Object Refernce not set to an instance of an object error.

Unity Engine
1

Hello. I am extreamly new to coding, but as far as I can tell this script should work.

    public class HeartsGUI2 : MonoBehaviour {
       
       
        public GameObject Player22;
       
        public GUITexture image2;
        public Texture2D Image_1;
        public Texture2D Image_2;
        public Texture2D Image_3;
        public Texture2D Image_4;
        public Texture2D Image_5;
        public Texture2D Image_6;
        public int hp = 5;
       
        public bool isEnemy = true;
        void Awake()
        {
            Player22 = GameObject.Find("Player2");
        }
       
       
       
        void Update()
        {
         if (Player22.GetComponent<Health>().hp == 5) {
                image2.guiTexture.texture = Image_1;
            }
            if (Player22.GetComponent<Health>().hp == 4) {
                image2.guiTexture.texture = Image_2;
            }
           
            if (Player22.GetComponent<Health>().hp == 3) {
                image2.guiTexture.texture = Image_3;
            }
           
            if (Player22.GetComponent<Health>().hp == 2) {
                image2.guiTexture.texture = Image_4;
            }
           
            if (Player22.GetComponent<Health>().hp == 1) {
                image2.guiTexture.texture = Image_5;
            }
           
           
           
            if (Player22.GetComponent<Health>().hp <= 0) {
                image2.guiTexture.texture = Image_6;
            }
           
           
           
           
            {
               
               
               
            }
        }
    }

Basically the code is supposed to change the image displayed on a hearts GUI every time Player2 is shot to show how much health it has left. I made the same code referencing my Player1 and it works fine but when I copy pasted it over and renamed everything it no longer worked. Unity came up with an enormous amount of errors all saying the same thing. NullReferenceException: Object reference not set to an instance of an object
HeartsGUI2.Update () (at Assets/Scripts/HeartsGUI2.cs:28). Please help. Thank you.

2

Add

if(!player22)
{
Debug.LogError("Couldn't find Player 2");
}

inside your Awake function after you try to assign Player22. If this shows in the console as an error, the gameobject “Player2” is not in the scene

3

Ok I am an idiot for not noticing I accidentally named it Player 2 instead of Player2. The script still isn’t working though although it now shows no errors. I don’t understand why it doesn’t work here but does on Player1. I will post my first script. See if you can find what the difference is between the 2. Thank you.

using System.Collections;

public class HeartsGUI : MonoBehaviour {


    public GameObject Player1;

        public GUITexture image;
        public Texture2D Image_01;
        public Texture2D Image_02;
        public Texture2D Image_03;
        public Texture2D Image_04;
        public Texture2D Image_05;
        public Texture2D Image_06;
        public int hp = 5;
      
        public bool isEnemy = true;
    void Awake()
    {
        Player1 = GameObject.Find("Player");
    }
      


    void Update()
    {
        if (Player1.GetComponent<Health>().hp == 5) {
                        image.guiTexture.texture = Image_01;
                    }
        if (Player1.GetComponent<Health>().hp == 4) {
                        image.guiTexture.texture = Image_02;
                    }
                  
        if (Player1.GetComponent<Health>().hp == 3) {
                        image.guiTexture.texture = Image_03;
                    }
                  
        if (Player1.GetComponent<Health>().hp == 2) {
                        image.guiTexture.texture = Image_04;
                    }
                  
        if (Player1.GetComponent<Health>().hp == 1) {
                        image.guiTexture.texture = Image_05;
                    }
                  
                  
                  
        if (Player1.GetComponent<Health>().hp <= 0) {
                        image.guiTexture.texture = Image_06;
                }
                      
                      
                      
                      
                        {
                          
                          
                          
                        }
                    }
                }
4

Probably the Health component is not attached to your player2.
Just so you’re aware also, you can store a reference to your Health component on Awake() also. Which will clean your code up a bit.

using System.Collections;
public class HeartsGUI : MonoBehaviour {
    public GameObject Player1;
      private Health m_health;
        public GUITexture image;
        public Texture2D Image_01;
        public Texture2D Image_02;
        public Texture2D Image_03;
        public Texture2D Image_04;
        public Texture2D Image_05;
        public Texture2D Image_06;
        public int hp = 5;
 
        public bool isEnemy = true;
    void Awake()
    {
        Player1 = GameObject.Find("Player");
       m_health = Player1.GetComponent<Health>();
       if(!m_health)
       {
        Debug.LogError("Health component not attached");
       }
    }
 
    void Update()
    {
       if (m_health.hp == 5) {
                        image.guiTexture.texture = Image_01;
                    }
        if (m_health.hp == 4) {
                        image.guiTexture.texture = Image_02;
                    }
             
        if (m_health.hp == 3) {
                        image.guiTexture.texture = Image_03;
                    }
             
        if (m_health.hp == 2) {
                        image.guiTexture.texture = Image_04;
                    }
             
        if (m_health.hp == 1) {
                        image.guiTexture.texture = Image_05;
                    }
             
             
             
        if (m_health.hp <= 0) {
                        image.guiTexture.texture = Image_06;
                }
                 
                 
                 
                 
                        {
                     
                     
                     
                        }
                    }
                }

Also, are all of your Image_ the same texture? Are you just trying to draw a heart for every hp you have?

5

No. I have 6 images that I want to show on the GUI Texture depending on the health. My Health script is attached to player2 as well. I got the script to work now. Thank you for your help

6

How are you drawing them? Maybe they are positioned on top of each other so it looks like only 1 set is drawing.

Your code design is also not great. You should really only have 1 HeartsGUI component. Then your player class would reference this and feed it it’s own health. When I get back from work I may give you an example code.