Replace a UIViewController in the UINavigationController hierarchy

Question

I have an iPhone app which uses a standard implementation of UINavigationController for the app navigation.

I am trying to figure out a way to replace a view controller in the hierarchy. In other words, my app loads into a rootViewController and when the user presses a button, the app pushes to firstViewController. Then the user pushes another button to navigate the app to secondViewController. Again the use navigates down to another view controller, thirdViewController. However, I want the BackButton of the thirdViewController to pop back to firstViewController.

Essentially, when the user pushes to thirdViewController, I would like it to replace secondViewController in the navigation hierarchy.

Is this possible? I know it is using Three20, but I'm not in this case. Nevertheless, if it's possible in Three20, then it certainly should be using straight SDK calls. Does anyone have any thoughts?

Cheers, Brett

Answer 1

Pretty Simple, when about to push the thirdViewController instead of doing a simple pushViewController do this:

NSArray * viewControllers = [self.navigationController viewControllers]; NSArray * newViewControllers = [NSArray arrayWithObjects:[viewControllers objectAtIndex:0], [viewControllers objectAtIndex:1], thirdController,nil]; [self.navigationController setViewControllers:newViewControllers]; 

where [viewControllers objectAtIndex:0] and [viewControllers objectAtIndex:1] are your rootViewController and your FirstViewController.

Answer 2

NSMutableArray *viewController = [NSMutableArray arrayWithArray:[navController viewControllers]]; [viewController replaceObjectAtIndex:1 withObject:replacementController]; [navController setViewControllers:viewController]; 

See the UINavigationController class reference for more information.