Codice per il Widget Post Recenti

Dai un'occhiata a wp-includes\default-widgets.php.

/**
 * Classe del Widget Recent_Posts
 *
 * @since 2.8.0
 */
class WP_Widget_Recent_Posts extends WP_Widget {

    function __construct() {
        $widget_ops = array('classname' => 'widget_recent_entries', 'description' => __( "Gli articoli più recenti del tuo sito") );
        parent::__construct('recent-posts', __('Articoli Recenti'), $widget_ops);
        $this->alt_option_name = 'widget_recent_entries';

        add_action( 'save_post', array($this, 'flush_widget_cache') );
        add_action( 'deleted_post', array($this, 'flush_widget_cache') );
        add_action( 'switch_theme', array($this, 'flush_widget_cache') );
    }

    function widget($args, $instance) {
        $cache = wp_cache_get('widget_recent_posts', 'widget');

        if ( !is_array($cache) )
            $cache = array();

        if ( ! isset( $args['widget_id'] ) )
            $args['widget_id'] = $this->id;

        if ( isset( $cache[ $args['widget_id'] ] ) ) {
            echo $cache[ $args['widget_id'] ];
            return;
        }

        ob_start();
        extract($args);

        $title = ( ! empty( $instance['title'] ) ) ? $instance['title'] : __( 'Articoli Recenti' );
        $title = apply_filters( 'widget_title', $title, $instance, $this->id_base );
        $number = ( ! empty( $instance['number'] ) ) ? absint( $instance['number'] ) : 10;
        if ( ! $number )
            $number = 10;
        $show_date = isset( $instance['show_date'] ) ? $instance['show_date'] : false;

        $r = new WP_Query( apply_filters( 'widget_posts_args', array( 'posts_per_page' => $number, 'no_found_rows' => true, 'post_status' => 'publish', 'ignore_sticky_posts' => true ) ) );
        if ($r->have_posts()) :
?>
        <?php echo $before_widget; ?>
        <?php if ( $title ) echo $before_title . $title . $after_title; ?>
        <ul>
        <?php while ( $r->have_posts() ) : $r->the_post(); ?>
            <li>
                <a href="<?php the_permalink() ?>" title="<?php echo esc_attr( get_the_title() ? get_the_title() : get_the_ID() ); ?>"><?php if ( get_the_title() ) the_title(); else the_ID(); ?></a>
            <?php if ( $show_date ) : ?>
                <span class="post-date"><?php echo get_the_date(); ?></span>
            <?php endif; ?>
            </li>
        <?php endwhile; ?>
        </ul>
        <?php echo $after_widget; ?>
<?php
        // Ripristina il global $the_post in quanto questa query lo avrà modificato
        wp_reset_postdata();

        endif;

        $cache[$args['widget_id']] = ob_get_flush();
        wp_cache_set('widget_recent_posts', $cache, 'widget');
    }

    function update( $new_instance, $old_instance ) {
        $instance = $old_instance;
        $instance['title'] = strip_tags($new_instance['title']);
        $instance['number'] = (int) $new_instance['number'];
        $instance['show_date'] = (bool) $new_instance['show_date'];
        $this->flush_widget_cache();

        $alloptions = wp_cache_get( 'alloptions', 'options' );
        if ( isset($alloptions['widget_recent_entries']) )
            delete_option('widget_recent_entries');

        return $instance;
    }

    function flush_widget_cache() {
        wp_cache_delete('widget_recent_posts', 'widget');
    }

    function form( $instance ) {
        $title     = isset( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';
        $number    = isset( $instance['number'] ) ? absint( $instance['number'] ) : 5;
        $show_date = isset( $instance['show_date'] ) ? (bool) $instance['show_date'] : false;
?>
        <p><label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Titolo:' ); ?></label>
        <input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo $title; ?>" /></p>

        <p><label for="<?php echo $this->get_field_id( 'number' ); ?>"><?php _e( 'Numero di articoli da mostrare:' ); ?></label>
        <input id="<?php echo $this->get_field_id( 'number' ); ?>" name="<?php echo $this->get_field_name( 'number' ); ?>" type="text" value="<?php echo $number; ?>" size="3" /></p>

        <p><input class="checkbox" type="checkbox" <?php checked( $show_date ); ?> id="<?php echo $this->get_field_id( 'show_date' ); ?>" name="<?php echo $this->get_field_name( 'show_date' ); ?>" />
        <label for="<?php echo $this->get_field_id( 'show_date' ); ?>"><?php _e( 'Mostrare la data dell\'articolo?' ); ?></label></p>
<?php
    }
}

Se modifichi questo Widget, assicurati di effettuare un fork e registrare il tuo Widget modificato come un nuovo Widget.

Modifica

Come effettuare un fork di un Widget core

Inizia con la voce del Codex sull'API dei Widget.

1. Rinomina il Widget

   Cambia questo:

   class WP_Widget_Recent_Posts extends WP_Widget {}
   

   ...in questo:

   class wpse97411_Widget_Recent_Posts extends WP_Widget {}
   

2. Modifica la classe del Widget in base alle tue esigenze

3. Registra il tuo Widget:

   function wpse97413_register_custom_widgets() {
       register_widget( 'wpse97411_Widget_Recent_Posts' );
   }
   add_action( 'widgets_init', 'wpse97413_register_custom_widgets' );