Slider is not instantiating correctly nor is automatically updating

I'm using a slider to act as a health bar for an enemy. I have a prefab that is basically a canvas with a slider inside of it. I link this prefab to my enemy inside a script called Healthbar. Inside Healthbar I have the following code.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5.  
6. public class HealthBar : MonoBehaviour
7. {
8.     [SerializeField] GameObject HealthBarObject;
9.     [SerializeField] float MaxHealth;
10.     [SerializeField] float CurrentHealth;
11.     Slider SlideObj;
12.  
13.     public float GetMaxHealth() { return MaxHealth; }
14.     public float GetCurrentHealth() { return CurrentHealth; }
15.     public void AdjustCurrentHealth(float val) { CurrentHealth -= val; }
16.     public void SetCurrentHealth(float val) { CurrentHealth = val; }
17.  
18.     // Start is called before the first frame update
19.     void Start()
20.     {
21.         Vector3 point = Camera.main.WorldToScreenPoint(new Vector3(transform.position.x, transform.position.y, transform.position.z));
22.         point = new Vector2(point.x, point.y + 45);
23.         var sliderCanvas = Instantiate(HealthBarObject, new Vector2(0, 0), Quaternion.identity);
24.         var sliderObj = sliderCanvas.transform.Find("Slider");
25.         sliderObj.transform.position = point;
26.  
27.         SlideObj = HealthBarObject.GetComponentInChildren<Slider>();
28.         SlideObj.minValue = 0.0f;
29.         SlideObj.maxValue = 1.0f;
30.         SlideObj.value = 1.0f;
31.     }
32.  
33.     // Update is called once per frame
34.     void Update()
35.     {
36.         SlideObj.value = SlideObj.value - (Time.deltaTime * 0.1f);
37.     }

All I am doing is automatically decreasing the slider value to test.

The problem is this does not work. The slider will not change. Moreover when I stop the game and start it again, the health instantiates with an updated value. I have included two screen shots: one where the health bar is full and another where the health bar is depleted. The problem here is that the depleted health bar is where the slider starts. When I start a new game the slider starts where it left off previously. How is that possible if I am instantiating a whole new canvas and slider? Shouldn't it always reset to max?

 

I figured this out. Line 23 I instantiate my object but I am going after the prefab, not the instantiated object which I should be referencing since that is what I want to change, that is what is on the screen.

Silly mistake.

 

hi david, I'm actually having the same problem right now. I completely understand where the problem lies (and your reply makes total sense), however I'm not sure how I could use the instantiated object in the code instead of the prefab itself.

Could you please help with how you've done it?