How do I integrate popToRootViewControllerAnimated with my tabs?

I am trying to make one of my tab buttons go to the root using popToRootViewControllerAnimated. My question is: where do I put this code for it to work? I have my tabs created through Interface Builder... do they have to be hard c开发者_StackOverflowoded for this to work?

Here is the code that I'm looking to use:

[self.navigationController popToRootViewControllerAnimated:YES];

New code in AppDelegate:

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
    if (viewController = HomeViewController) {
        [HomeViewController popToRootViewControllerAnimated:NO];
    }
}

Adam - I ended up ditching the subclass idea even though it worked, as there is a much easier method.

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
    if ([viewController isKindOfClass:[UINavigationController class]]) {
        [(UINavigationController*)viewController popToRootViewControllerAnimated:YES];
    }
}

This is the code required. I've uploaded this sample project to play around with. The main points are

• the UITabBarController delegate must be set to the App Delegate.
• the App Delegate must implement the <UITabBarControllerDelegate> protocol.
• the App Delegate must implement the code above.

The sample project also shows one way to selectively choose which navigation controllers this occurs with.

Yes this needs to be hardcoded.

If you're using a UITabBarController (I assume you probably are) you'll need to subclass it and override. This will try pop to the root view controller of each navigation controller on a tab. If the root view of a tab item is not a navigation item you will get an exception though.

@interface MyTabBarControllerSubClass : UITabBarController {
}
@end
@implementation MyTabBarControllerSubClass
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {
    [super tabBar:tabBar didSelectItem:item];
    [(UINavigationController*)self.selectedViewController popToRootViewControllerAnimated:YES];
}
@end

Don't forget to select your subclass in IB :-)

You could also make something a UITabBarControllerDelegate. Though it would probably be harder to implement.

Not sure why, but for me on Xcode 6 with Swift this solution did not work out. It seems even if didSelectViewController is called, popToRootViewControllerAnimated(false) is not.

I found that calling shouldSelectViewController instead works fine for me:

func tabBarController(tabBarController: UITabBarController, shouldSelectViewController viewController: UIViewController) -> Bool {
    if viewController.isKindOfClass(UINavigationController) {
        (viewController as UINavigationController).popToRootViewControllerAnimated(false)
        return true
    }
    return true
}

Not sure though if it is a good approach.