observer iphone for view controllers

Question

Is there any way to to check the current navigation controller or the view controller currently visible in application delegate method.

I want to create an Observer in application delegate that observes the controller being pushed and pop from the stack so that i could display the required tab bar controller. Basically my app have more than one tab bar controllers.

Answer 1

Consider using NSNotification instances when your view controller stack changes its state. Google has lots of examples and explanations of this class (for example).

Answer 2

I blogged about this particular topic and give a code example: http://blog.corywiles.com/using-nsnotificationcenter-with-uinavigation