Problem with accesing variables from another class

Unity Engine
,
1

Hi, I am making a 2D game and I wanted to access variables from class Buttons in class ValuesOfJanusz and vice versa. I did it writing:

public Buttons buttons = mainCamera.GetComponent<Buttons>();

And:

public ValuesOfJanusz voj = mainCamera.GetComponent<ValuesOfJanusz>();

But when I’m trying to load the game, I get this classic error:
Object reference not set to an instance of an object (in ValuesOfJanusz line 7, Buttons line 10)
I’ve tried many ways to solve the problem but I still have this problem.
What will you suggest?

I’m getting you full code:
Buttons:

using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.UI;

public class Buttons : MonoBehaviour {
    public static GameObject mainCamera;
    //załączenie klasy ValuesOfJanusz
    public ValuesOfJanusz voj = mainCamera.GetComponent<ValuesOfJanusz>();
    //zmienne pasków
    public bool ate;
    public bool slept;
    public bool healed;
    //zmienne sterująca czasem
    public bool done;
    public int hour;
    public Text time;
    //lodówka
    public GameObject fridgeInside;
    public GameObject exitFridge;
    public GameObject food;
    public Text textOfFood;
    public int countOfFood;
    bool fridgeOpened;
    //stół
    public GameObject gazeta;
    public GameObject ii;

    //dymek Janusza
    public GameObject dymek;

    //////////////////////////////
    void Start () {
        done = false;
        hour = 8;
        ate = false;
        healed = false;
        slept = false;
        fridgeInside.SetActive (false);
        exitFridge.SetActive (false);
        food.SetActive (false);
        countOfFood = 3;
        fridgeOpened = false;
        gazeta.SetActive (false);
        ii.SetActive (false);
        dymek.SetActive (false);
    }
   
    ////////////////////////////////
    void Update () {
        if (done) {
            ++hour;
            time.text = hour.ToString() + ":00";
            done = false;
            if (hour == 23) {
                hour = -1;
            }
        }
        if(fridgeOpened){
        textOfFood.text = countOfFood.ToString ();
        }
    }
    //obsługa ekranu tytułowego
    public void TitleButton(){
        SceneManager.LoadScene ("House");
    }
    //otwieranie lodówki
    public void FridgeClicked(){
        fridgeInside.SetActive (true);
        exitFridge.SetActive (true);
        food.SetActive (true);
        food.SetActive (true);
        fridgeOpened = true;
    }
    //spanie
    public void BedClicked(){
        if (voj.sleep < 10) {
            done = true;
            voj.sleep++;
        }
    }
    //jedzenie
    public void FoodClicked(){
        if (voj.hunger < 10) {
            ate = true;
            countOfFood--;
            voj.hunger++;
        }
    }
    //zamykanie lodówki
    public void ExitFridge(){
        fridgeInside.SetActive (false);
        exitFridge.SetActive (false);
        food.SetActive (false);
        fridgeOpened = false;
    }
    //klikanie stołu
    public void TableClicked(){
        gazeta.SetActive (true);
        ii.SetActive (true);
    }
    //czytanie gazety
    public void GazetaClicked(){
        done = true;
        gazeta.SetActive (false);
        ii.SetActive (false);
    }
    //robienie ii
    public void doii(){
        done = true;
        gazeta.SetActive (false);
        ii.SetActive (false);
    }
}

ValuesOfJanusz:

using UnityEngine;

public class ValuesOfJanusz : MonoBehaviour {

    public static GameObject mainCamera;

    public Buttons buttons = mainCamera.GetComponent<Buttons>();

    bool JanuszAction;
    public int hp;
    public int hunger;
    public int sleep;
    public int lvl;
    public int exp;
    void Start () {
        hp = 10;
        hunger = 10;
        sleep = 10;
        lvl = 0;
        exp = 0;
    }
   

    void Update () {

        //obsługa lvl
        if (JanuszAction) {
            exp++; JanuszAction = false;
        }
        if (exp == 100) {
            lvl++;
            exp = 0;
        }

        //obsługa pasków hp, hunger i sleep
        if (buttons.ate) {
            if (hunger < 10) {
                hunger++;
                buttons.ate = false;
            }
        }
        if (buttons.healed) {
            if (hp < 10) {
                hp++;
                buttons.healed = false;
            }
        }
        if (buttons.slept) {
            if (sleep < 10) {
                sleep++;
                buttons.slept = false;
            }
        }
        /////////////////////
    }
}
2

you can’t do this:

public ValuesOfJanusz voj = mainCamera.GetComponent<ValuesOfJanusz>();

You must move this to the Start or Awake methods

public ValuesOfJanusz voj;
void Start(){
    voj = mainCamera.GetComponent<ValuesOfJanusz>();
}
3

Still the same error

4

Where do you set ‘mainCamera’ ?

And just so you know, there is already a static for that. “Camera.main”

So, try in Start(), to assign it like that.

Of course, those 2 scripts you’re searching for have to be on the main camera’s game object, also, for it to work.

5

You’re doing the same thing in the other script. Understand what he explained and apply the fix.

6

Why on earth do you have a static Gameobject called mainCamera in both scripts?

7

Ok, thank you so much guys for help

8

You’re welcome. :slight_smile: