/**
  * Initialize the admin by registering the required actions.
  *
  * @since 4.0.0
  */
 private function __construct()
 {
     $this->plugin = BQW_SliderPro::get_instance();
     $this->plugin_slug = $this->plugin->get_plugin_slug();
     // load the admin CSS and JavaScript
     add_action('admin_enqueue_scripts', array($this, 'enqueue_admin_styles'));
     add_action('admin_enqueue_scripts', array($this, 'enqueue_admin_scripts'));
     add_action('admin_menu', array($this, 'add_admin_menu'));
     add_action('wp_ajax_sliderpro_get_slider_data', array($this, 'ajax_get_slider_data'));
     add_action('wp_ajax_sliderpro_save_slider', array($this, 'ajax_save_slider'));
     add_action('wp_ajax_sliderpro_preview_slider', array($this, 'ajax_preview_slider'));
     add_action('wp_ajax_sliderpro_update_presets', array($this, 'ajax_update_presets'));
     add_action('wp_ajax_sliderpro_get_preset_settings', array($this, 'ajax_get_preset_settings'));
     add_action('wp_ajax_sliderpro_get_breakpoints_preset', array($this, 'ajax_get_breakpoints_preset'));
     add_action('wp_ajax_sliderpro_delete_slider', array($this, 'ajax_delete_slider'));
     add_action('wp_ajax_sliderpro_duplicate_slider', array($this, 'ajax_duplicate_slider'));
     add_action('wp_ajax_sliderpro_export_slider', array($this, 'ajax_export_slider'));
     add_action('wp_ajax_sliderpro_import_slider', array($this, 'ajax_import_slider'));
     add_action('wp_ajax_sliderpro_add_slides', array($this, 'ajax_add_slides'));
     add_action('wp_ajax_sliderpro_load_main_image_editor', array($this, 'ajax_load_main_image_editor'));
     add_action('wp_ajax_sliderpro_load_thumbnail_editor', array($this, 'ajax_load_thumbnail_editor'));
     add_action('wp_ajax_sliderpro_load_caption_editor', array($this, 'ajax_load_caption_editor'));
     add_action('wp_ajax_sliderpro_load_html_editor', array($this, 'ajax_load_html_editor'));
     add_action('wp_ajax_sliderpro_load_layers_editor', array($this, 'ajax_load_layers_editor'));
     add_action('wp_ajax_sliderpro_add_layer_settings', array($this, 'ajax_add_layer_settings'));
     add_action('wp_ajax_sliderpro_load_settings_editor', array($this, 'ajax_load_settings_editor'));
     add_action('wp_ajax_sliderpro_load_content_type_settings', array($this, 'ajax_load_content_type_settings'));
     add_action('wp_ajax_sliderpro_add_breakpoint', array($this, 'ajax_add_breakpoint'));
     add_action('wp_ajax_sliderpro_add_breakpoint_setting', array($this, 'ajax_add_breakpoint_setting'));
     add_action('wp_ajax_sliderpro_get_taxonomies', array($this, 'ajax_get_taxonomies'));
     add_action('wp_ajax_sliderpro_clear_all_cache', array($this, 'ajax_clear_all_cache'));
     add_action('wp_ajax_sliderpro_close_getting_started', array($this, 'ajax_close_getting_started'));
 }
 /**
  * Return the current class instance.
  *
  * @since 4.0.0
  * 
  * @return object The instance of the current class.
  */
 public static function get_instance()
 {
     if (self::$instance == null) {
         self::$instance = new self();
     }
     return self::$instance;
 }