UnityAtoms_UI_Hearts_Bar.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityAtoms.BaseAtoms;

public class UnityAtoms_UI_Hearts_Bar : MonoBehaviour
{
    [SerializeField] private FloatVariable _Value;
    public float Value { set { _Value.Value = value; } get { return _Value.Value; } }

    [SerializeField] private FloatVariable _MaxValue;
    public float MaxValue { set { _MaxValue.Value = value; } get { return _MaxValue.Value; } }

    public GameObject UnitPrefab;
    public Vector3 spacing;
    List<GameObject> Units;

    [Header ("Properties")]
    bool initOnAwake;

    private void Awake ()
    {
        Units = new List<GameObject> ();
        if (initOnAwake)
            Value = MaxValue;

        _Value.Changed.Register (Handle_ValueUpdate);
        _MaxValue.Changed.Register (Handle_MaxValueUpdate);
        
        // these aren't needed if you toggle on the "Trigger Event on OnEnable" property of the atom.
        // Handle_ValueUpdate (Value);
        // Handle_MaxValueUpdate (MaxValue);
    }

    void Handle_ValueUpdate (float val)
    {
        for (int i = 0; i < Units.Count; i++)
        {
            if (i < val)
                Units[i].SetActive (true);
            else
                Units[i].SetActive (false);

        }
    }
    void Handle_MaxValueUpdate (float val)
    {
        for (int i = Units.Count; i < Mathf.CeilToInt (val); i++)
        {
            var item = Instantiate (UnitPrefab, transform.position + (spacing * i), Quaternion.identity, transform);

            item.TryGetComponent<SpriteRenderer> (out SpriteRenderer sprite);
            sprite.sortingOrder = i;

            Units.Add (item);
        }
    }
}