Unity拖拽UI界面元素

1.新建场景，在场景中创建一个UI的Panel。

2.创建脚本Drag.cs，将脚本附加到Panel上。

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

public class Drag : MonoBehaviour, IDragHandler,IBeginDragHandler
{
    //记录初始鼠标与元素的偏移量
    private Vector3 offset;

    public void OnBeginDrag(PointerEventData eventData)
    {
        offset = transform.position - new Vector3(eventData.position.x, eventData.position.y, transform.position.z);
    }

    public void OnDrag(PointerEventData eventData)
    {
        transform.position = offset + new Vector3(eventData.position.x, eventData.position.y, transform.position.z);
    }
}