Cud_ s_05 - Object reference not set to an instance of an object

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1

in my levelManager.cs file i have this method

public void levelOver(){
	print ("check"); // this isn't triggering
	if(Bricks.bricks<=0){		
	LoadNextLevel();}
}

in my bricks.cs i have this

void OnCollisionEnter2D(Collision2D collision){
	if(isbreakable){
	handlehits();}
}

void handlehits(){

	timesHit++;
	int maxHits=hitSprites.Length; // i don't need to set it to length +1 because of the way i worked with my sprites.
	if (timesHit>=maxHits){
		bricks--; // bricks count
		levelManager.levelOver(); 
		Destroy(gameObject);
	}
	else {
		loadSprite();
		}
	}

i’ve been getting this message “Object reference not set to an instance of an object” even though my code is pretty close to the one on the video =(

2

You’ve not said where you are getting this error?

Question… you’ve renamed a few things… what is the name of the brick class? Is it Bricks, or bricks?

3

on my bricks.cs file

using UnityEngine;
using System.Collections;

public class Bricks : MonoBehaviour {
public int maxHits;
public Sprite[] hitSprites;
public static int bricks=0;

public LevelManager levelManager;
private int timesHit=0;
public bool isbreakable;
   void Start(){

The error i mentioned appears whenever a bricks is supposed to be destroyed and the levelOver() (or BrickDestroyed(), as they use) function should be called.
The brick doesn’t even get destroyed if i leave the code like this.

if (timesHit>=maxHits){
		bricks--;
		levelManager.levelOver();
		Destroy(gameObject);

if i leave it like THIS:

	if (timesHit>=maxHits){
		bricks--;
		Destroy(gameObject);
		levelManager.levelOver();

it gets destroyed but the error message is risen anyway

4

Hi @David_Spira, first thing to note, Unity requires the names of the files and classes to be the same. At the moment you have bricks.cs and Bricks as the class name.

Second thing, if you consider the order of events you are asking the code to perform here;

 if (timesHit>=maxHits){
	bricks--;
	levelManager.levelOver();
	Destroy(gameObject);
  • deduct 1 from the bricks count
  • call loadLevel() from levelManager

I’m assuming that this method loads another scene? If so, this would explain why your Destroy(gameObject) code is not called, as you have just destroyed the current scene, all of the objects in it and loaded a new one.

But when you do it around this way;

if (timesHit>=maxHits){
	bricks--;
	Destroy(gameObject);
	levelManager.levelOver();

You are saying;

  • deduct 1 from the bricks count
  • destroy the game object
  • call loadLevel() from levelManager

Can you post up your levelManager code also please.

5

the Bricks.cs file name is actually Bricks.cs, not as i wrote before, bricks.cs =)

 using UnityEngine;
using System.Collections;

public class LevelManager : MonoBehaviour {

public void LoadLevel(string name){
	Application.LoadLevel(name);
}	
public void LoadNextLevel(){
	Application.LoadLevel(Application.loadedLevel+1);
}



public void levelOver(){
	print ("check");
	if(Bricks.bricks<=0){		
	LoadNextLevel();}
}

public void QuitRequest(){
	Debug.Log("quit");
	Application.Quit ();
}

 }
6

I think you have a class variable that is getting declared but not initialized. It’s a bit difficult to say without seeing the entire class. Make sure each variable has a value before you attempt to use it. If you can’t find it, pastebin the entire file please.

7

Hi,

Just had the same issue and i have hunted high and low. turns out i missed something somewhere :slight_smile:

Brick.cs

void Start() function.

I had missed this line below the timesHit = 0

levelManager = GameObject.FindObjectOfType<LevelManager>();

Hope it helps anyone with the same issue.

2 Likes
8

Thanks @anthukne , this really helped me.

I had to write is like this:

levelManager = GameObject.FindObjectOfType<LevelManager>();

Actually, it appears this forum is reformatting what I wrote, leaving the <LevelManager> part out, so I had to use '. I think the same happened to your post.

BTW, I went back over this video, and it appears that this line of code was already in his Bricks script (as you can see in the first seconds of the video) so we both missed this line somewhere in a previous lecture.

2 Likes
9

Because the forum supports HTML, it assumes that anything between < and > tags is HTML.

You can either use the ` character before and after, or, use the preformatted text icon on the composer toolbar.

Hope this helps :slight_smile: