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