Weird issues when adding an object to a variable.

Question

Hey there! Today, i have started to work on a project, everything is working perfectly, but the inventory system.

I have gameobjects with an script attached, and another gameobject which is the player. The player has a script named "invManager" which contains all the code required for managing the inventory during the play. On the object i'm willing to pick up, i have another object attached, with an script which calls the invManager on the player to get himself added to the inventory list, then, the inventory does a quick check to see what slot is free, and places the pickable object there, but there seems to be a weird issue:

Whatever i do, the object gets attached to the slot 9 (the last one), but the real free slot is 1...

Here is the code on the pickable object (It does not destroys himself yet):

 using UnityEngine;
 using System.Collections;
 
 public class InputBlock : MonoBehaviour {
 
     public Color highColor;
     private Color startcolor;
     private bool showGUI = false;
     public GameObject mouseObject;
     public mouseManager mouseScript;
     public invManager invScript;
 
     void Start()
     {
         mouseScript = mouseObject.GetComponent<mouseManager>(); 
         invScript = mouseObject.GetComponent<invManager>();
     }
     void OnMouseEnter()
     {
         startcolor = renderer.material.color;
         renderer.material.color = highColor;
 
 
     }
     void OnMouseExit()
     {
         renderer.material.color = startcolor;
     }
 
     void OnMouseDown()  //TODO: Make a GUI (Not needed yet)
     {
         invScript.checkFreeSlots ();
         invScript.addBlock(this.gameObject);
 
 
     }
 }

And the invManager code:

 using UnityEngine;
 using System.Collections;
 
 public class invManager : MonoBehaviour {  //Script to manage inventory, and placement of blocks.
 
     //Slot definitions (Starts by 1)
     public GameObject slot1 = null;
     public GameObject slot2 = null;
     public GameObject slot3 = null;
     public GameObject slot4 = null;
     public GameObject slot5 = null;
     public GameObject slot6 = null;
     public GameObject slot7 = null;
     public GameObject slot8 = null;
     public GameObject slot9 = null;
     //End of slot definition
 
     public int freeSlot = 1; //Used to easily tell other scripts which slot to place stuff at
 
 
     void Start () {
         slot1 = null;
         slot2 = null;
         slot3 = null;
         slot4 = null;
         slot5 = null;
         slot6 = null;
         slot7 = null;
         slot8 = null;
         slot9 = null;
         print ("Inventory system initialized");
 
 
 
     }
     
 
     void Update () {
 checkFreeSlots();
         print (freeSlot);
     }
     public void checkFreeSlots(){  //Barebones function to check slots
         //The smaller slot is the chosen.
         if (slot1 == null) {
             freeSlot = 1;
             return;
         }
         if (slot2 == null) {
             freeSlot = 2;
             return;
         }
         if (slot3 == null) {
             freeSlot = 3;
             return;
         }
         if (slot4 == null) {
             freeSlot = 4;
             return;
         }
         if (slot5 == null) {
             freeSlot = 5;
             return;
         }
         if (slot6 == null) {
             freeSlot = 6;
             return;
         }
         if (slot7 == null) {
             freeSlot = 7;
             return;
         }
         if (slot8 == null) {
             freeSlot = 8;
             return;
         }
         if (slot9 == null) {
             freeSlot = 9;
             print ("Chosen 9");
             return;
         }
         
         
     }
     public void addBlock(GameObject blockObject)  //For some reason, always adds to slot 9
         {
         checkFreeSlots ();
         print (freeSlot);  //Debug (Always prints 9 for some reason...
         print ("[INV] Adding block...");
         if (freeSlot == 1) {
             slot1 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 2) {
             slot2 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 3) {
             slot3 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 4) {
             slot4 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 5) {
             slot5 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 6) {
             slot6 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 7) {
             slot7 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 8) {
             slot8 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
         if (freeSlot == 9) {
             slot9 = blockObject;
             print ("[INV] Success! Added Block to slot:"+freeSlot);
             return;
         }
             
 
     }
 
 
 }

The results of clicking on the pickable object: "Success! Added block to slot 9" And i'm specting: "Success! Added block to slot 1"

No idea why this happens... Thanks for your help!

Cheers!

Answer 1

I would suggest an iterative approach (makes your script shorter and more clear):

 using UnityEngine;
 using System.Collections;
 
 //Script to manage inventory, and placement of blocks.
 public class InvManager : MonoBehaviour
 {  
     public bool Full
     {
         get
         {
             return GetNextFreeSlot() < 0;
         }
     }
 
     //Slot definitions (Starts by 1)
     public GameObject[] Slots = new  GameObject[9];
 
 
     void Start()
     {        
         print("Inventory system initialized");
     }
 
     public int GetNextFreeSlot()
     {  
         //The smaller slot is the chosen.
         for (int i = 0; i < Slots.Length; i++)
         {
             GameObject go = Slots[i];
             if (go == null)
             {
                 return i;
             }
         }
 
         // Return -1 if no empty slot found
         return -1;
     }
 
     // Adds a block to the inventory is not full
     public void AddBlock(GameObject blockObject)  
     {
         if (!Full)
         {
             int slotIndex = GetNextFreeSlot();
 
             print("[INV] Adding block @ " + slotIndex);
 
             Slots[slotIndex] = blockObject;
         }
         else
         {
             print("[INV] Inventory is full...");
         }
     }
 }

And call it like this:

     void OnMouseDown() 
     {
         invScript.AddBlock(this.gameObject);
     }

But keep in mind that the instance 'invScript' should be globally available during runtime (singleton, static, ...).

I have also refactored your script to fit the common c# conventions.. ;)

Weird issues when adding an object to a variable.

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