Property drawer / attribute can't being serialized

Hello everyone !

I'm trying to code a property attribute [ InputeName ] that allow to get all Project Settings input axes name into a dropdown list in the inspector to choose the value of componant field like the picture below showing it.



It work perfectly except one major problem... when I enter play mode or change scene, dropdown list are reset to the first element of the list ( horizontal). I think it's because something isn't serialized but I don't know what and why. I'm totally new at editor coding and after research on the net I found people with the same problem as me but the solution provided don't work for me. This is mu code :

Code (CSharp):

1. using UnityEngine;
2.  
3. public class InputNameAttribute : PropertyAttribute
4. {
5.     [SerializeField]
6.     public string inputName;
7.  
8. }
9.  
10. -----------------------------------------------
11. -----------------------------------------------
12.  
13. using UnityEditor;
14. using UnityEngine;
15.  
16. [CustomPropertyDrawer(typeof(InputNameAttribute))]
17. public class InputNameDrawer : PropertyDrawer
18. {
19.     private int index = 0;
20.     public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
21.     {
22.         InputNameAttribute inputNameAttribute = attribute as InputNameAttribute;
23.         if (!property.propertyType.Equals(SerializedPropertyType.String))
24.         {
25.             EditorGUI.LabelField(position, label.text, "Input name attribute only work with string type.");
26.         }
27.         else
28.         {
29.             string[] list = GetInputManagerAxisList();
30.             index  = EditorGUI.Popup(position, property.displayName, index, list);
31.             property.stringValue = list[index];
32.         }
33.  
34.     }
35.  
36.     private string[] GetInputManagerAxisList()
37.     {
38.         SerializedObject inputManager = new SerializedObject(AssetDatabase.LoadAllAssetsAtPath("ProjectSettings/InputManager.asset")[0]);
39.         SerializedProperty axis = inputManager.FindProperty("m_Axes");
40.         string[] inputNameList = new string[axis.arraySize];
41.         int i = 0;
42.         foreach (SerializedProperty axe in axis)
43.         {
44.             inputNameList[i++] = axe.FindPropertyRelative("m_Name").stringValue;
45.         }
46.  
47.         return inputNameList;
48.     }
49. }

 

Code (CSharp):

1. private int index = 0;

You're resetting the index every time you instantiate the property drawer. Instead of that you need to find the index that should be selected and pass that to Popup.

Code (CSharp):

1. int index = Array.IndexOf(list, property.displayName);