What is the meaning of this error ?

Can you show the code from line 35? (Garab.cs)

 

that is the line number 35
gameController.AddScore (scoreValue) ;

AddScore is a method of another script

and ( Scorevalue )
is an integer

 

Have you assigned gameController somewhere?

 

ok that is the code of script ( Garab )

using UnityEngine;
using System.Collections;

public class Garab : MonoBehaviour {



public int scoreValue;
private Done_GameController gameController;

void Start ()
{
GameObject gameControllerObject = GameObject.FindGameObjectWithTag ("GameController");
if (gameControllerObject != null)
{
gameController = gameControllerObject.GetComponent <Done_GameController>();
}
if (gameController == null)
{
Debug.Log ("Cannot find 'GameController' script");
}
}

void OnTriggerEnter (Collider other)
{
if (other.tag == "Enemy" )
{
return;
}





gameController.AddScore (scoreValue) ;
Destroy (other.gameObject);
Destroy (gameObject);
}
}


as you can see i called another script called Done_GameController then i create an object from it
to use it for adding score
but this script ( Garab )
make alot of problem in the game

and the error on the picture u saw in above i dont understand the meaning of it !

 

A null reference exception means you are attempting to access memory with nothing in it.

Code (csharp):

1.  
2. MyObject newObject;
3. MyObject.ToString();
4.  

This will throw a null reference exception because newObject was never given a value. The fix for the code would be like this.

Code (csharp):

1.  
2. MyObject newObject = new MyObject();
3. MyObject.ToString();
4.  

The ToString method now has an actual object to reference and thus no longer throws an error. In unity newObject can be set in another way, by setting the variable to public and dragging a reference into the inspector slot. Somehow in your code a variable is not being set to a value correctly.

Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class Garab : MonoBehaviour {
6. public int scoreValue;
7. private Done_GameController gameController;
8.  
9. void Start () {
10.    GameObject gameControllerObject = GameObject.FindGameObjectWithTag ("GameController");
11.    if (gameControllerObject != null) {
12.       gameController = gameControllerObject.GetComponent <Done_GameController>();
13.    }
14.    if (gameController == null) {
15.       Debug.Log ("Cannot find 'GameController' script");
16.    }
17. }
18.  
19. void OnTriggerEnter (Collider other) {
20.       if (other.tag == "Enemy" ) {
21.          return;
22.       }
23.       gameController.AddScore (scoreValue) ;
24.       Destroy (other.gameObject);
25.       Destroy (gameObject);
26.    }
27. }
28.