Q:

popToViewController and memory management

I have three view controllers pushed in navigationcontroller on the third one i used the statement
[self.navigationController popToViewController:(Main_View*) mainViewObj animated:YES];
It takes me directly to my specified controller say first.  I have done some coding to remove objects from an NSMutableDictionary in viewWillDisappear method in all view controllers, i tried debugging using break points but it never comes to viewWillDisappear, it takes me directly to Main_View.  Should i be worried about removing objects from dictionary or releasing it? 

A:

The viewWillDisappear: method is not called for the other view controllers because they have already disappeared when you were pushing view controllers on top of them.  So basically, viewWillDisappear: was already called for them at an earlier point.  It wouldn't make sense to call it again, because they weren't visible in the first place.