Error with Scorekeeper

sreshtiyer · December 5, 2021, 2:24pm

So I’m at the part where I coded in for the score to reset after loading the game. But then I get this error

NullReferenceException: Object reference not set to an instance of an object
LevelManager.LoadGame () (at Assets/Scripts/LevelManager.cs:18)

And this is my level manager script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

public class LevelManager : MonoBehaviour
{
    [SerializeField] float sceneLoadDelay = 2f;
    ScoreKeeper scoreKeeper;

    void Awake() 
    {
        scoreKeeper = FindObjectOfType<ScoreKeeper>();
    }
    
    public void LoadGame()
    {
        scoreKeeper.ResetScore();
        SceneManager.LoadScene("Game");
    }

    public void LoadMainMenu()
    {
        SceneManager.LoadScene("MainMenu");
    }

    public void LoadGameOver()
    {
        StartCoroutine(WaitAndLoad("GameOver", sceneLoadDelay));
    }

    public void QuitGame()
    {
        Debug.Log("Quit the Game");
        Application.Quit();
    }

    IEnumerator WaitAndLoad(string sceneName, float delay)
    {
        yield return new WaitForSeconds(delay);
        SceneManager.LoadScene(sceneName);
    }


}

Basically the script is telling me that I cant reset the score at line 18 because my ScoreKeeper object doesnt exist. But when I check the hierarchy, I can still see the ScoreKeeper game object under DontDestroyOnLoad. I’m not entirely sure why this error pops up. I can still load the main menu, but I cant go into the Game menu from the Game over screen or from the Main Menu because it gives me this error.

And this is my ScoreKeeper script in case there’s something wrong there

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ScoreKeeper : MonoBehaviour
{
    int score = 0;

    static ScoreKeeper instance;

    void Awake()
    {
        ManageSingleton();
    }

    void ManageSingleton()
    {
        if(instance != null)
        {
            gameObject.SetActive(false);
            Destroy(gameObject);
        }
        else
        {
            instance = this;
            DontDestroyOnLoad(gameObject);
        }
    }

    public int GetScore()
    {
        return score;
    }


    public void ModifyScore(int value)
    {
        score += value;
        Mathf.Clamp(score, 0, int.MaxValue);
        Debug.Log(score);
    }

    public void ResetScore()
    {
        score = 0;
    }
}

What could be causing this error?

Nina · December 5, 2021, 7:45pm

Hi,

Unity executes its event methods in an arbitrary order. Maybe the Awake method of the LevelManager got executed before the Awake method of the ScoreKeeper. Try to rename the Awake method in the LevelManager to Start. Then save your script and test your game again.

Did this fix it?