Unity中UGUI 图片实现鼠标拖拽功能以及松开复位_unity ui 拖拽

应用方法：将下面脚本挂载在需要拖拽功能的UI图片上即可

两种拖拽选择：A.中心拖拽（图片中心跟随鼠标位置）m_isPrecision为false；

B.精准拖拽（图片被鼠标点击的位置跟随鼠标位置）m_isPrecision为true；
　　　　　　　
常用的代码和主要实现方式都贴在下面了；

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
using DG.Tweening;

//UI图片拖拽功能类
public class UIDragBySSW : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler,IPointerEnterHandler, IPointerExitHandler
{
    public ModelCon MC;
    [Header("是否精准拖拽")]
    public bool m_isPrecision;

    //存储图片中心点与鼠标点击点的偏移量
    private Vector3 m_offset;

    //存储当前拖拽图片的RectTransform组件
    private RectTransform m_rt;
    private Vector3 imgPos;
    private Vector3 imgscale;
    void Start()
    {

        //初始化
        m_rt = gameObject.GetComponent<RectTransform>();
        imgPos = m_rt.anchoredPosition3D;
        imgscale = m_rt.localScale;
    }

    //开始拖拽触发
    public void OnBeginDrag(PointerEventData eventData)
    {
        //如果精确拖拽则进行计算偏移量操作
        if (m_isPrecision)
        {
            // 存储点击时的鼠标坐标
            Vector3 tWorldPos;
            //UI屏幕坐标转换为世界坐标
            RectTransformUtility.ScreenPointToWorldPointInRectangle(m_rt, eventData.position, eventData.pressEventCamera, out tWorldPos);
            //计算偏移量   
            m_offset = transform.position - tWorldPos;
        }
        //否则，默认偏移量为0
        else
        {
            m_offset = Vector3.zero;
        }

        SetDraggedPosition(eventData);
    }

    //拖拽过程中触发
    public void OnDrag(PointerEventData eventData)
    {

        SetDraggedPosition(eventData);
    }

    //结束拖拽触发
    public void OnEndDrag(PointerEventData eventData)
    {

        SetDraggedPosition(eventData);
        //采用DoTween的方式  松开鼠标自动复位
        m_rt.DOAnchorPos3D(imgPos,0.4f);![请添加图片描述](https://img-blog.csdnimg.cn/direct/808c85df37544843bed7b1a6ae4ac79f.gif)

    }

    /// <summary>
    /// 设置图片位置方法
    /// </summary>
    /// <param name="eventData"></param>
    private void SetDraggedPosition(PointerEventData eventData)
    {
        //存储当前鼠标所在位置
        Vector3 globalMousePos;
        //UI屏幕坐标转换为世界坐标
        if (RectTransformUtility.ScreenPointToWorldPointInRectangle(m_rt, eventData.position, eventData.pressEventCamera, out globalMousePos))
        {
            //设置位置及偏移量
            m_rt.position = globalMousePos + m_offset;
        }
    }

//在这里做了一个鼠标进入时的动态效果
    public void OnPointerEnter(PointerEventData eventData)
    {
        m_rt.localScale = new Vector3(imgscale.x*1.1f, imgscale.y * 1.1f, 1);    }

    public void OnPointerExit(PointerEventData eventData)
    {
        m_rt.localScale = imgscale;
    }
}
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通过鼠标拖拽小按钮 配合其他方法可以做一些动态的变换效果；

 EventTriggerListener.Get(UiPanel).onClick+= (go) =>
        {
            Debug.Log("UI按钮按下========="+go.name);
        };
        EventTriggerListener.Get(UiPanel).onUp+= (go) =>
        {
        	//中间大图标效果变换
          Debug.Log("UI按钮抬起========="+go.name);.
          
        };
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using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
public class EventTriggerListener : UnityEngine.EventSystems.EventTrigger
{
    public delegate void VoidDelegate(GameObject go);
    public VoidDelegate onClick;
    public VoidDelegate onDown;
    public VoidDelegate onEnter;
    public VoidDelegate onExit;
    public VoidDelegate onUp;
    public VoidDelegate onSelect;
    public VoidDelegate onUpdateSelect;
    public VoidDelegate onEndDrag;

    static public EventTriggerListener Get(GameObject go)
    {
        EventTriggerListener listener = go.GetComponent<EventTriggerListener>();
        if (listener == null) listener = go.AddComponent<EventTriggerListener>();
        return listener;
    }
    public override void OnPointerClick(PointerEventData eventData)
    {
        if (onClick != null) onClick(gameObject);
    }
    public override void OnPointerDown(PointerEventData eventData)
    {
        if (onDown != null) onDown(gameObject);
    }
    public override void OnPointerEnter(PointerEventData eventData)
    {
        if (onEnter != null) onEnter(gameObject);
    }
    public override void OnPointerExit(PointerEventData eventData)
    {
        if (onExit != null) onExit(gameObject);
    }
    public override void OnPointerUp(PointerEventData eventData)
    {
        if (onUp != null) onUp(gameObject);
    }
    public override void OnSelect(BaseEventData eventData)
    {
        if (onSelect != null) onSelect(gameObject);
    }
    public override void OnUpdateSelected(BaseEventData eventData)
    {
        if (onUpdateSelect != null) onUpdateSelect(gameObject);
    }

    public override void OnEndDrag(PointerEventData eventData)
    {
        base.OnEndDrag(eventData);
        if (onEndDrag != null) onEndDrag(gameObject);
    }
}
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