在项目开发中我们可以对诸如Layer、Tag等编辑器数据进行常量生成，来代替在代码中通过输入字符串生成常量的形式以提高开发效率。
Layer的生成可以通过LayerMask.LayerToName获取层名称（也可以从TagManager.asset中获得 ），Tag的生成可以手动将预制Tag标签写入常量列表，其他的自定义Tag可以从TagManager.asset中获得。
一、基本知识
1.unity预制Tag标签
TagManager.asset文件如下方所示。unity预制的Tag标签（如Respawn、Finish、EditorOnly等6个Tag）并没有在TagManager.asset文件中。
%YAML 1.1
%TAG !u! tag:unity3d.com,2011:
--- !u!78 &1
TagManager:serializedVersion: 2tags:- Testlayers:- Default- TransparentFX- Ignore Raycast- - Water- UI- TestLayer- - - - - - - - - - - - - - - - - - - - - - - - - m_SortingLayers:- name: DefaultuniqueID: 0locked: 0
2.Layer层
在Unity中，Layer机制是固定的，最多只能有32个Layer。这是由Unity的底层设计决定的，因为Layer是用一个32位的整型来表示的，每一位表示一个Layer。
二、工具
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Text;
using UnityEngine;public class LayerManager : MonoBehaviour
{// Start is called before the first frame updatevoid Start(){var sb = new StringBuilder(); //准备模板生成sb.AppendLine("public class _Const");sb.AppendLine("{");for (int i = 0; i < 32; i++) //遍历所有Layer{var name = LayerMask.LayerToName(i); //通过Unity的接口拿到Layer名称name = name.Replace(" ", "_").Replace("&", "_").Replace("/", "_").Replace(".", "_").Replace(",", "_").Replace(";", "_").Replace("%", "_").Replace("-", "_"); //对常见的特殊字符进行过滤Debug.Log(name);if (!string.IsNullOrEmpty(name))sb.AppendFormat("\tpublic const int LAYER_{0} = {1};\n", name.ToUpper(), i);}sb.AppendLine("\tpublic const string " + ("Tag_Untagged".ToUpper() + " = " + "\"Untagged\";"));sb.AppendLine("\tpublic const string " + ("Tag_Respawn".ToUpper() + " = " + "\"Respawn\";"));sb.AppendLine("\tpublic const string " + ("Tag_Finish".ToUpper() + " = " + "\"Finish\";"));sb.AppendLine("\tpublic const string " + ("Tag_EditorOnly".ToUpper() + " = " + "\"EditorOnly\";"));sb.AppendLine("\tpublic const string " + ("Tag_MainCamera".ToUpper() + " = " + "\"MainCamera\";"));sb.AppendLine("\tpublic const string " + ("Tag_Player".ToUpper() + " = " + "\"Player\";"));sb.AppendLine("\tpublic const string " + ("Tag_GameController".ToUpper() + " = " + "\"GameController\";")); //把一部分内置Tag先写死var asset = UnityEditor.AssetDatabase.LoadAllAssetsAtPath("ProjectSettings/TagManager.asset"); //取得自定义Tagif ((asset != null) && (asset.Length > 0)){Debug.Log(asset.Length);for (int i = 0; i < asset.Length; i++){//创建序列化对象var so = new UnityEditor.SerializedObject(asset[i]);var tags = so.FindProperty("tags"); //读取具体字段for (int j = 0; j < tags.arraySize; ++j){var item = tags.GetArrayElementAtIndex(j).stringValue;sb.AppendFormat("\tpublic const string TAG_{0} = \"{1}\";\n", item.ToUpper(), item);} //添加到模板//获取Layer的方法二// var layers = so.FindProperty("layers");// for (int j = 0; j < layers.arraySize; ++j)// {// var item = layers.GetArrayElementAtIndex(j).stringValue;// if (!string.IsNullOrEmpty(item))// sb.AppendFormat("\tpublic const int LAYER_{0} = {1};\n", item.ToUpper(), j);// }}}sb.AppendLine("}");File.WriteAllText("Assets/GeneratedConst.cs", sb.ToString()); //写入硬盘UnityEditor.AssetDatabase.Refresh(); //通知Unity刷新}}
三、生成的代码
public class _Const
{public const int LAYER_DEFAULT = 0;public const int LAYER_TRANSPARENTFX = 1;public const int LAYER_IGNORE_RAYCAST = 2;public const int LAYER_WATER = 4;public const int LAYER_UI = 5;public const int LAYER_TESTLAYER = 6;public const string TAG_UNTAGGED = "Untagged";public const string TAG_RESPAWN = "Respawn";public const string TAG_FINISH = "Finish";public const string TAG_EDITORONLY = "EditorOnly";public const string TAG_MAINCAMERA = "MainCamera";public const string TAG_PLAYER = "Player";public const string TAG_GAMECONTROLLER = "GameController";public const string TAG_TEST = "Test";
}