Unity Inspector History

UnityInspectorHistory.cs

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

/// <summary>
/// To use this create the window and place it above your inspector window for best use
/// </summary>
public class UnityInspectorHistory : EditorWindow
{
    private int currentPoint;

    private List<int> selectionIDs = new List<int>();

    private bool internalOperation;

    [MenuItem("Tools/UnityInspectorHistory/History Window")]
    static void Init()
    {
        UnityInspectorHistory window = (UnityInspectorHistory) EditorWindow.GetWindow(typeof(UnityInspectorHistory));
        window.Show();
        if (Selection.instanceIDs.Length != 0)
            Selection.instanceIDs = new int[] {Selection.instanceIDs[0]};
    }

    void OnGUI()
    {
        GUILayout.Label("History", EditorStyles.boldLabel);
        EditorGUI.BeginChangeCheck();
        string[] history = new String[selectionIDs.Count];

        for (var i = 0; i < selectionIDs.Count; i++)
        {
            string name = "";
            if (EditorUtility.InstanceIDToObject(selectionIDs[i]) != null)
            {
                name = $"{i}: {EditorUtility.InstanceIDToObject(selectionIDs[i]).name}";
            }
            else
            {
                name = $"{i}: unknown";
            }

            history[i] = name;
        }

        if (selectionIDs.Count == 0) return;

        currentPoint = EditorGUILayout.Popup(currentPoint, history);


        if (EditorGUI.EndChangeCheck())
        {
            internalOperation = true;
            if (selectionIDs.Count != 0)
                Selection.instanceIDs = new int[] {selectionIDs[currentPoint]};
            Repaint();
        }

        if (GUILayout.Button("clear"))
        {
            if (selectionIDs.Count != 0)
                selectionIDs = new List<int> {selectionIDs[currentPoint]};
            currentPoint = 0;
            Repaint();
        }


        GUILayout.BeginHorizontal();
        GUILayout.FlexibleSpace();

        if (GUILayout.Button("<", GUILayout.Width(EditorGUIUtility.currentViewWidth / 2)))
        {
            Back();
        }

        GUILayout.FlexibleSpace();

        if (GUILayout.Button(">", GUILayout.Width(EditorGUIUtility.currentViewWidth / 2)))
        {
            Forward();
        }

        GUILayout.FlexibleSpace();
        GUILayout.EndHorizontal();
    }


    void OnSelectionChange()
    {
        if (Selection.instanceIDs == null || Selection.instanceIDs.Length == 0) return;

        int sel = Selection.instanceIDs[0];

        if (selectionIDs.Count == 0)
        {
            selectionIDs.Add(sel);
            currentPoint = 0;
        }
        else if (sel != selectionIDs[selectionIDs.Count - 1] && !internalOperation)
        {
            if (currentPoint < selectionIDs.Count - 1)
            {
                var lastSelected = selectionIDs[currentPoint];
                selectionIDs.RemoveRange(currentPoint, selectionIDs.Count - currentPoint);
                selectionIDs.Add(lastSelected);
                currentPoint = selectionIDs.Count - 1;
            }

            selectionIDs.Add(sel);
            currentPoint = selectionIDs.Count - 1;
        }


        Repaint();
        internalOperation = false;
    }


    public void Back()
    {
        internalOperation = true;
        if (currentPoint > 0)
            currentPoint -= 1;
        if (selectionIDs.Count != 0)
            Selection.instanceIDs = new int[] {selectionIDs[currentPoint]};
        Repaint();
    }

    private void Forward()
    {
        internalOperation = true;
        if (currentPoint < (selectionIDs.Count - 1))
        {
            currentPoint += 1;
        }

        if (selectionIDs.Count != 0)
            Selection.instanceIDs = new int[] {selectionIDs[currentPoint]};
        Repaint();
    }

#region Hotkeys

    [MenuItem("Tools/UnityInspectorHistory/Back _&LEFT", false, 0)] // ALT + LEFT,
    private static void BackHK()
    {
        UnityInspectorHistory window = (UnityInspectorHistory) EditorWindow.GetWindow(typeof(UnityInspectorHistory));
        window.Back();
    }

    [MenuItem("Tools/UnityInspectorHistory/Forward _&RIGHT", false, 1)] // ALT + RIGHT.
    private static void ForwardHK()
    {
        UnityInspectorHistory window = (UnityInspectorHistory) EditorWindow.GetWindow(typeof(UnityInspectorHistory));
        window.Forward();
    }

#endregion
}