Unity Programming – Classes Inheritance (Ereditarietà) – Intermediate – CSharp

How does classes Inheritance work in Unity?

Create an Empty Object and attach the scripts.

FruitSalad.cs

public class FruitSalad : MonoBehaviour // estende MonoBehaviour, è la classe dalla quale ereditano tutti i componenti dei nostri giochi
{
    void Start()
    {
        //Let's illustrate inheritance with the 
        
	     //default constructors.
        
        Debug.Log("Creating the fruit"); 
        
        Fruit myFruit = new Fruit();  
        
        Debug.Log("Creating the apple"); 
        
        Apple myApple = new Apple();  

        //Call the methods of the Fruit class.

        //Now let's illustrate inheritance with the 
        //constructors that read in a string.
        Debug.Log("Creating the fruit");
        
        myFruit = new Fruit("yellow");// crea un'istanza della classe Fruit.cs
        
        Debug.Log("Creating the apple");
        
        myApple = new Apple("green"); // crea un'istanza della classe Apple.cs

        //Call the methods of the Fruit class.
        myFruit.SayHello(); // scrive: Hello. I am a fruit.
        
        myFruit.Chop(); // scrive: The yellow fruit has been chopped

        //Call the methods of the Apple class.
        //Notice how class Apple has access to all
        //of the public methods of class Fruit.
        myApple.SayHello(); // scrive: Hello. I am a fruit.
        
        myApple.Chop(); // scrive: The green fruit has been chopped
    
     }

}

[/charp]

Fruit.cs



using UnityEngine;
using System.Collections;

//This is the base class which is
//also known as the Parent class.
public class Fruit 
{
    public string color;

    //This is the first constructor for the Fruit class
    //and is not inherited by any derived classes.
    public Fruit() // deve esserci obbligatoriamente il costruttore che riceve 0 parametri
    {
        color = "orange";
        Debug.Log("1st Fruit Constructor Called");
    }

    //This is the second constructor for the Fruit class
    //and is not inherited by any derived classes.
    public Fruit(string newColor)
    {
        color = newColor;
        Debug.Log("2nd Fruit Constructor Called");
    }

    public void Chop()
    {
        Debug.Log("The " + color + " fruit has been chopped.");
    }

    public void SayHello()
    {
        Debug.Log("Hello, I am a fruit.");
    }
}

Apple.cs

using UnityEngine;
using System.Collections;

//This is the derived class whis is
//also know as the Child class.
public class Apple : Fruit // Apple estende Fruit 
{
    //This is the first constructor for the Apple class.
    //It calls the parent constructor immediately, even
    //before it runs.
    public Apple() // deve esserci obbligatoriamente il costruttore che riceve 0 parametri
    {
        //Notice how Apple has access to the public variable
        //color, which is a part of the parent Fruit class.
        color = "red"; // la proprietà color è in Fruit.cs
        Debug.Log("1st Apple Constructor Called");
    }

    //This is the second constructor for the Apple class.
    //It specifies which parent constructor will be called
    //using the "base" keyword.
    public Apple(string newColor) : base(newColor)
    {
        //Notice how this constructor doesn't set the color
        //since the base constructor sets the color that
        //is passed as an argument.
        Debug.Log("2nd Apple Constructor Called");
    }
}

On console:

– Creating the fruit
– 1st Fruit Constructor Called

– Creating the apple
– 1st Fruit Constructor Called
– 1st Apple Constructor Called

– Creating the fruit
– 2nd Fruit Constructor Called

– Creating the apple
– 2nd Fruit Constructor Called
– 2nd Apple Constructor Called

– Hello, I am a fruit
– The yellow fruit has been chopped

– Hello, I am a fruit
– The green fruit has been chopped

For italian people:

1. Fruit myFruit = new Fruit(); -> public Fruit(), il costruttore senza parametri

2. Apple myApple = new Apple(); -> public Fruit() poi public Apple()

3. myFruit = new Fruit(“yellow”); -> public Fruit(string newColor)

4. myApple = new Apple(“green”); -> -> public Fruit(string newColor) poi public Apple(string newColor) : base(newColor) specifica la chiamata al costruttore di Fruit.cs tramite la keyword : base(newColor) – estende newColor

5. Fruit.cs scrive Debug.Log(“Hello, I am a fruit.”); e Debug.Log(“The ” + color + ” fruit has been chopped.”);