UIKit: Is it possible to make a category for UIKeyboard?

I want to make a category on UIKeyboard, but I get the error, "Cannot find interface declaration for UIKeyboard`. But, when I try to give it an interface declaration, I get a warning that it's already defined by开发者_如何转开发 UIKit. What should I do?

There is no public definition for UIKeyboard, hence you cannot add a category to it because adding a category to a class requires access to it's interface header.