GUI object error

Hi all,

I'm working on a health GUI bar & I need a little help fixing an object error that I'm getting.

The error:
NullReferenceException: Object reference not set to an instance of an object
GuiTest.Update () (at Assets/scripts/GuiTest.cs:51)

The code:

Code (CSharp):

1. /// <summary>
2. /// GUI test.
3. /// attach this to corresponding UI objects
4. /// </summary>
5.  
6. using UnityEngine;
7. using UnityEngine.UI;
8. using System.Collections;
9.  
10. public class GuiTest : MonoBehaviour
11. {
12.  
13.     private int startHealth = 100;
14.  
15.     public Text txtHealthString; //text field display
16.  
17.     public GameObject guiHealthBarObj; //health bar display
18.  
19.     public Object guiHealthBarImg; //health bar image
20.  
21.     private int testValue = 10;
22.  
23.     private int updatedValue = 0;
24.     //private int newValue = 0;
25.  
26.     // Use this for initialization
27.     void Awake ()
28.     {
29.  
30.         //updatedValue.ToString();
31.  
32.         txtHealthString.text = "Start Health: " + startHealth;
33.  
34.         txtHealthString = GetComponent<Text>();
35.         print("starting: " + startHealth);
36.         print("updated value: " + updatedValue);
37.  
38.     }
39.     void Update ()
40.     {
41.         //txtHealthString.text = startHealth.ToString ();
42.      
43.         //print (txtHealthString);
44.         //updatedValue.ToString();
45.         //startHealth.ToString();
46.         //txtHealthString = GetComponent<Text>();
47.  
48.             if (Input.GetKeyUp ("up"))
49.             {
50.                 AddInt ();
51.                 txtHealthString.text = updatedValue.ToString ();
52.              
53.                 print("updated value: " +updatedValue);
54.             }
55.          
56.             if (Input.GetKeyUp ("down"))
57.             {
58.                 SubInt ();
59.                 txtHealthString.text = updatedValue.ToString ();
60.          
61.                 //else{return;}
62.             print("updated value: " +updatedValue);
63.             }
64.  
65.  
66.     }
67.  
68.     void AddInt()
69.     {
70.  
71.         updatedValue = startHealth + testValue;
72.         txtHealthString = GetComponent<Text>();
73.         //print(updatedValue);
74.     }
75.     void SubInt()
76.     {
77.  
78.         updatedValue = startHealth - testValue;
79.         txtHealthString = GetComponent<Text>();
80.         //print(updatedValue);
81.     }
82.     /*
83.     void UpdateGraphic()
84.     {
85.         if (updatedValue == 75)
86.         {
87.             //guiTexture.texture = "";
88.         }
89.     }*/
90.  
91.  
92.     // Update is called once per frame
93.  
94.     }
95.  
96.  

Please help me figure out what I'm doing wrong.

Thank you in advance

 

Does txtHealthString have a text object assigned to it?

 

Yes it does...

 

Question: If txtHealthString is assigned in the inspector, why do you keep on GetComponent'ing for it? Maybe the GetComponent is making it null during runtime
Question 2: More than 1 instance of the script in the scene? eg on an object where there is no text component?

 

thanks hpjohn, got rid of the GetComponent & fixed the error...I suppose I was confused with implementing the code