实现一个简单的背包功能（可以拖动物体，如果不属于有效范围会自动返回原来父物体的下面）
布局格式
BagPackUI是一个panel控件
BagGrid：空物体
bag_bg：背景
Item：物体需添加图1-2所示组件（Canvas Group组件）
当Blacks Raycasts=false时射线可以检测到下一层物体为true是不可以检测下一层
布局层次如图1-3所示
实现代码
管理类
using UnityEngine;
using System.Collections;
public class BagPackMgr : MonoBehaviour{
//tag标签的常量字符串
public const string groove = "groove";
public const string bagpackItem = "bagpackItem";
public const string bag = "bag";
Canvas GlobalCanvas;//画布
Transform BagGrid;//背包的道具父物体
//单件模式（单例模式）
static BagPackMgr Inst;
public static BagPackMgr Instance {
get {
return Inst;
}
}
void Awake() {
Inst = this;
GlobalCanvas = transform.parent.GetComponent();
BagGrid = transform.Find("BagGrid");
}
public Canvas getGlobalCanvas
{
get {
return GlobalCanvas;
}
}
public Transform GetBagGrid
{
get {
return BagGrid;
}
ItemDrag类
ItemDrag类
using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
using System;
public class ItemDrag : MonoBehaviour,IBeginDragHandler,IDragHandler,IEndDragHandler {
Transform _saveSelfParent;//保存自己的父物体
CanvasGroup _canvasGroup;//CanvasGroup组件
//鼠标点的那一帧执行
public void OnBeginDrag(PointerEventData eventData)
{
_canvasGroup = GetComponent();
_canvasGroup.blocksRaycasts = false;//不阻挡向下检测控件
_saveSelfParent = transform.parent;//将该物体的父物体保存在_saveSelfParent中
//设置父物体为画布Canvas
transform.SetParent(BagPackMgr.Instance.getGlobalCanvas.transform);
}
//拖动的过程中执行
public void OnDrag(PointerEventData eventData)
{
transform.position = eventData.position;//当下的位置赋给该物体（物体随鼠标移动）
}
//拖动结束时执行
public void OnEndDrag(PointerEventData eventData)
{
GameObject pointEenterobj = eventData.pointerEnter;
//空白出或外面，非响应区域
if (pointEenterobj == null)
{
transform.SetParent(_saveSelfParent);
transform.localPosition = Vector3.zero;
}
//拖动到了装备栏
else if (pointEenterobj.tag == BagPackMgr.groove)
{
transform.SetParent(pointEenterobj.transform);
transform.localPosition = Vector3.zero;
}
//拖到了道具上（交换位置）
else if (pointEenterobj.tag == BagPackMgr.bagpackItem)
{
transform.SetParent(pointEenterobj.transform.parent);
transform.localPosition = Vector3.zero;
pointEenterobj.transform.SetParent(_saveSelfParent);
pointEenterobj.transform.localPosition = Vector3.zero;
}
//卸下道具
else if (pointEenterobj.tag == BagPackMgr.bag)
{
transform.SetParent(BagPackMgr.Instance.GetBagGrid);
transform.localPosition = Vector3.zero;
}
//射线检测到了物体，但是不是我们逻辑需要的三种类型(无效操作)
else
{
transform.SetParent(_saveSelfParent);
transform.localPosition = Vector3.zero;
}
//重置射线检测
_canvasGroup.blocksRaycasts = true;
}