Question

In an iOS app, I’m defining my own protocol to use the delegate pattern among my custom view controllers. Which files should #import which other files? In other words, there are four files involved in my case:

• MainViewController.h: Declares a protocol and a view controller than implements the protocol
• MainViewController.m: Implements the protocol methods
• SecondaryViewController.h: Declares a delegate instance variable and property of type id <Protocol> (with a forward declaration of Protocol)
• SecondaryViewController.m: Uses the protocol method on the delegate

Which files should #import which others? I’d think the forward declaration in the second view controller’s header would be enough, but I get compile warnings/errors unless the second header or implementation imports the main header.

Answer 1

SecondaryViewController.m should import the header as it uses the protocol methods.