NarKampen/Assets/Scripts/DropZone.cs

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

public class DropZone : MonoBehaviour, IDropHandler, IPointerEnterHandler, IPointerExitHandler {

    public void OnDrop(PointerEventData eventData) {
        Draggable d = eventData.pointerDrag.GetComponent<Draggable>();
        if (d != null) {
            d.placeholderParent = this.transform;
        }
    }

    public void OnPointerEnter(PointerEventData eventData) {
        if (eventData.pointerDrag == null) {
            return;
        }

        Draggable d = eventData.pointerDrag.GetComponent<Draggable>();
        if (d != null) {
            d.placeholderParent = this.transform;
        }
    }

    public void OnPointerExit(PointerEventData eventData) {
        if (eventData.pointerDrag == null) {
            return;
        }

        Draggable d = eventData.pointerDrag.GetComponent<Draggable>();
        if (d != null && d.placeholderParent == this.transform) {
            d.placeholderParent = d.parent;
        }
    }
}