NullReferenceException: Object reference not set to an instance of an object

Questions & Answers
1

i am trying to make a command where: you press the space bar button and the health bar goes down by 10 health, but i am accessing this health variable from another script.

this time i am having another issue with this code.

during play mode when i pressed the space bar button to lower the health, the health bar doesnt change and this error comes up : NullReferenceException: Object reference not set to an instance of an object

this is my code:

using UnityEngine;
using System.Collections;

public class keyboard : MonoBehaviour {

	private healthgui heal;

	// Use this for initialization
	void awake () {
		heal = this.gameObject.GetComponent<healthgui>();
	
	}
	
	// Update is called once per frame
	void Update () {

		int newHealth;
		int gethealth;

		if (Input.GetKey(KeyCode.Space)) {

			gethealth = heal.health;
			newHealth = heal.health - 10;
			heal.health = newHealth;

				}

	
	}
}

heres my other code just incase

public class healthgui : MonoBehaviour {
	//these floats are used to easily configure the GUI Image//

	//health image size and positioning floats//
	public float guiHealthWidth;
	public float guiHealthHeight;
	public float guiHealthDistLeft;
	public float guiHealthDistTop;


	public int health = 100;
	public GUIStyle healthbar;

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void OnGUI () {

		//Displays health Hud//
	GUI.Box (new Rect(
			(Screen.width/16) * guiHealthDistLeft,
			(Screen.height/16) * guiHealthDistTop,
			(Screen.width/16) * guiHealthWidth,
			(Screen.height/16) * guiHealthHeight),
			 health.ToString(),healthbar);


	}
}
2

Landern was on the right track with his answer, just a few details off.

the function should be Awake, and not awake. I know, it’s silly, but that’s how it is.

void Awake () {
        heal = this.gameObject.GetComponent<healthgui>();
        if (heal == null)
            Debug.Log("Heal was not found on the current gameobject");
        else
            Debug.Log("Was able to find the component Heal");
    }