evershade/Assets/Scripts/Inventory/InventoryItem.cs

using UnityEngine;
using UnityEngine.EventSystems;


// Drag Dropable
public class InventoryItem : MonoBehaviour, IPointerDownHandler, IBeginDragHandler, IEndDragHandler
{
    [SerializeField] private Canvas canvas;
    public GameItem GameItem;
    private RectTransform _rectTransform;
    private CanvasGroup canvasGroup;

    private void Awake()
    {
        _rectTransform = GetComponent<RectTransform>();
        canvasGroup = GetComponent<CanvasGroup>();
    }

    // Update is called once per frame
    private void Update()
    {
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        canvasGroup.alpha = 0.6f;
        canvasGroup.blocksRaycasts = false;
    }

    /*public void OnDrop(PointerEventData eventData)
    {
    }*/

    public void OnEndDrag(PointerEventData eventData)
    {
        canvasGroup.alpha = 1.0f;
        canvasGroup.blocksRaycasts = true;
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("OnPointerDown");
    }

    public void SetItem(GameItem item)
    {
        GameItem = item;
    }

    public void OnDrag(PointerEventData eventData)
    {
        _rectTransform.anchoredPosition += eventData.delta / canvas.scaleFactor;
    }
}