Warning For UITextFieldDelegate

I am following a tutorial within the IOS 6 Cookbook Fourth Edition on how to hide the keyboard when a user clicks Done. Unfortunately I am getting a warning that I do not understand b/c I'm a java guy pretending to understand this Objective C stuff. I took a screenshot of exactly what I am looking at so that everyone can see exactly where the warning is. Thanks.

enter image description here

Solution

in the .h file declare this class to implement the protocol by using

@interface IT315ViewController : UIViewController <UITextFieldDelegate>