Unity3D UGUI窗口拖拽

在开发UGUI时

我们时常需要做一个窗口拖拽的功能

先上代码

using UnityEngine;
using UnityEngine.EventSystems;

public class DragWindow : MonoBehaviour,IPointerDownHandler,IDragHandler
{
    private Vector2 localMousePos;
    private Vector3 planeLocalPos;
    private RectTransform targetObject;
    private RectTransform parentRectTransform;
    private RectTransform targetRectTransform;

    void Awake()
    {
        targetObject = this.transform.GetComponent<RectTransform>();
        if (targetObject == null)
        {
            targetObject = transform as RectTransform;
        }

        parentRectTransform = targetObject.parent as RectTransform;
        targetRectTransform = targetObject as RectTransform;

    }

    public void OnPointerDown(PointerEventData data)
    {
        planeLocalPos = targetRectTransform.localPosition;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(parentRectTransform, data.position, data.pressEventCamera, out localMousePos);
        targetObject.gameObject.transform.SetAsLastSibling();
    }

    public void OnDrag(PointerEventData data)
    {

        Vector2 localPointerPosition;
        if (RectTransformUtility.ScreenPointToLocalPointInRectangle(parentRectTransform, data.position, data.pressEventCamera, out localPointerPosition))
        {
            Vector3 offsetToOriginal = localPointerPosition - localMousePos;

            targetObject.localPosition = planeLocalPos + offsetToOriginal;
        }
    }
}

使用方法：

直接将此脚本添加到需要拖拽的窗口就好

此脚本使用了UGUI内置的事件接口IPointerDownHandler和IDragHandler

并在接口方法OnPointerDown和OnDrag实现了相应的拖拽逻辑