Protocols and Categories
Explore protocols for defining communication contracts and categories for adding methods to existing classes without subclassing.
Extending Behavior: Intro
Welcome to this lesson on Objective-C Protocols and Categories! These are powerful features that allow you to extend the functionality of your classes in flexible ways.
We'll explore how protocols define contracts for communication between objects and how categories let you add methods to existing classes without needing to subclass them.
Protocols: The Communication Contract
Think of an Objective-C protocol as a blueprint or a contract. It declares a list of methods that other classes can choose to implement.
- A class that 'adopts' a protocol promises to implement its required methods.
- This is crucial for establishing communication patterns, like the popular delegate pattern.
- Protocols are similar to interfaces in languages like Java or C#.
All lessons in this course
- Classes, Objects, and Methods
- Properties and Instance Variables
- Protocols and Categories
- Inheritance and Method Overriding