Interface is another cornerstone concept in the Object-oriented Programming. They are not classes so that they can't have their own instances.
Features of interface:
- A class can implement more than one interfaces
- All methods and property (or member variables) must be implemented
- An interface can inherit from another interface
- Interface is a great way of organizing the code and classes that allows different classes to share similar functions
- Interface can only have abstract methods and properties, we can understand the interface is a completely abstract class
- Interface can contain either properties or methods. Same as the other programming languages such as Swift, Java is a bit different
Example of interface:
By convention, interfaces starts with a capital I followed by a name, also the name is preferred to use something like -able to describe its function.
using UnityEngine;
using System.Collections;
//This is a basic interface with a single required method.
public interface IDestroyable {
void Destroy();
}
//This is a generic interface where T is a placeholder
//for a data type that will be provided by the
//implementing class.
public interface IPurchasable<T> {
void Purchase(T price);
}
// interface on property
public interface ICar {
int Year { get; set; }
}
When a class implements a interface, it must implement all the methods of that interface:
using UnityEngine;
using System.Collections;
public class Car: MonoBehaviour, IPurchasable<float> , IDestroyable, ICar {
//The required method of the IKillable interface
public void Destroy() {
//Do something fun
}
//The required method of the IPurchasable interface
public void Purchase(float price) {
//Do something fun
}
// automatically implemented
public int Year { get; set; }
}