CrowdControl/Assets/Feel/MMTools/Editor/MMAttributes/MMDropdownAttributeDrawer.cs

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

namespace MoreMountains.Tools
{
	[CustomPropertyDrawer(typeof(MMDropdownAttribute))]
	public class MMDropdownAttributeDrawer : PropertyDrawer
	{        
		protected MMDropdownAttribute _dropdownAttribute;
		protected string[] _dropdownValues;
		protected int _selectedDropdownValueIndex = -1;
		protected Type _propertyType;
        
		#if  UNITY_EDITOR
		public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
		{
			if (_dropdownAttribute == null)
			{
				_dropdownAttribute = (MMDropdownAttribute)attribute;
				if (_dropdownAttribute.DropdownValues == null || _dropdownAttribute.DropdownValues.Length == 0)
				{
					return;
				}

				_propertyType = _dropdownAttribute.DropdownValues[0].GetType();
                
				_dropdownValues = new string[_dropdownAttribute.DropdownValues.Length];
				for (int i = 0; i < _dropdownAttribute.DropdownValues.Length; i++)
				{
					_dropdownValues[i] = _dropdownAttribute.DropdownValues[i].ToString();
				}

				bool found = false;
				for (var i = 0; i < _dropdownValues.Length; i++)
				{
					if ((_propertyType == typeof(string)) && property.stringValue == _dropdownValues[i])
					{
						_selectedDropdownValueIndex = i;
						found = true;
						break;
					}
					if ((_propertyType == typeof(int)) && property.intValue == Convert.ToInt32(_dropdownValues[i]))
					{
						_selectedDropdownValueIndex = i;
						found = true;
						break;
					}
					if ((_propertyType == typeof(float)) && Mathf.Approximately(property.floatValue, Convert.ToSingle(_dropdownValues[i])))
					{
						_selectedDropdownValueIndex = i;
						found = true;
						break;
					}
				}
				if (!found)
				{
					_selectedDropdownValueIndex = 0;
				}
			}

			if ((_dropdownValues == null) || (_dropdownValues.Length == 0) || (_selectedDropdownValueIndex < 0))
			{
				EditorGUI.PropertyField(position, property, label);
				return;
			}

			EditorGUI.BeginChangeCheck();
			_selectedDropdownValueIndex = EditorGUI.Popup(position, label.text, _selectedDropdownValueIndex, _dropdownValues);
			if (EditorGUI.EndChangeCheck())
			{
				if (_propertyType == typeof(string))
				{
					property.stringValue = _dropdownValues[_selectedDropdownValueIndex];
				}
				else if (_propertyType == typeof(int))
				{
					property.intValue = Convert.ToInt32(_dropdownValues[_selectedDropdownValueIndex]);
				}
				else if (_propertyType == typeof(float))
				{
					property.floatValue = Convert.ToSingle(_dropdownValues[_selectedDropdownValueIndex]);
				}
				property.serializedObject.ApplyModifiedProperties();
			}
		}
		#endif
	}
}