Default Custom Inspector-Editor for Unity3D with ReorderableLists for arrays handling

CustomEditorBase.cs

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

[CustomEditor(typeof(UnityEngine.Object), true, isFallback = true)]
[CanEditMultipleObjects]
public class CustomEditorBase : Editor
{
	private Dictionary<string, ReorderableListProperty> reorderableLists;

	protected virtual void OnEnable()
	{
		this.reorderableLists = new Dictionary<string, ReorderableListProperty>(10);
	}

	~CustomEditorBase()
	{
		this.reorderableLists.Clear();
		this.reorderableLists = null;
	}

	public override void OnInspectorGUI()
	{
		EditorGUILayout.LabelField("Custom Editor", EditorStyles.centeredGreyMiniLabel);
		Color cachedGuiColor = GUI.color;
		serializedObject.Update();
		var property = serializedObject.GetIterator();
		var next = property.NextVisible(true);
		if (next)
			do
			{
				GUI.color = cachedGuiColor;
				this.HandleProperty(property);
			} while (property.NextVisible(false));
		serializedObject.ApplyModifiedProperties();
	}

	protected void HandleProperty(SerializedProperty property)
	{
		//Debug.LogFormat("name: {0}, displayName: {1}, type: {2}, propertyType: {3}, path: {4}", property.name, property.displayName, property.type, property.propertyType, property.propertyPath);
		bool isdefaultScriptProperty = property.name.Equals("m_Script") && property.type.Equals("PPtr<MonoScript>") && property.propertyType == SerializedPropertyType.ObjectReference && property.propertyPath.Equals("m_Script");
		bool cachedGUIEnabled = GUI.enabled;
		if (isdefaultScriptProperty)
			GUI.enabled = false;
		//var attr = this.GetPropertyAttributes(property);
		if (property.isArray && property.propertyType != SerializedPropertyType.String)
			this.HandleArray(property);
		else
			EditorGUILayout.PropertyField(property, property.isExpanded);
		if (isdefaultScriptProperty)
			GUI.enabled = cachedGUIEnabled;
	}

	protected void HandleArray(SerializedProperty property)
	{
		var listData = this.GetReorderableList(property);
		listData.IsExpanded.target = property.isExpanded;
		if ((!listData.IsExpanded.value && !listData.IsExpanded.isAnimating) || (!listData.IsExpanded.value && listData.IsExpanded.isAnimating))
		{
			EditorGUILayout.BeginHorizontal();
			property.isExpanded = EditorGUILayout.ToggleLeft(string.Format("{0}[]", property.displayName), property.isExpanded, EditorStyles.boldLabel);
			EditorGUILayout.LabelField(string.Format("size: {0}", property.arraySize));
			EditorGUILayout.EndHorizontal();
		}
		else {
			if (EditorGUILayout.BeginFadeGroup(listData.IsExpanded.faded))
				listData.List.DoLayoutList();
			EditorGUILayout.EndFadeGroup();
		}
	}

	protected object[] GetPropertyAttributes(SerializedProperty property)
	{
		return this.GetPropertyAttributes<PropertyAttribute>(property);
	}

	protected object[] GetPropertyAttributes<T>(SerializedProperty property) where T : System.Attribute
	{
		System.Reflection.BindingFlags bindingFlags = System.Reflection.BindingFlags.GetField
			| System.Reflection.BindingFlags.GetProperty
			| System.Reflection.BindingFlags.IgnoreCase
			| System.Reflection.BindingFlags.Instance
			| System.Reflection.BindingFlags.NonPublic
			| System.Reflection.BindingFlags.Public;
		if (property.serializedObject.targetObject == null)
			return null;
		var targetType = property.serializedObject.targetObject.GetType();
		var field = targetType.GetField(property.name, bindingFlags);
		if (field != null)
			return field.GetCustomAttributes(typeof(T), true);
		return null;
	}

	private ReorderableListProperty GetReorderableList(SerializedProperty property)
	{
		ReorderableListProperty ret = null;
		if (this.reorderableLists.TryGetValue(property.name, out ret))
		{
			ret.Property = property;
			return ret;
		}
		ret = new ReorderableListProperty(property);
		this.reorderableLists.Add(property.name, ret);
		return ret;
	}

	#region Inner-class ReorderableListProperty
	private class ReorderableListProperty
	{
		public AnimBool IsExpanded { get; private set; }

		/// <summary>
		/// ref http://va.lent.in/unity-make-your-lists-functional-with-reorderablelist/
		/// </summary>
		public ReorderableList List { get; private set; }

		private SerializedProperty _property;
		public SerializedProperty Property
		{
			get { return this._property; }
			set
			{
				this._property = value;
				this.List.serializedProperty = this._property;
			}
		}

		public ReorderableListProperty(SerializedProperty property)
		{
			this.IsExpanded = new AnimBool(property.isExpanded);
			this.IsExpanded.speed = 1f;
			this._property = property;
			this.CreateList();
		}

		~ReorderableListProperty()
		{
			this._property = null;
			this.List = null;
		}

		private void CreateList()
		{
			bool dragable = true, header = true, add = true, remove = true;
			this.List = new ReorderableList(this.Property.serializedObject, this.Property, dragable, header, add, remove);
			this.List.drawHeaderCallback += rect => this._property.isExpanded = EditorGUI.ToggleLeft(rect, this._property.displayName, this._property.isExpanded, EditorStyles.boldLabel);
			this.List.onCanRemoveCallback += (list) => { return this.List.count > 0; };
			this.List.drawElementCallback += this.drawElement;
			this.List.elementHeightCallback += (idx) => { return Mathf.Max(EditorGUIUtility.singleLineHeight, EditorGUI.GetPropertyHeight(this._property.GetArrayElementAtIndex(idx), GUIContent.none, true)) + 4.0f; };
		}

		private void drawElement(Rect rect, int index, bool active, bool focused)
		{
			if (this._property.GetArrayElementAtIndex(index).propertyType == SerializedPropertyType.Generic)
			{
				EditorGUI.LabelField(rect, this._property.GetArrayElementAtIndex(index).displayName);
			}
			//rect.height = 16;
			rect.height = EditorGUI.GetPropertyHeight(this._property.GetArrayElementAtIndex(index), GUIContent.none, true);
			rect.y += 1;
			EditorGUI.PropertyField(rect, this._property.GetArrayElementAtIndex(index), GUIContent.none, true);
			this.List.elementHeight = rect.height + 4.0f;
		}
	}
	#endregion
}

JavaBehaviourScript.js

#pragma strict

var myInt : int = 5;

var myFloat: float = 10.56;

public var players : GameObject[];
public var floats : float[];
public var numbers : int[];
public var vectors : Vector3[];

function Start () {

}

function Update () {

}

Tester.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
//using System;

[System.Flags]
public enum Stuff{
    Coke        = 1 << 0,
    Hamburguer  = 1 << 1,
    Pizza       = 1 << 2,
    Hotdog      = 1 << 3,
    Pepsi       = 1 << 4,
    Beer        = 1 << 5,
    BuffaloWings = 1 << 6,
    IceCream    = 1 << 7,

}

[System.Serializable]
public struct SomeOtherData
{
    public int aNumber;
    [Range(0f, 1f)]
    public float anotherNumber;
    public Vector3 position;
}

public class Tester : MonoBehaviour {

    public int aNumber;
    public int AFloat;
    [Range(0f, 100f)]
    public float AFloatRangeAttr;
    public string aString;

    public int[] aNumerArray;
    public float[] aFloatArray;
    [Range(0.0f, 100.0f)]
    public float[] anotherFloatArray;

    [SerializeField]
    private List<Stuff> privateListOfStuff;

    [SerializeField]
    private SomeOtherData NestedData;

    [SerializeField]
    private AudioMixerClip mixerClip;

    [SerializeField]
    private AudioMixerClip[] mixerClips;
    
}

How can I remove the foldout in the elements? I find it slows me down having to expand them and it looks kinda bad. I removed the expand button at the top but I can't find anything in the code about the foldouts. The regular reorderable lists don't use these so I assume you're either using something else or have manually added them. Any ideas?

@t0chas, this doesn't work too well with recent version of Unity.

1. "Element 0, Element 1, etc" text is displayed in grey behind the elements themselves: https://i.imgur.com/YecUs7z.png
2. There is a big delay when expanding/collapsing the array.
3. Dragging objects to add new elements is not working.
4. Nested arrays not working.

I think the main flaw is that you shouldn't use Custom Inspector to solve this problem, but PropertyDrawer instead. I know they are harder to work with but it's the only way to do it properly.

I recommend use https://github.com/SubjectNerd-Unity/ReorderableInspector It does solve the issue with folding and provides many more features.