[Unity] Generate constants class from Assets/Resouces Directory.

GenerateResourceNames.cs

using UnityEngine;
using UnityEditor;
using System.IO;

// Put this file to under the Assets/Editor
public class GenerateResourceNames : EditorWindow {

	[MenuItem("Edit/Generate ResourceNames.cs")]
	private static void GenerateFile() {

		if (!Directory.Exists ("./Assets/Scripts")) {
			Directory.CreateDirectory ("./Assets/Scripts");
		}

		if (File.Exists ("./Assets/Scripts/ResourceNames.cs")) {
			File.Delete ("./Assets/Scripts/ResourceNames.cs");
		}

		if (Directory.Exists ("./Assets/Resources")) {
			using (StreamWriter writer = File.CreateText ("./Assets/Scripts/ResourceNames.cs")) {
				writeResourceDir (writer, "ResourceNames", "./Assets/Resources", 0);
			}
		}

		Debug.Log ("Generate File : Scripts/ResourceNames.cs");
	}

	private static void writeResourceDir(StreamWriter writer, string dir, string path, int deep) {

		writer.WriteLine (getIndentStr (deep) + "public static class " + dir + " {");
		string[] subDirs = Directory.GetDirectories (path);
		foreach (string subDir in subDirs) {
			string dirName = Path.GetFileName (subDir);
			if (dirName.StartsWith (".")) {
				continue;
			}
			writeResourceDir (writer, dirName, subDir, deep + 1);
		}

		string[] files = Directory.GetFiles (path);
		foreach (string file in files) {
			if (Path.GetFileName (file).StartsWith (".") || file.EndsWith (".meta")) {
				continue;
			}
			writeResourceFile (writer, file, deep + 1);
		}
		writer.WriteLine (getIndentStr (deep) + "}");
	}

	private static void writeResourceFile(StreamWriter writer, string file, int deep) {
		string fileName = Path.GetFileNameWithoutExtension (file);
		fileName = System.Text.RegularExpressions.Regex.Replace (fileName, "[^a-zA-Z0-9_]", "");

		string resourcePath = file.Substring ("./Assets/Resources/".Length);
		string resourceFile = Path.Combine (Path.GetDirectoryName (resourcePath), Path.GetFileNameWithoutExtension (resourcePath));

		writer.WriteLine (getIndentStr (deep) + "public const string " + fileName + " = \"" + resourceFile + "\";");
	}

	private static string getIndentStr(int deep) {
		return "".PadRight (deep * 4);
	}
}