今天做一个拖动图像的demo，效果图如下：

 

1 拖动的类需要实现 IDropHandler, IPointerEnterHandler, IPointerExitHandler 这三个接口；

2 接受的类需要实现 IBeginDragHandler,IDragHandler,IEndDragHandler 这三个接口：

下面贴代码

Drag.cs

using UnityEngine;using UnityEngine.EventSystems;using UnityEngine.UI;//拖动要集成三个接口：IBeginDragHandler,IDragHandler,IEndDragHandler[RequireComponent(typeof(Image))]public class Drag : MonoBehaviour,IBeginDragHandler,IDragHandler,IEndDragHandler {    //是否与面板保持平行    public bool dragOnSurfaces = true;    private GameObject m_DragIcon;    private RectTransform m_RectPlane;    public void OnBeginDrag(PointerEventData eventData)    {        var canvas = FindInParent
     
      (gameObject);        if (canvas == null) return;        //创建临时拖动对象名为“Icon”        m_DragIcon = new GameObject("Icon");        //为拖动对象设置画布        m_DragIcon.transform.SetParent(canvas.transform, false);        //设置为同级最后        m_DragIcon.transform.SetAsLastSibling();        var image = m_DragIcon.AddComponent
      ();        //拖动对象忽略事件响应        m_DragIcon.AddComponent
      
       ();        image.sprite = gameObject.GetComponent
       ().sprite;        image.SetNativeSize();        if (dragOnSurfaces)            m_RectPlane = transform as RectTransform;        else            m_RectPlane = canvas.transform as RectTransform;                //拖动对象跟随光标        SetDraggedPosition(eventData);    }    public void OnDrag(PointerEventData eventData)    {        if (m_DragIcon != null)            SetDraggedPosition(eventData);    }    private void SetDraggedPosition(PointerEventData data)    {        if (dragOnSurfaces && data.pointerEnter != null && data.pointerEnter.transform as RectTransform != null)            m_RectPlane = data.pointerEnter.transform as RectTransform;        var rt = m_DragIcon.GetComponent
       
        ();        // 屏幕点在矩形内的世界坐标        Vector3 globalMousePos;        if (RectTransformUtility.ScreenPointToWorldPointInRectangle(m_RectPlane,data.position,data.pressEventCamera,out globalMousePos))        {            rt.position = globalMousePos;            rt.rotation = m_RectPlane.rotation;        }    }    public void OnEndDrag(PointerEventData eventData)    {        //释放删除临时对象        if (m_DragIcon != null)            Destroy(m_DragIcon);    }    static public T FindInParent
        
         (GameObject go) where T:Component    {        if (go == null) return null;        var comp = go.GetComponent
         
          ();        if (comp != null)            return comp;        Transform temp = go.transform.parent;        while (temp != null && comp == null)        {            comp = temp.gameObject.GetComponent
          
           (); if (comp != null) return comp; temp = temp.parent; } return comp; }}
          
         
        
       
      
     

 

Drop.cs

using UnityEngine;using UnityEngine.EventSystems;using UnityEngine.UI;//接收拖动的类需要实现的三个接口：IDropHandler, IPointerEnterHandler, IPointerExitHandlerpublic class Drop : MonoBehaviour, IDropHandler, IPointerEnterHandler, IPointerExitHandler{    public Image containerImage;    public Image receivingImage;    private Color normalColor;    public Color highLightColor = Color.blue;    public void OnEnable()    {        if (containerImage != null)            normalColor = containerImage.color;    }    //释放对象    public void OnDrop(PointerEventData eventData)    {        containerImage.color = normalColor;        //没有图像直接返回        if (receivingImage == null)            return;        Sprite dropSprite = GetDropSprite(eventData);        if (dropSprite != null)            receivingImage.sprite = dropSprite;    }    //对象移到接受面板，面板高亮    public void OnPointerEnter(PointerEventData eventData)    {        if (containerImage == null)            return;        Sprite dropSprite = GetDropSprite(eventData);        if (dropSprite != null)            containerImage.color = highLightColor;    }    public void OnPointerExit(PointerEventData eventData)    {        if (containerImage == null)            return;        containerImage.color = normalColor;    }    //获取图像数据    private Sprite GetDropSprite(PointerEventData data)    {        var originalObj = data.pointerDrag;        if (originalObj == null)            return null;        var srcImage = originalObj.GetComponent();        if (srcImage == null)            return null;        return srcImage.sprite;    }}

 

demo源文件