popping a view controller in different tab

Question

UPDATE This code appears to do what I want, but I am curious if this is a bad tactic now.

func tabBarController(tabBarController: UITabBarController, didSelectViewController viewController: UIViewController) {
    print("pop view controller from tab bar")

    if tabBarController.selectedIndex == 2 {
        print("appdel detected index 2 tab")
        let navCont = viewController as! UINavigationController
        navCont.popToRootViewControllerAnimated(true)
    }
}

ORIGINAL QUESTION: I have some code that will delete data another tab refers to. I want to make sure that when this code executes in [Edit Record VC] that it will force tab to pop back to the root view, even though the code executes on its own tab:

[ ---------------TAB BAR CONTROLLER ------------------ ]
  TAB 0              TAB 1         TAB 2           TAB 3
     |                 |              |              |
     |                 |              |              |
  [NAV CONTR 0]  [NAV CONTR 1]  [NAV CONTR 2]  [NAV CONTR 3]
                       |              |        
                       |              |  
                   [Table VC]      [Map VC]
                       \              /
                        \            /
                         \          /
                       [View Record VC]
                               |
                               |
                       [Edit Record VC]

In the above drawing, when I delete a record in [Edit Record VC], I want to pop Nav Controller 1 and Nav Controller 2 to the very first VC. How can I do this? I have tried every way I can think of and the code just isn't working.

The reason I want to do this is because if NAV CONTR 2 navigates to [Edit Record VC] and deletes the record, [View Record VC] will still be referencing that record, causing it to point to a deleted object. When I try to open the NAV CONTR 2 tab after deletion, it'll cause a crash

Answer 1

Multiple objects reacting to an event sounds like a job for NSNotification.

Make NAV CONTR 1 and NAV CONTR 2 instances of a navigation controller subclass that listens for a notification (resetToFirstController or something). Make posting that notification part of the delete logic.

When each controller receives the notification it pops to its root...or whichever "safe" controller you choose.