AddLayer和AddTag

using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

public class LayerTagSpawn : AssetPostprocessor
{
    static void OnPostprocessAllAssets(string[] importedAssets, string[] deletedAssets, string[] movedAssets, string[] movedFromAssetPaths)
    {
        foreach (string s in importedAssets)
        {
            if (s.Contains("HandleController"))
            {
                AddLayer("dragLayer");
                AddLayer("terrain");
                return;
            }
        }
    }

    static void AddTag(string tag)
    {
        if (!isHasTag(tag))
        {
            SerializedObject tagManager = new SerializedObject(AssetDatabase.LoadAllAssetsAtPath("ProjectSettings/TagManager.asset")[0]);
            SerializedProperty it = tagManager.GetIterator();
            int index = 0;
            bool bFindTag = false;
            while (it.NextVisible(true))
            {
                if (it.name == "tags")
                {
                    for (int i = 0; i < it.arraySize; i++)
                    {
                        index++;
                        SerializedProperty dataPoint = it.GetArrayElementAtIndex(i);
                        if (string.IsNullOrEmpty(dataPoint.stringValue))
                        {
                            dataPoint.stringValue = tag;
                            tagManager.ApplyModifiedProperties();
                            bFindTag = true;
                            return;
                        }
                    }
                    if (!bFindTag)
                    {
                        it.InsertArrayElementAtIndex(index);
                        SerializedProperty property = it.GetArrayElementAtIndex(index);
                        property.stringValue = tag;
                        tagManager.ApplyModifiedProperties();
                        return;
                    }
                }
            }
        }
    }

    static void AddLayer(string layer)
    {
        if (!isHasLayer(layer))
        {
            SerializedObject tagManager = new SerializedObject(AssetDatabase.LoadAllAssetsAtPath("ProjectSettings/TagManager.asset")[0]);
            SerializedProperty it = tagManager.GetIterator();
            while (it.NextVisible(true))
            {
                if (it.name == "layers")
                {
                    for (int i = 8; i <= 31; i++)
                    {
                        SerializedProperty dataPoint = it.GetArrayElementAtIndex(i);
                        if (string.IsNullOrEmpty(dataPoint.stringValue))
                        {
                            dataPoint.stringValue = layer;
                            tagManager.ApplyModifiedProperties();
                            return;
                        }
                    }
                }
            }
        }
    }

    static bool isHasTag(string tag)
    {
        for (int i = 0; i < UnityEditorInternal.InternalEditorUtility.tags.Length; i++)
        {
            if (UnityEditorInternal.InternalEditorUtility.tags[i].Contains(tag))
                return true;
        }
        return false;
    }

    static bool isHasLayer(string layer)
    {
        for (int i = 0; i < UnityEditorInternal.InternalEditorUtility.layers.Length; i++)
        {
            if (UnityEditorInternal.InternalEditorUtility.layers[i].Contains(layer))
                return true;
        }
        return false;
    }
}