Unity Editor Can't Edit Multiple Objects - unity3d

Question

I want to build a custom inspector for one of my classes... and well... I thought I would start simple ... and I still can't get it to draw the basic inspector:
My editor script is:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
[CustomEditor(typeof(AbilityBluePrint))]
[CanEditMultipleObjects]
public class AbilityBluePrintEditor : Editor
{
public override void OnInspectorGUI()
{
base.OnInspectorGUI();
// Show default inspector property editor
DrawDefaultInspector();
}
}
And the class I want to edit is:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
[CreateAssetMenu(fileName = "New Ability BluePrint", menuName = "Ability BluePrint")]
public class AbilityBluePrint : ScriptableObject {
public AbilityName abilityName;
public Characteristic[] characteritics;
public Effect[] effects;
public float coolDown;
public Sprite icon;
public string description;
}
Any suggestions, on how to solve the "multi-object editing not supported" message I get instead of my beautiful custom editor ??

Answer 1

You need to use Serialized properties if like to use Multiple object edition.
[CustomEditor(typeof(AbilityBluePrint))]
[CanEditMultipleObjects]
public class AbilityBluePrintEditor : Editor
{
var AbilityName : SerializedProperty;
function OnEnable ()
{
// Setup the SerializedProperties
AbilityName = serializedObject.FindProperty ("Ability");
}
function OnInspectorGUI()
{
// Update the serializedProperty - always do this in the beginning of OnInspectorGUI.
serializedObject.Update ();
...

Answer 2

This is not explained in the documentation and I think it is quite important.
Apart from the option of using Serialized Properties, if you are not able to use those, in case you have your own items, not using the automatically managed Serialized Properties, then you have to use "targets" variable instead of "target".
I noted that if you select different types of objects with no shared script, it doesn't show shared properties, so we don't need to check if the targets are all the same type, it is always one or more. Then you do whatever you want to do by hand with each of them, inside a foreach loop.
Here's a working example of the contents of OnInspectorGUI method inside an Editor class with a simple checkbox that is changed across several scripts. Hope it helps.
var myScript = (UnityTerrainWrapper)target;
var allSelectedScripts = targets;
EditorGUI.BeginChangeCheck();
var value = GUILayout.Toggle(myScript.ShowNativeTerrain, "Draw Unity Terrain");
if (EditorGUI.EndChangeCheck())
{
foreach (var script in allSelectedScripts)
((UnityTerrainWrapper)script).ShowNativeTerrain = value;
SceneView.RepaintAll();
}
DrawDefaultInspector();