Heart bar problem with list/array

Question

Hi guys, I'm tryi'n to do a life bar with heart and not a slider. For that i've created an transform array to get child and then stack them in a list, and later call it to enable or disable the game object. Seems unity doesn't like the way i've done it, can anyone take a look to explain me my errors :D Thanks :)

 public class Health : MonoBehaviour
 {
     public int health = 3;
     int maxLife;
 
     public Sprite fullHeart;
     public Sprite emptyHeart;
 
     [SerializeField] Transform[] Lifes;
     List<GameObject> childObjects;
 
     // Start is called before the first frame update
     void Start()
     {
 
     Lifes = GetComponentsInChildren<Transform>();
     List<GameObject> childObjects = new List<GameObject>();
     foreach(Transform child in Lifes)
         {
             childObjects.Add(child.gameObject);
         }
     }
 
     // Update is called once per frame
     void Update()
     {
       SetLife();
     }
 
     void SetLife(){
         for (int i = 1; i < Lifes.Length; i++)
         {
             if (i < health)
             {
                childObjects[i].SetActive(true); 
             }else{
                 childObjects[i].SetActive(false);
             }
             
         }
     }
 }

Answer 1

Answer by The_Three_Vs · Mar 31, 2020 at 03:29 PM

Lists are 0-indexed; you'll need to change your for loop to

 for (int i = 1; i <= Lifes.Length; i++)
 {
     if (i <= health)
     {
         childObjects[i - 1].SetActive(true); 
     }else{
         childObjects[i - 1].SetActive(false);
     }     
 }

If, for example, the length of Lifes is 3 and current health is 2, this new loop will check if 1 is less than or equal to 2, which it is, and set the 1st childObject, which has a list index of 0, to be active. The loop will then check if 2 is less than or equal to 2, which it is, and set the 2nd childObject, which has a list index of 1, to be active. The loop will then check if 3 is less than or equal to 2, which it isn't, and set the 3rd and last childObject, which has a list index of 2, to be inactive. Since i is now 4 and greater than Lifes.Length, the loop won't try to access a nonexistent heart and will terminate.

Hope this helps!

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Answer 2

Answer by Mrintoxx · Mar 31, 2020 at 05:44 PM

Done for that, i've understanded my mistake.

but the code you show me, it's the same doing that ? :

 for (int i = **0**; i < Lifes.Length; i++)
         {
         
             if (i <= health)
             {
             childObjects[i].SetActive(true); 
             }else{
             childObjects[i].SetActive(false);
             }

But i think my problem is not here, i've got an error :"object reference not set" in this part of code :

     void Start()
     {
 
     Lifes = GetComponentsInChildren<Transform>();
     List<GameObject> childObjects = new List<GameObject>();
     foreach(Transform child in Lifes)
         {
             childObjects.Add(child.gameObject);
         }
     }

I'm getting the child of the GameObject in an Transform array and then to a gameobject list.

But in the inspector the parent gets inside the array, for this reason the for loop was starting at 1.

alt text

any idea ?

capture.png (14.2 kB)

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The_Three_Vs · Mar 31, 2020 at 06:51 PM 0

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GetComponentInChildren searches all the children, and the gameObject that called the function, for the specified component. You can fix the issue by adding if if statement if(child != transform) when adding elements to childObjects. You can then use childObjects.Count ins$$anonymous$$d of Lifes.Length, since childObjects will have the correct length even if the objects are inactive. If you want to maintain Lifes, you will have to create a temporary array without the parent, then assign it to Lifes. For example:

 Transform[] temp = new Transform[Lifes.Length - 1];
 for(int i = 0; i < Lifes.Length; i++)
 {
     if(Lifes[i] != transform)
     {
         childObjects.Add(Lifes[i].gameObject);
         temp[i - 1] = Lifes[i];
     }
 }
 Lifes = temp;

Heart bar problem with list/array

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