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

using System.Collections;
using UnityEngine.UI;
using System.Collections.Generic;
using UnityEngine;
using TMPro;
public class HotbarSlotUI : MonoBehaviour
{
  public int slotIndex;

  private PlayerController playerController;

  private InventoryItem invItem;

  [SerializeField] private Image border;
  [SerializeField] private Image image;
  [SerializeField] private TextMeshProUGUI quantityText;

  private void Start()
  {
    playerController = GameObject.FindGameObjectWithTag("Player").GetComponent<PlayerController>();
    PlayerController.OnActiveSlotChanged += CheckSelectedSlot;
    CheckSelectedSlot();
  }

  private void CheckSelectedSlot()
  {
    if (playerController.activeHotbarSlot == slotIndex)
    {
      border.gameObject.SetActive(true);
    }
    else
    {
      border.gameObject.SetActive(false);
    }
  }

  public void SetInventoryItem(InventoryItem newInvItem)
  {
    invItem = newInvItem;
    UpdateSlot();
  }

  private void UpdateSlot()
  {
    image.sprite = invItem?.item?.sprite ?? null;
    quantityText.SetText(invItem?.count.ToString() ?? "");
    if (image.sprite == null)
    {
      image.color = new Color(0, 0, 0, 0);
    }
    else
    {
      image.color = Color.white;
    }
  }
}