Demon_背包系统(实现装备栏，背包栏，可以切换装备)

using UnityEngine;
using System.Collections;

public enum BoxType
{
    Normal,//普通格子
    Equip//装备栏格子
}
    
public enum EquipType
{
    Weapon,//武器
    Armor,//护甲
    Shoot//鞋子
}

public class Box : MonoBehaviour {

    //格子类型
    public BoxType boxType;
    //装备类型
    public EquipType equipType;
    //格子的子对象（一些装备）
    public Transform child;

    void Start()
    {
        //给子对象赋值
        if (transform.childCount == 1) {
            child = transform.GetChild (0);
        }
    }

    /// <summary>
    /// 接收物品
    /// </summary>
    /// <param name="goods">Goods.</param>
    public void ReceiveGoods(Goods goods)
    {
        //普通格子
//        if (boxType == BoxType.Normal) {
//            BagSingleton.instance.SetParent (goods.transform, transform);
//        } else {
//            //如果装备类型匹配
//            if (goods.goodsType == equipType) {
//                BagSingleton.instance.SetParent (goods.transform, transform);
//            } else {
//                //不匹配返回
//                goods.ReturnBack ();
//            }
//        }


        //优化版
        if (boxType == BoxType.Equip && goods.goodsType != equipType) {
            goods.ReturnBack ();
        } else {
            BagSingleton.instance.SetParent (goods.transform, transform);
            //更新物品的父物体
            goods.parent = transform;
            //更新格子的子物体
            child = goods.transform;
        }
    }
}

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

public class Goods : MonoBehaviour,
IBeginDragHandler,IDragHandler,IEndDragHandler {

    //物品类型
    public EquipType goodsType;
    //父对象（格子）
    public Transform parent;

    private CanvasGroup canvasGroup;

    void Start()
    {
        //给父对象赋值
        if (transform.parent) {
            parent = transform.parent;
        }
        //获取
        canvasGroup = GetComponent<CanvasGroup> ();
    }

    public void OnBeginDrag (PointerEventData eventData)
    {
        //将物品移除格子
        transform.SetParent (BagSingleton.instance.bag);
        //关闭阻挡射线
        canvasGroup.blocksRaycasts = false;
    }

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

    public void OnEndDrag (PointerEventData eventData)
    {
        //如果当前物品下方有对象
        if (eventData.pointerEnter) {
            //获取底层对象标签
            string tag = eventData.pointerEnter.tag;
            //如果是格子
            if (tag == "Box") {
                //接收物品
                eventData.pointerEnter.
                    GetComponent<Box> ().ReceiveGoods (this);
            }
            //如果是物品
            else if (tag == "Goods") {
                //下面物品
                Goods herGoods = eventData.pointerEnter.GetComponent<Goods> ();
                //下面物品所在格子
                Box herBox = herGoods.parent.GetComponent<Box>();
                //当前物品
                Goods myGoods = this;
                //当前物品所在格子
                Box myBox = parent.GetComponent<Box>();
                //交换
                BagSingleton.instance.GoodsExchange (myBox, myGoods, herBox, herGoods);
            }
            //其他
            else {
                //返回
                ReturnBack ();
            }
        } else {
            //返回
            ReturnBack ();
        }

        //开启阻挡射线
        canvasGroup.blocksRaycasts = true;
    }

    /// <summary>
    /// 返回原单位
    /// </summary>
    public void ReturnBack()
    {
        BagSingleton.instance.SetParent (transform, parent);
    }
}

using UnityEngine;
using System.Collections;

public class BagSingleton : MonoBehaviour {

    //单例
    public static BagSingleton instance;

    //背包
    public Transform bag;

    void Start()
    {
        instance = this;

        bag = GameObject.FindWithTag ("Bag").transform;
    }

    /// <summary>
    /// 设置格子父物体，并与父物体位置保持同步
    /// </summary>
    /// <param name="parent">Parent.</param>
    public void SetParent(Transform son ,Transform parent)
    {
        son.SetParent (parent);
        son.localPosition = Vector3.zero;
    }

    /// <summary>
    /// 物品交换
    /// </summary>
    /// <param name="myBox">My box.</param>
    /// <param name="myGoods">My goods.</param>
    /// <param name="herBox">Her box.</param>
    /// <param name="herGoods">Her goods.</param>
    public void GoodsExchange(Box myBox,Goods myGoods,Box herBox,Goods herGoods)
    {
        //如果双方都在普通格子中，或，双方物品类型一致
        if ((myBox.boxType == BoxType.Normal &&
            herBox.boxType == BoxType.Normal)
            || (myGoods.goodsType == herGoods.goodsType)) {
            myBox.ReceiveGoods (herGoods);
            herBox.ReceiveGoods (myGoods);
        } else {
            //当前物品返回原单位
            myGoods.ReturnBack ();
        }
    }
}

BagSingleton是Box跟goods两个脚本会引用的单例脚本判断物品切换