uGUIでドラッグドロップ

シンプルなドラッグドロップを勉強がてら

ドラッグのScript

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

[RequireComponent(typeof(Image))]
public class DragObject : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    private Transform canvasTran;
    private GameObject draggingObject;

    void Awake()
    {
        canvasTran = transform.parent.parent;
    }   

    public void OnBeginDrag(PointerEventData pointerEventData)
    {
        CreateDragObject();
        draggingObject.transform.position = pointerEventData.position;
    }

    public void OnDrag(PointerEventData pointerEventData)
    {
        draggingObject.transform.position = pointerEventData.position;
    }

    public void OnEndDrag(PointerEventData pointerEventData)
    {
        gameObject.GetComponent<Image>().color = Vector4.one;
        Destroy(draggingObject);
    }

    // ドラッグオブジェクト作成
    private void CreateDragObject()
    {
        draggingObject = new GameObject("Dragging Object");
        draggingObject.transform.SetParent(canvasTran);
        draggingObject.transform.SetAsLastSibling();
        draggingObject.transform.localScale = Vector3.one;

        // レイキャストがブロックされないように
        CanvasGroup canvasGroup = draggingObject.AddComponent<CanvasGroup>();
        canvasGroup.blocksRaycasts = false;

        Image draggingImage = draggingObject.AddComponent<Image>();
        Image sourceImage = GetComponent<Image>();

        draggingImage.sprite = sourceImage.sprite;
        draggingImage.rectTransform.sizeDelta = sourceImage.rectTransform.sizeDelta;
        draggingImage.color = sourceImage.color;
        draggingImage.material = sourceImage.material;

        gameObject.GetComponent<Image>().color = Vector4.one * 0.6f;
    }
}

ドロップのほうのScript

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class DropObject : MonoBehaviour, IDropHandler, IPointerEnterHandler, IPointerExitHandler
{
    public Image iconImage;
    private Sprite nowSprite;

    void Start()
    {
        nowSprite = null;
    }

    public void OnPointerEnter(PointerEventData pointerEventData)
    {
        if(pointerEventData.pointerDrag == null) return;
        Image droppedImage = pointerEventData.pointerDrag.GetComponent<Image>();
        iconImage.sprite = droppedImage.sprite;
        iconImage.color = Vector4.one * 0.6f;
    }

    public void OnPointerExit(PointerEventData pointerEventData)
    {
        if(pointerEventData.pointerDrag == null) return;
        iconImage.sprite = nowSprite;
        if(nowSprite == null)
            iconImage.color = Vector4.zero;
        else
            iconImage.color = Vector4.one;
    }
    public void OnDrop(PointerEventData pointerEventData)
    {
        Image droppedImage = pointerEventData.pointerDrag.GetComponent<Image>();
        iconImage.sprite = droppedImage.sprite;
        nowSprite = droppedImage.sprite;
        iconImage.color = Vector4.one;
    }
}

DragするImageのついたオブジェクトにDragObject.csをアタッチ
ドラッグされるほうのオブジェクトにDropObject.csをアタッチで完了