概要

using UnityEditor;

[InitializeOnLoad]
public static class Example
{
    static Example()
    {
        EditorApplication.playModeStateChanged += OnChange;
    }

    private static void OnChange( PlayModeStateChange state )
    {
        if ( state == PlayModeStateChange.ExitingEditMode )
        {
            EditorApplication.isPlaying = false;
        }
    }
}