gather-and-defend/Assets/Scripts/Ally/AllyUpgrade.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class AllyUpgrade : MonoBehaviour, IPointerClickHandler
{
    [SerializeField]
    private GameObject upgradeUI;
    [SerializeField]
    private List<UnitCard> upgradeUnitCardList = new List<UnitCard>();
    [SerializeField]
    private List<GameObject> upgradePrefabList = new List<GameObject>();
    private GameObject _instance = null;

    public void OnPointerClick(PointerEventData eventData)
    {
        if (eventData.button == 0)  //Left click
        {
            Debug.Log("Event clicked...");
            if (!_instance)
            {
                GameObject sceneCanvas = GameObject.Find("Canvas");
                if (sceneCanvas != null)
                {
                    Canvas canvas = sceneCanvas.GetComponent<Canvas>();
                    if (canvas == null)
                    {
                        Debug.Log("Canvas introuvable...");
                    }
                    else
                    {
                        _instance = Instantiate(upgradeUI, Camera.main.WorldToScreenPoint(transform.position), Quaternion.identity, canvas.transform);
                    }
                }
                Debug.Log(_instance.transform.position);
                Debug.Log(Camera.main.WorldToScreenPoint(transform.position));

                GameObject upgradeParent = _instance.transform.GetChild(0).gameObject;
                for (int i = 0; i < upgradeParent.transform.childCount; i++)
                {
                    GameObject upgradeEnfant = upgradeParent.transform.GetChild(i).gameObject;
                }
            }
            else
            {
                Destroy(_instance);
                Debug.Log("Destroyed....");
            }

        }
    }
}