Sample Code - Custom Editor Menu and Window Sample

[Unity3d] Custom Editor Menu and Window Sample
(Following file must be in "Editor" folder under the "Assets" folder)

using UnityEditor;
using UnityEngine;

public class MyWindow : EditorWindow
{
    string myString = "Hello World";
    bool groupEnabled;
    bool myBool = true;
    float myFloat = 1.23f;

    GameObject myGameObject;

    // Add menu item named "My Window" to the Window menu
    [MenuItem("CustomWindow/My Window")]
    public static void ShowWindow()
    {
        //Show existing window instance. If one doesn't exist, make one.
        EditorWindow.GetWindow(typeof(MyWindow));
    }

    void OnGUI()
    {
        GUILayout.Label("Base Settings", EditorStyles.boldLabel);
        myString = EditorGUILayout.TextField("Text Field", myString);


        groupEnabled = EditorGUILayout.BeginToggleGroup("Optional Settings", groupEnabled);
        myBool = EditorGUILayout.Toggle("Toggle", myBool);
        myFloat = EditorGUILayout.Slider("Slider", myFloat, -3, 3);
        EditorGUILayout.EndToggleGroup();

        GUILayout.Label("This is Label", new GUILayoutOption[0]);
        myGameObject = (GameObject)EditorGUILayout.ObjectField("Target", myGameObject, typeof(GameObject), true, new GUILayoutOption[0]);

    }
}