[ta-edu-course-survival-game] Chapter 2 — Composition vs Inheritance (3)

_Instructions.md

• Create InteractionHandler.cs
  • Let's try a compositional approach instead of hierarchical
  • We're going to compose our interactables with a list of handlers
  • Each handler will represent a specific behavior
• Convert Interactable to a non-abstract class
• Add a private InteractionHandler[] field called _handlers
• Add a for-loop for _handlers in Interact()
• Add a call to _handlers[i].Interact() to the for-loop
• Implement the Start() method
  • Now all we have to do is populate our handlers at the start of our game
• Initialize _handler using GetComponents<InteractionHandler>() in Start()
• Switch to Unity
• Update the Scene and verify the behavior

Interactable.cs

public class Interactable : MonoBehaviour
{
  private InteractionHandler[] _handlers;
  
  public void Awake()
  {
    _handlers = GetComponents<InteractionHandler>();
  }
  
  public void Interact()
  {
    for (var i = 0; i < _handlers.Length; i++)
    {
      _handlers[i].Interact()
    }
  }
}

InteractableAchievement.cs

public class InteractableAchievement : InteractionHandler
{
  public Achievements Achievements;
  public string Identifier;
  
  public void Interact()
  {
    Achievements.Track(Identifier);
  }
}

InteractableItem.cs

public class InteractableItem : InteractionHandler
{
  public Inventory Inventory;
  public string Item;
  
  public void Interact()
  {
    Inventory.Add(Item);
  }
}

InteractionHandler.cs

public abstract class InteractionHandler
{
  public abstract void Interact();
}