Health System

Hello,
I have a problem on the Life / damage button, now I will explain the anomaly that is hanging over me:

I did something like this:



To make the life and damage buttons work I made this C # script

Code (csharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5.  
6. public class HealthBarSlider : MonoBehaviour
7. {
8.  
9.     public Slider slider;
10.     public Button buttonVita;
11.       public Button buttonDanno;
12.  
13.  
14.      //public HealthSystem healthSystem = new HealthSystem();
15.  
16.     // Start is called before the first frame update
17.     void Start()
18.    
19.     {
20.          
21.         Button btnVita = buttonVita.GetComponent<Button>();
22.         Button btnDanno = buttonDanno.GetComponent<Button>();
23.  
24.         btnVita.onClick.AddListener(ClickVita);
25.         btnDanno.onClick.AddListener(ClickDanno);
26.  
27. }
28.  
29. void ClickVita(){
30.     health(10);
31.      Debug.Log ("Vita: " + GetHealth());
32. }
33.     void ClickDanno(){
34.  
35.     damage(10);
36.      Debug.Log ("Danno: " + GetHealth());
37. }
38.  
39. public void health(int healthAmount){
40.  
41. slider.value+=healthAmount;
42.  
43.     }
44.  
45.       public void damage(int healthAmount){
46.  
47. slider.value-=healthAmount;
48.  
49.     }
50.  
51.       public float GetHealth(){
52.       return (float) slider.value;
53.   }
54. void Update()
55.     {
56.        
57.     }
58.  
59.     }
60.  

And so far everything is ok. If I press the button, it gives Life and decreases and increases the slider that is at the bottom left.

Then I tried to divide the code into 2 scripts like this:

Code (csharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5.  
6. public class HealthSystem
7. {
8.    
9. private Slider slider;
10.  
11.     public void health(int healthAmount){
12.  
13. slider.value+=healthAmount;
14.  
15.     }
16.  
17.       public void damage(int healthAmount){
18.  
19. slider.value-=healthAmount;
20.  
21.     }
22.  
23.       public float GetHealth(){
24.       return (float) slider.value;
25.   }
26. }

Code (csharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5.  
6. public class HealthBarSlider : MonoBehaviour
7. {
8.  
9.    public HealthSystem healthSystem;
10.  
11.     public Button buttonVita;
12.       public Button buttonDanno;
13.  
14.  
15.      //public HealthSystem healthSystem = new HealthSystem();
16.  
17.     // Start is called before the first frame update
18.     void Start()
19.    
20.     {
21.          
22.         Button btnVita = buttonVita.GetComponent<Button>();
23.         Button btnDanno = buttonDanno.GetComponent<Button>();
24.  
25.         btnVita.onClick.AddListener(ClickVita);
26.         btnDanno.onClick.AddListener(ClickDanno);
27.  
28. }
29.  
30. void ClickVita(){
31.     healthSystem.health(10);
32.      Debug.Log ("Vita: " + healthSystem.GetHealth());
33. }
34.     void ClickDanno(){
35.  
36.     healthSystem.damage(10);
37.      Debug.Log ("Danno: " + healthSystem.GetHealth());
38. }
39.  
40.  
41. void Update()
42.     {
43.        
44.     }
45.  
46.     }

But when I try to use the life or damage button I get this error:



How can I handle this problem?

Thank you

 

A NullReferenceException generally means that you aren't properly initializing your variables. I suggest you double-check the values of "healthSystem" in your HealthBarSlider script and "slider" in your HealthSystem script.

 

Assign the healthSystem component to the script.

 

Hi, could you tell me how I could do it? thank you