概要

using UnityEditor;
using UnityEngine;

public sealed class Example : EditorWindow
{
    private int selectedIndex1;
    private int selectedIndex2;

    [MenuItem( "Tools/Example" )]
    private static void Init()
    {
        GetWindow<Example>();
    }

    private void OnGUI()
    {
        var texts = new []
        {
            "a",
            "b",
            "c",
            "d",
            "e",
        };

        selectedIndex1 = GUILayout.Toolbar( selectedIndex1, texts );

        var textures = new []
        {
            AssetDatabase.LoadAssetAtPath<Texture2D>( "Assets/Editor/pikachu.png" ),
            AssetDatabase.LoadAssetAtPath<Texture2D>( "Assets/Editor/bullbasaur.png" ),
            AssetDatabase.LoadAssetAtPath<Texture2D>( "Assets/Editor/charmander.png" ),
            AssetDatabase.LoadAssetAtPath<Texture2D>( "Assets/Editor/squirtle.png" ),
        };

        selectedIndex2 = GUILayout.Toolbar( selectedIndex2, textures );
    }
}