Question

I’m confused with this delegate message. I have a navigation controller in a PopupViewController. When I push a new viewController I wan’t to know what is the viewController that its being currently displayed, before the new one gets pushed…

I’ve tried getting navigationController.topViewController & navigationController.visibleViewContrller, but both of them always equal to the viewController that its going to be pushed… It looks like I’m receiving the message after the view was pushed

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
   UIViewController *currentViewController = navigationController.topViewController;
    if(currentViewController == viewController){
      /// THIS IF STATEMENT IS ALWAYS TRUE 
    }
}

Has anyone stumbled upon anything similar?

Answer 1

Did some digging in the UINavigationController Class Reference and it looks like you can use the viewControllers property of the UINavigationController class.

The root view controller (bottom of the navigation stack) is at index 0 with the with the back view controller (the one that just got covered) at index n-2 and the topViewController property being at index n-1 where n is the number of view controllers in the array.

As of iOS 7 and Xcode 5.x, you can now send the firstObject message to the array returned by the viewControllers property to get the root viewcontroller. Similarly, the topViewController property can be accessed by sending the lastObject message to the array returned by the viewControllers property.