Selectable Enumeration

EnumDescriptionAttribute.cs

using System;
using System.ComponentModel;
using UnityEngine;
using System.Reflection;

namespace JFun.Gameplay.CreateWorld
{
	[AttributeUsage(AttributeTargets.Field)]
	public class EnumDescriptionAttribute : PropertyAttribute
	{
	}

	public static class EnumExt
	{
		public static string GetDescription(this Enum value)
		{
			FieldInfo fi = value.GetType().GetField(value.ToString());
			DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
			return attributes.Length > 0 ? attributes[0].Description : value.ToString();
		}

		public static Enum Next(this Enum value)
		{
			Array valuerange = Enum.GetValues(value.GetType());
			int index = Array.IndexOf(valuerange, value);
			index++;
			return (Enum)valuerange.GetValue(index < valuerange.Length ? index : valuerange.Length - 1) ;
		}

		public static Enum Previous(this Enum value)
		{
			Array valuerange = Enum.GetValues(value.GetType());
			int index = Array.IndexOf(valuerange, value);
			index--;
			return (Enum)valuerange.GetValue(index >= 0 ? index : 0);
		}
	}
}

EnumDescriptionPropertyDrawer.cs

using UnityEditor;
using UnityEngine;
using System;
using System.Reflection;
using JFun.Gameplay.CreateWorld.UI;

namespace JFun.Gameplay.CreateWorld
{
	[CustomPropertyDrawer(typeof(EnumDescriptionAttribute), true)]
	public class ShowReadOnlyDescriptionDrawer : PropertyDrawer
	{
		public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
		{
			var height = EditorGUI.GetPropertyHeight(property, label, true);
			if (property.propertyType == SerializedPropertyType.Enum)
				height *= 2;
			return height;
		}

		public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
		{

			//if (property.propertyType == SerializedPropertyType.Enum)
			{
				Enum targetEnum = (Enum)Enum.ToObject(fieldInfo.FieldType, property.intValue);

				Enum enumNew = EditorGUI.EnumPopup(position, label.text, targetEnum);
				property.enumValueIndex =
					(int)Convert.ChangeType(enumNew, targetEnum.GetType());

				var height = position.height / 2;
				position.y += height;
				position.height = height;

				//GUI.enabled = false;
				EditorGUI.BeginDisabledGroup(true);
				EditorGUI.LabelField(position, "Description", enumNew.GetDescription(), GUIStyle.none);
				EditorGUI.EndDisabledGroup();
				//GUI.enabled = true;
			}

		}
	}
}