harvestdale-unity/Assets/Scripts/UI/SlotUI.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
public class SlotUI : MonoBehaviour, IDropHandler
{
  public int slotIndex;
  [SerializeField] private GameObject contentObject;
  [SerializeField] private InventoryItem inventoryItem;
  [SerializeField] private Image itemSpriteImage;
  [SerializeField] private TMPro.TextMeshProUGUI quantityText;

  private Inventory playerInventory;
  private void Start()
  {
    UpdateSlot();
    contentObject.GetComponent<DraggableSlotContentUI>().slotIndex = slotIndex;
    playerInventory = GameObject.FindGameObjectWithTag("Player").GetComponent<Inventory>();
  }
  public void SetInventoryItem(InventoryItem newInventoryItem)
  {
    inventoryItem = newInventoryItem;
    UpdateSlot();
  }

  private void UpdateSlot()
  {
    if (inventoryItem != null)
    {
      itemSpriteImage.sprite = inventoryItem?.item?.sprite ?? null;
      if (itemSpriteImage.sprite == null)
      {
        itemSpriteImage.color = new Color(0, 0, 0, 0);
      }
      else
      {
        itemSpriteImage.color = new Color(255, 255, 255, 1);
      }

      quantityText.SetText(inventoryItem.count != 0 ? inventoryItem.count.ToString() : "");
    }
    else
    {
      itemSpriteImage.sprite = null;
      quantityText.SetText("");
      itemSpriteImage.color = new Color(0, 0, 0, 0);
    }

  }



  public void OnDrop(PointerEventData eventData)
  {
    Debug.Log("DROP");
    DraggableSlotContentUI dropped = eventData.pointerDrag.GetComponent<DraggableSlotContentUI>();
    playerInventory.SwapItems(dropped.slotIndex, slotIndex);
  }

}