/**
  * Initialize the plugin by loading admin scripts & styles and adding a
  * settings page and menu.
  *
  * @since     1.0.0
  */
 private function __construct()
 {
     /*
      * @TODO :
      *
      * - Uncomment following lines if the admin class should only be available for super admins
      */
     /* if( ! is_super_admin() ) {
     			return;
     		} */
     /*
      * Call $plugin_slug from public plugin class.
      */
     $plugin = Background_Music_Player_Lite::get_instance();
     $this->plugin_slug = $plugin->get_plugin_slug();
     // Load admin style sheet and JavaScript.
     add_action('admin_enqueue_scripts', array($this, 'enqueue_admin_styles'));
     add_action('admin_enqueue_scripts', array($this, 'enqueue_admin_scripts'));
     // Add the options page and menu item.
     add_action('admin_menu', array($this, 'add_plugin_admin_menu'));
     add_action('admin_init', array($this, 'admin_options_init'));
     add_action('admin_init', array($this, 'popup_change_button_text_filter'));
     // Add an action link pointing to the options page.
     $plugin_basename = plugin_basename(plugin_dir_path(__DIR__) . $this->plugin_slug . '.php');
     add_filter('plugin_action_links_' . $plugin_basename, array($this, 'add_action_links'));
 }
 /**
  * Return an instance of this class.
  *
  * @since     1.0.0
  *
  * @return    object    A single instance of this class.
  */
 public static function get_instance()
 {
     // If the single instance hasn't been set, set it now.
     if (null == self::$instance) {
         self::$instance = new self();
     }
     return self::$instance;
 }