Question

我目前正在尝试创建一个拖放系统，其中有一个可拖动的UI对象，可以将其放置在另一个对象上。但是我不知道如何将UI对象放在鼠标和可拖动UI对象的下方。

这是我的dragableObject的代码：

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DragHandeler : MonoBehaviour, IBeginDragHandler, IDragHandler, 
IEndDragHandler
{
  public Transform parentToReturnTo = null;
  public Transform placeHolderParent = null;


  public void OnBeginDrag(PointerEventData eventData)
  {
      parentToReturnTo = transform.parent;
  }

  public void OnDrag(PointerEventData eventData)
  {
      transform.position = eventData.position;

  }

  public void OnEndDrag(PointerEventData eventData)
  {
      transform.position = parentToReturnTo.position;
  }
}

以及此代码用于我的占位符：

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.EventSystems;
 public class PlaceHolder : MonoBehaviour, IDropHandler, 
 IPointerEnterHandler, IPointerExitHandler
 {
    public void OnPointerEnter(PointerEventData eventData)
    {
         Transform test = eventData.pointerDrag.GetComponent<Transform>();
        Debug.Log(test.name);
    }

    public void OnPointerExit(PointerEventData eventData)
    {
    }

    public void OnDrop(PointerEventData eventData)
   {
   }
}

问题在于OnPointerEnter函数并非总是在应有的时候被调用，它仅在我用鼠标悬停在对象上方时才调用它。关于如何使当前对象位于可拖动对象下方，是否还有其他方法？

Answer 1

因此，问题是您的“可拖动对象”阻止了该对象其后的所有对象的光线投射，结果-您的PlaceHolder不会触发任何事件，因为光线始终被阻止被你的“拖拉”。最简单的解决方案是在拖动开始时禁用 raycastTarget 属性，然后在拖动结束时重新启用它。

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DragHandeler : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
  public Transform parentToReturnTo = null;
  public Transform placeHolderParent = null;

  public void OnBeginDrag(PointerEventData eventData)
  {
      // disable 'raycast target' for your draggable object
      GetComponent<Image>().raycastTarget = false;

      parentToReturnTo = transform.parent;
  }

  public void OnDrag(PointerEventData eventData)
  {
      transform.position = eventData.position;
  }

  public void OnEndDrag(PointerEventData eventData)
  {
      // enable it back when drag is over
      GetComponent<Image>().raycastTarget = true;

      transform.position = parentToReturnTo.position;
  }
}

如何在Unity中的鼠标下方获取UI对象？

1 个答案: