Unity 实现界面拖拽功能的脚本，通过IDragHandler 实现

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

namespace Assets.Scripts._1024
{
    class EVENTdome : MonoBehaviour, IPointerDownHandler, IBeginDragHandler, IDragHandler
    {

        //Unity  事件处理的几种方式
        //1  通过编辑器绑定方式
        //2：addlistener
        //3:实现接口
        //4：自定义框架 
        //1，2 绑定的同一个事件 ，比较隐秘，不建议用1
        //光标类
        //IPointerEnterHandler pointerEnterHandler;
        //IPointerDownHandler pointerDownHandler;
        //IPointerExitHandler pointerExitHandler;
        //IPointerMoveHandler pointerMoveHandler;
        //IPointerUpHandler pointerUpHandler;
        //拖拽类
        //IBeginDragHandler beginDragHandler;
        //IDragHandler dragHandler;
        //IEndDragHandler endDragHandler;
        //IDropHandler dropHandler;

        //点选类(可点选 的空间)
        //IUpdateSelectedHandler updateSelectedHandler;
        //ISelectHandler selectHandler;
        //IDeselectHandler deselectHandler;
        //输入类
        //IScrollHandler scrollHandler;
        //IMoveHandler moveHandler;
       // ISubmitHandler submitHandler;
        //ICancelHandler cancelHandler;

        public void OnBeginDrag(PointerEventData eventData)
        {
            throw new NotImplementedException();
        }
        // 拖拽点和轴心线向量
        Vector3 diss;
        //T
        public void OnDrag(PointerEventData eventData)
        {

            Camera camera = eventData.pressEventCamera;
            Vector3 vector3 = eventData.position;
            // 仅仅适用于canvas 是  overlay的模式 
            // this.transform.position = eventData.position;
            // camery 模式需要转换 
            Vector3 worldPosition;
            RectTransform rectTransform = this.transform.GetComponent<RectTransform>();

            RectTransform transform = this.transform.parent as RectTransform;
            if (RectTransformUtility.ScreenPointToWorldPointInRectangle(transform, eventData.position, camera, out worldPosition))
            {
                // 在这里可以使用worldPosition，例如更新UI元素的位置
                transform.position = worldPosition;
            }
            this.transform.position = worldPosition + diss;
            // this.transform.position = worldPosition;

        }

        public void OnPointerDown(PointerEventData eventData)
        {
            //记录按下到中心点的偏移量坐标
            Vector2 vector2 = eventData.position; //鼠标屏幕坐标
            Camera came = eventData.pressEventCamera;
            Vector3 wporpositon;//鼠标世界坐标
            RectTransform rectTransform = this.transform.parent as RectTransform;
            RectTransformUtility.ScreenPointToWorldPointInRectangle(rectTransform, vector2, came, out wporpositon);
            diss = this.transform.position - wporpositon;
            //if (eventData.clickCount == 2)
            //{
            //    print(" PointerEventData double clicked ");
            //}
        }
    }
}

下面是实现判断拖拽的方向

public class gamacontrols : MonoBehaviour, IPointerDownHandler, IDragHandler
{
 
 #region  拖动参数
    //Vector3 disvec;
    Vector2 StartScreenPosition;
    MoveDirections dir = MoveDirections.wait;
    public bool IsDown = false;
    #endregion

    public void OnPointerDown(PointerEventData eventData)
    {
        //Vector2 vector2 = eventData.position;
        RectTransformUtility.ScreenPointToWorldPointInRectangle(rectTransform, vector2, came, out wporpositon);
        //RectTransform rectTransform = this.transform.parent as RectTransform;
        //Vector3 vecotrcurrent;
        //RectTransformUtility.ScreenPointToWorldPointInRectangle(rectTransform, vector2, eventData.pressEventCamera, out vecotrcurrent);
        //disvec = this.transform.position - vecotrcurrent;
        StartScreenPosition = eventData.position;
        IsDown = true;
    }
    public void OnDrag(PointerEventData eventData)
    {
        if (IsDown)
        {
            Vector2 Offset = eventData.position - StartScreenPosition;
            float x = MathF.Abs(Offset.x);
            float y = MathF.Abs(Offset.y);

            //执行左右移动
            if (x > y && x >= 50)
            {
                dir = Offset.x > 0 ? MoveDirections.right : MoveDirections.left;

            }
            //执行上下移动
            if (x < y && y >= 50)
            {
                dir = Offset.y > 0 ? MoveDirections.up : MoveDirections.dowm;
            }
            if (dir != MoveDirections.wait)
            {
                Core.Move(dir);
                dir = MoveDirections.wait;
                IsDown = false;
            }
        }
    }
}