Example.cs

using UnityEditor;
using UnityEngine;

[InitializeOnLoad]
public sealed class Example : EditorWindow
{
    private BuildPlayerOptions m_buildPlayerOptions;

    static Example()
    {
        BuildPlayerWindow.RegisterBuildPlayerHandler( OnBuildPlayer );
    }

    private static void OnBuildPlayer( BuildPlayerOptions buildPlayerOptions )
    {
        var example = GetWindow<Example>();
        example.m_buildPlayerOptions = buildPlayerOptions;
    }

    private void OnGUI()
    {
        EditorGUILayout.LabelField( "ここに独自のビルド設定用の GUI を表示する" );
        
        var buildOptions = m_buildPlayerOptions.options;

        var label = ( buildOptions & BuildOptions.AutoRunPlayer ) == 0
                ? "Build"
                : "Build And Run"
            ;

        if ( GUILayout.Button( label ) )
        {
            BuildPlayerWindow.DefaultBuildMethods.BuildPlayer( m_buildPlayerOptions );
        }
    }
}