How to translate Widget Description in constructor?

Question

I'm building a localized widget and the translation works everywhere but in the language string in the constructor. I have read that

the whole plugin initialisation has to be bound to the init hook

to avoid that problem, but i don't know to do this because if i try to register the widget with init instead of widgets_init, there is nothing initialised at all.

How to fix that?

My Code:

  class Pinboard_Linkroll_Widget extends WP_Widget {

    // Constants & Properties go here...
    protected $widget_slug = 'pinboard-linkroll-widget';

    /*--------------------------------------------------*/
    /* Constructor
    /*--------------------------------------------------*/

    /**
    * Includes pinboard API class, 
    * Specifies the classname and description, instantiates the widget,
    * loads localization files, and includes necessary stylesheets and JavaScript.
    */
    public function __construct() {

      // include pinboard api class
      // https://github.com/kijin/pinboard-api
      include_once( dirname(__FILE__). '/lib/pinboard-api.php' );


      // load plugin text domain
      add_action( 'init', array( &$this, 'widget_textdomain' ) );

      // actual widget constructor
      parent::__construct(
        $this->get_widget_slug(),
        __( 'Pinboard Linkroll Widget', $this->get_widget_slug() ),
        array(
          'classname'  => $this->get_widget_slug().'-class',
          'description' => __( 'Returns a list of recent Pinboard Links.', $this->get_widget_slug() )
        )
      );

      // handle token errors in admin area (check for valid token and display errors)
      add_action( 'sidebar_admin_setup', array( &$this, 'handle_token_errors' ) );

      // delete transients when last widget instance is deleted
      // http://wordpress.stackexchange.com/questions/95091/how-to-delete-cached-transients-from-a-widget-instance-properly
      add_action( 'sidebar_admin_setup', array( &$this, 'delete_transient' ) );

    } // end constructor


    /**
     * Returns widget slug
     *
     * @since   0.7.0
     * @return  Plugin slug variable.
     */
    public function get_widget_slug() {
      return $this->widget_slug;
    }


    /**
     * Loads the Widget's text domain for localization and translation.
     *
     * @since   0.7.0
     */
    public function widget_textdomain() {
      load_plugin_textdomain( $this->get_widget_slug(), false, $this->get_widget_slug() . '/lang' );
    } // end widget_textdomain

    // WP Widget API functions & other stuff goes here...

  }

  // register widget
  add_action( 'widgets_init', create_function('', 'return register_widget("Pinboard_Linkroll_Widget");') );

}

Answer 1

You have slight timing issues because you generate title first (in constructor call), but postpone text domain load to later (init at default priority). Text domain mus be loaded for __() to translate correctly. Those are not “lazy”, they generate and return strings right where they are called.

Text domain should be loaded very early, Codex recommends at plugins_loaded for plugins.

Probably your class shouldn't be trying to be both valid widget and plugin loader, separate it out.