ScrollView 最优使用方案

Purpose:
ScrollView 一直是UI界面最费的地方，这里的解决方案可谓是集对象池，自定义各种效果等之大乘。代码很长，但有demo可以观摩。不足之处，多多赐教。
这个小插件的借助了 Grid Layout Group组件的各个参数，利用拖动事件驱动所有的滑动效果。
自动控制ScrollView下的Item对象，
利用对象池技术，最优化实现滚动显示信息的功能。
详细使用方法请看源代码。
Author:
赵光辉
Data:
2016/11/20

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

/// 

/// 控制类
/// 
public class ScrollRectAutoItem : MonoBehaviour, IEndDragHandler, IDragHandler
{
    /// 

    /// 拖拽事件回调
    /// 
    public Action OnDragBack;

    /// 

    /// 拖拽事件回调
    /// 
    public Action OnEndDragBack;

    /// 

    /// 滚动事件回调
    /// 
    public Action ScrollItemBack;

    /// 

    /// Item控制模式
    /// 
    public ItemState ItemState = ItemState.RollItem;

    /// 

    /// 组件
    /// 
    private ScrollRect customScrollRect;

    private RectTransform content;
    private GridLayoutGroup gridLayoutGroup;

    /// 

    /// item预置物
    /// 
    private GameObject itemUnit;

    /// 

    /// item预置物路径
    /// 
    private string itemUnitPath;

    /// 

    /// Item对象池
    /// 
    private GameObject pool;

    /// 

    /// 当前滑动的区域id
    /// 
    private float itemIdFloatDown = 0;

    private float itemIdFloatUp = 0;
    private int itemIdIntDown = 0;
    private int itemIdIntUp = 0;

    /// 

    /// customScrollRect数据
    /// 
    private Vector2 sizeDelta;

    /// 

    /// content数据
    /// 
    private Vector3 contentLocalPos;

    /// 

    /// GridLayoutGroup数据
    /// 
    private int constraintCount = 0;

    private Vector2 cellSize = Vector2.zero;
    private Vector2 spacing = Vector2.zero;
    private RectOffset padding;

    /// 

    /// 子对象个数
    /// 
    private int childCount;

    /// 

    /// 子对象行数或者列数
    /// 
    private int rowOrColNum;

    /// 

    /// 每一个item的位置
    /// 
    private Dictionary itemPosDic;

    /// 

    /// 维护子对象的使用
    /// 
    private Stack itemStack;

    /// 

    /// item信息类
    /// 
    private Type handlerInfo;

    /// 

    /// 参数
    /// 
    private List