View Controller being sent a message even though it has been deallocated

Question

I am not sure if something has changed in the iPhone SDK 3.0 but I am getting the strangest error. I have a view controller hierarchy where I switch between view controllers

Answer 1

This is a good reason to set the ToolbarController = nil after releasing it. It's safe to send messages to nil, but not to addresses of deallocated objects. In this case your sending a message to an address of an object that doesn't exit, which is causing a crash.

It's a waste of time to check for the ToolbarController != nil before sending the message, because if it's nil, than you can send the message safely. if it is not nil and valid, then it will return YES or NO. But if it's a pointer to deallocated memory (such as you seem to have here) it's going to crash anyway.