使用垃圾桶创建拖放系统以删除对象

Question

我在创建允许将游戏对象拖放到屏幕的垃圾区域从而破坏游戏对象的脚本时遇到问题。我在 onDrop 函数中哪里出错了？基本上我想说的是，当一个游戏对象被扔到垃圾桶上时，它就变成了垃圾桶的一个孩子，一旦它成为一个孩子，它就会被摧毁。这个逻辑有意义吗？

using System.Collections;
using UnityEngine.EventSystems;

namespace MyNamespace
{
    public class DropZone : MonoBehaviour, IDropHandler, IPointerEnterHandler, IPointerExitHandler 
    {
        public void OnPointerEnter(PointerEventData eventData)
        {
            if(eventData.pointerDrag == null)
                return;

            DragHandling dragHandling = eventData.pointerDrag.GetComponent<DragHandling>();

            if(dragHandling != null)
            {
                dragHandling.placeholderParent = this.transform;        // change parent based on drop zone
            } 
        }

    public void OnPointerExit(PointerEventData eventData)
    {
        if(eventData.pointerDrag == null)
            return;

        DragHandling dragHandling = eventData.pointerDrag.GetComponent<DragHandling>();
        if(dragHandling != null && dragHandling.placeholderParent == this.transform)
        {
            dragHandling.placeholderParent = dragHandling.parentToReturnTo;     // change parent based on drop zone
        } 
    }

    public void OnDrop(PointerEventData eventData)
    {
        Debug.Log(eventData.pointerDrag.name + " was dropped on " + gameObject.name);

        DragHandling dragHandling = eventData.pointerDrag.GetComponent<DragHandling>();

        if(dragHandling != null)
        {
            dragHandling.parentToReturnTo = this.transform;     // change parent based on drop zone
        }  

        if (this.transform.parent.gameObject == dragHandling.trashCan) 
        {
            Destroy(this);
        }
    }
}

这是我用来获取变量的脚本：

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

public class DragHandling : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler, IPointerClickHandler
{
    public Transform placeholderParent = null;
    public Transform parentToReturnTo = null;

    GameObject placeholder = null;

    public GameObject trashCan;
    public Transform trashCanTrans;
    public GameObject partsPanel;
    public Transform partsPanelTrans;
    public GameObject buildBoard;
    public GameObject dragLayer;

    void Awake ()
    {
        dragLayer = GameObject.FindGameObjectWithTag("DragLayer");
        buildBoard = GameObject.FindGameObjectWithTag("Board");
        partsPanel = GameObject.FindGameObjectWithTag("Parts");
        trashCan = GameObject.FindGameObjectWithTag("Trash");

        partsPanelTrans = partsPanel.transform;
        // trashCanTrans = trashCan.transform;
    }

    #region IPointerClickHandler implementation

    public void OnPointerClick (PointerEventData eventData)
    {
        if(this.transform.parent.gameObject == buildBoard)
        {
            this.transform.SetAsLastSibling();
        }

    }

    #endregion

    #region IBeginDragHandler implementation

    public void OnBeginDrag (PointerEventData eventData)
    {
        // this.transform.SetAsLastSibling();

        // create placeholder gap and hold correct position in layout
        placeholder = new GameObject();
        placeholder.transform.SetParent(this.transform.parent);
        placeholder.transform.SetSiblingIndex(this.transform.GetSiblingIndex());

        LayoutElement le = placeholder.AddComponent<LayoutElement>();               // add layout element

        le.preferredWidth = this.GetComponent<LayoutElement>().preferredWidth;      
        le.preferredHeight = this.GetComponent<LayoutElement>().preferredHeight;
        le.flexibleWidth = 0;
        le.flexibleHeight = 0;

        parentToReturnTo = this.transform.parent;                   // store current parent location
        placeholderParent = parentToReturnTo;                       // set placeholder gameobject transform

        GetComponent<CanvasGroup>().blocksRaycasts = false;         // turn off image raycasting when dragging image in order to see what's behind the image            
    }

    #endregion

    #region IDragHandler implementation

    public void OnDrag (PointerEventData eventData)
    {
        this.transform.position = eventData.position;               // set object coordinates to mouse coordinates
        this.transform.SetParent(dragLayer.transform);              // pop object to draglayer to move between dropzones
    }

    #endregion

    #region IEndDragHandler implementation

    public void OnEndDrag (PointerEventData eventData)
    {
        this.transform.SetParent(parentToReturnTo);                                 // Snaps object back to orginal parent if dropped outside of a dropzone
        this.transform.SetSiblingIndex(placeholder.transform.GetSiblingIndex());    // Returns card back to placeholder location

        GetComponent<CanvasGroup>().blocksRaycasts = true;                          // turn on Raycast blocking

        Destroy(placeholder);                                                       // kill the placeholder if object hits a drop zone or returns to parts panel
    }

    #endregion
}

好的，所以我做了一些更改，现在当我将游戏对象拖到垃圾箱上时，它会被破坏，但垃圾箱也是如此。我一直试图让它工作，但仍然没有运气。这是我现在所拥有的，但它仍然无法正常工作。

public void OnDrop(PointerEventData eventData) { Debug.Log(eventData.pointerDrag.name + " 被丢弃在 " + gameObject.name);

    DragHandling dragHandling = eventData.pointerDrag.GetComponent<DragHandling>();

    if(dragHandling != null)
    {
        dragHandling.parentToReturnTo = this.transform;     // change parent based on drop zone

        if (this.transform.gameObject == dragHandling.trashCan) 
        {
            Debug.Log("You've dragged something into the trash!");

            Destroy(this.transform.gameObject);
        }
    }  
}

Answer 1

如果垃圾可以与游戏对象一起销毁，请不要使该对象成为垃圾箱的子对象。这里可能发生的情况是，destroy() 函数还想销毁对象的父对象，以保持数据的一致性。

Answer 2

老实说，我认为您不应该将“this”放入destroy函数中，请参阅直接提问的人：http://answers.unity3d.com/questions/19223/is-destroygameobject-the-same-as-destroythis.html

您试图破坏放置区而不是破坏游戏对象。只销毁游戏对象，一切都应该没问题。