerAnimated:YES];
}
}
I collected the all ViewControllers in tmp variable , in a hope to see 3 ViewControllers in the array, after visiting all three VCs of tabC. From tabC->vc3, I hit the tabB, and then hit tabC for my exercise. The tmp array had zero elements in the debugger.