Objective-c Protocol

The protocol in OC is similar to the excuse of Java

The Protocol is special.ProgramDesign Patterns are used to declare methods implemented by other classes. Protocols are useful in the following scenarios:

1. There must be other class implementation methods.

2. Excuses for declaring unknown classes

3. Communication between two classes

Basic Features of the Protocol

The Protocol can be implemented by any class

The Protocol itself is not a class. It defines an interface that can be implemented by other classes.

Protocols can also be used for categories

Protocol declaration and implementation

@ Required: indicates the method that must be implemented forcibly.

@ Optional: indicates the method that can be implemented selectively.

// Protocol declaration @ protocol firstprotocol <nsobject> // <nsobject> indicates the base protocol. You can leave @ required-(void) requiredmethod; @ optional-(void) optionalmethod; @ end // use this Protocol @ interface person: nsobject <firstprotocol, secondprotocol> @ end @ implementation person-(void) requiredmethod {}