Show UINavigationBar From AppDelegate

I have an app that allows the user to hide/show the UINavigationBar on the main screen. The navigation bar can be toggled whenever the user touches the screen twice with two fingers, but if the user closes out of the app with the navigation bar gone, and they open it back up again and forgot what they were doing, the user is "left in the dark" on what to do next. It's not obvious that the navigation bar is hidden, and it's especially not obvious on how to get it back. So my question is how can I use AppDelegate.m's

- (void)applicationDidBecomeActive:(UIApplication *)application

method to regain visibility of the navigation bar. I've tried just about everything I could thing of from class methods to passing parameters.