Check if an array index is empty

Question

I'm trying to find the first empty spot in my array, then add something there. The problem is this code:

 if (inventory[i] == null)
 {
     inventory[i] = item;
     print("Added item");
     return;
 }

Without the check, it will add an item to the array, but only in the 1st spot of 6, no matter what's there. Removing the return makes it use all 6 slots of course.

With the null check, it doesn't meet the condition. I think it's because of the class I'm using?

 using UnityEngine;
 using System.Collections;
 
 public class Inventory : MonoBehaviour {
     
     public InventoryItem[] inventory;
     
     [System.Serializable]
     public class InventoryItem
     {
         public GameObject worldObject;
         public Texture2D texRepresentation;
     }
     
     void Awake()
     {
         inventory = new InventoryItem[6];
     }
     
     public void AddItem(InventoryItem item)
     {
         for(int i = 0; i < inventory.Length; i++) 
         {
             if (inventory[i] == null)
             {
                 inventory[i] = item;
                 print("Added item");
                 return;
             }
         }    
         print("Inventory full");
     }
     
     public void NewItem(GameObject worldObject, Texture2D texRep)
     {
         var newItem = new InventoryItem();
         
         newItem.worldObject = worldObject;
         newItem.texRepresentation = texRep;
             
         AddItem(newItem);    
     }

 }

Answer 1

Solved it. It was much simpler than I thought!

 if (inventory[i].worldObject == null && inventory[i].texRepresentation == null)
 {
     inventory[i] = item;
     print("Added item");
     return;
 }

Full script:

 using UnityEngine;
 using System.Collections;
 
 public class Inventory : MonoBehaviour {
     
     public InventoryItem[] inventory;
     
     public bool displayInv = false;
     
     [System.Serializable]
     public class InventoryItem
     {
         public GameObject worldObject;
         public Texture2D texRepresentation;
     }
     
     void Awake()
     {
         inventory = new InventoryItem[6];
     }
     
     void Update()
     {
         if (Input.GetButtonDown("Inventory Key"))
         {
             if (!displayInv)
             {
                 print("Toggle Inv ON");
                 displayInv = true;
             }
             else
             {
                 print("Toggle Inv OFF");
                 displayInv = false;
             }
         }
     }
     
     public void AddItem(InventoryItem item)
     {
         for(int i = 0; i < inventory.Length; i++) 
         {
             if (inventory[i].worldObject == null || inventory[i].texRepresentation == null)
             {
                 inventory[i] = item;
                 print("Added item");
                 return;
             }
         }    
         print("Inventory full");
     }
     
     public void NewItem(GameObject worldObject, Texture2D texRep)
     {
         var newItem = new InventoryItem();
         
         newItem.worldObject = worldObject;
         newItem.texRepresentation = texRep;
             
         AddItem(newItem);    
     }
     
     void OnGUI()
     {
         if (displayInv)
         {
             GUI.Box(new Rect(Screen.width / 2, Screen.height / 2,250,250), "test");
         }
     }
     
 }

Check if an array index is empty

1 Reply

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions