Objective C - How can I create an interface?

Question

I need to be able to create an interface like you create in C# to enforce a group of classes to implement certain methods. Is this possible in objective c?

Answer 1

In the Objective-C world, interfaces are called "Protocols"

According to Apple,

Protocols declare methods that can be implemented by any class. Protocols are useful in at least three situations:

To declare methods that others are expected to implement
To declare the interface to an object while concealing its class
To capture similarities among classes that are not hierarchically related

So, to declare a protocol you can:

@protocol SomeClassProtocol
- (void) do:(int) number something:(id) sender;
- (void) somethingElse;
@end

To implement a protocol , you do:

@interface MyClass : NSObject 
@end

Check out this link for the official documentation.