NGUI討論群：333417608

解決的問題

使用grid放置item的時候，每次資料可能都不一樣，但是每次都刪除grid下面的節點，之後動態建立新的item是比較浪費的。

寫個簡單的工具函式，原理很簡單。

1、先獲得grid下面的可用item

2、根據data的大小進行初始化

3、每次在可用的item列表裡面獲取新的item，如果不夠用了，就建立新的item

4、disable掉沒用的item

附：每個grid下面預先要有一個名字包含“Template_”的模板item。這個模板不會被用，之前嘗試過把這個模板也當做一個item正常使用，但是有些NGUI的widget會出現BUG。

using UnityEngine;
using System.Collections.Generic;
//qq group :333417608
public class UITools
{
	
	/* usage:
		List<GameObject> canUseList = UITools.GetCanUseItemList(gridRoot);
		for (int i=0; i<totalData.Length; ++i)
		{
			GameObject go = UITools.GetNewItemObj(canUseList, gridRoot, prefab);
			// do init
		}
		UITools.UnActiveUnuseItem(canUseList);

		// prefab is the template
	 */ 

	static public GameObject GetNewItemObj (List<GameObject> canUseList, GameObject root, GameObject prefab)
	{
		GameObject go = null;
		if (canUseList.Count > 0) {
			go = canUseList [0];
			canUseList.RemoveAt (0);
		} else {
			go = NGUITools.AddChild (root, prefab);
		}
		NGUITools.SetActiveSelf (go, true);
		return go;
	}
	
	static public T GetNewItemObj<T> (List<T> canUseList, GameObject root, GameObject prefab) where T : Component
	{
		T item = null;
		if (canUseList.Count > 0) {
			item = canUseList [0];
			canUseList.RemoveAt (0);
		} else {
			item = NGUITools.AddChild (root, prefab).GetComponent<T>();
		}
		item.name = string.Format("{0:D3}", 0);
		NGUITools.SetActiveSelf (item.gameObject, true);
		return item;
	}
	
	static public List<GameObject> GetCanUseItemList (GameObject root)
	{
		List<GameObject> itemList = new List<GameObject> ();
		Transform rootT = root.transform;
		for (int i=0; i<rootT.childCount; ++i) {
			GameObject go = rootT.GetChild (i).gameObject;
			if (IsNotTemplateGameObject(go))
			{
				itemList.Add (go);
			}
		}
		return itemList;
	}
	
	static public List<T> GetCanUseItemList<T> (GameObject root) where T : Component
	{
		List<T> childrenList = new List<T> ();
		Transform rootT = root.transform;
		for (int i=0; i<rootT.childCount; ++i) {
			Transform child = rootT.GetChild (i);
			T t = child.GetComponent<T> ();
			if (t != null && IsNotTemplateGameObject(child.gameObject)) {
				childrenList.Add (t);
			}
		}
		return childrenList;
	}
	
	static public void UnActiveUnuseItem (List<GameObject> canUseList)
	{
		foreach (var item in canUseList) {
			NGUITools.SetActiveSelf (item, false);
		}
	}
	
	static public void UnActiveUnuseItem<T> (List<T> canUseList) where T : Component
	{
		foreach (var item in canUseList) {
			NGUITools.SetActiveSelf (item.gameObject, false);
		}
	}
	
	static private bool IsNotTemplateGameObject(GameObject go)
	{
		bool result = !go.name.ToLower().Contains("template_");
		if (!result && go.activeSelf)
		{
			NGUITools.SetActiveSelf(go, false);
		}
		return result;
	}
}