Category for a class that conforms to a protocol [duplicate]

问题

This question already has answers here:

Can a category implement a protocol in Objective C? (1 answer)

Making class conform to protocol with category for existing methods (2 answers)

Closed 6 years ago.

I'm trying to implement a category for a UIViewController and I want to be certain that the object conforms to a certain protocol. Something like this:

#import <UIKit/UIKit.h>

@interface UIViewController<MyProtocol> (Category)

@end

Is this possible?

回答1:

Swap category and protocol:

@interface UIViewController (Category) <MyProtocol>

来源：https://stackoverflow.com/questions/16682342/category-for-a-class-that-conforms-to-a-protocol