When is menu_order set for attachments?

I’m having a problem where even in 3.5.1 rearranging the order isn;t setting the menu order values. For me they are all staying ‘0’. Anyone else seeing this?

Ok, I did something myself, based on a snippet I found in this forum. What I’m doing is:

– get the gallery shortcode
– extract the ids
– save the ids as menu_order for the current images.

NOTICE: This probably won’t be adequate for you if you want to use the same image in different galleries.

This one seems to work for me, put it in your functions.php.

function pmc_gallery_menu_order_fix($id) {
        $regex_pattern = get_shortcode_regex();
        preg_match('/\[gallery[^\]]*\](.*)/', stripslashes($_POST['content']), $regex_matches);
        if (substr($regex_matches[0],1,7) == 'gallery') :
            preg_match('/"([^"]+)"/', $regex_matches[0], $attributes);
            $attributes = $attributes[1];
        endif;

        $ids = explode(',', $attributes);
        $images = get_posts( array(
		'post_parent' => $post->ID,
		'numberposts' => '-1',
		'post_status' => 'inherit',
		'post_type' => 'attachment',
		'post_mime_type' => 'image',
		'orderby' => 'menu_order ID',
		'order' => 'ASC'
	) );
	if ( empty($images) ) {
		// no attachments here
	} else {
		foreach ( $images as $attachment_id => $attachment ) {
			if (in_array($attachment->ID, $ids)) {
				$update_post = array();
				$update_post['ID'] = $attachment->ID;
				$update_post['menu_order'] = array_search($attachment->ID, $ids);
				wp_update_post( $update_post );
			};
		}
	}
}
add_action('pre_post_update', 'pmc_gallery_menu_order_fix');

The gallery shortcode in WP 3.5 passes the ids as an attribute now I guess, so rather than rely on the menu_order I just changed my code, like @choeft, to use the passed in order. In my case I actually overriding the gallery shortcode in my theme, so that I can use a custom AJAX gallery for display.

You can see an example here.

My overridden function looks like this:

/*********************
CUSTOM GALLERY
*********************/
//remove default shortcode
remove_shortcode('gallery');
//Add custom gallery shortcode
add_shortcode('gallery', 'php_gallery_shortcode');

function php_gallery_shortcode($atts) {

    global $post;

    if ( ! empty( $atts['ids'] ) ) {
      // 'ids' is explicitly ordered, unless you specify otherwise.
      if ( empty( $atts['orderby'] ) )
        $atts['orderby'] = 'post__in';

      $atts['include'] = $atts['ids'];
    }

    extract(shortcode_atts(array(
      'order'      => 'ASC',
      'orderby'    => 'menu_order ID',
      'id'         => $post->ID,
      'itemtag'    => 'dl',
      'icontag'    => 'dt',
      'captiontag' => 'dd',
      'columns'    => 3,
      'size'       => 'medium',
      'include'    => '',
      'exclude'    => '',
      'link'       => 'file'
    ), $atts));

    $id = intval($id);
    if ( 'RAND' == $order )
      $orderby = 'none';

    if ( !empty($include) ) {
      $_attachments = get_posts( array('include' => $include, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );

      $attachments = array();
      foreach ( $_attachments as $key => $val ) {
        $attachments[$val->ID] = $_attachments[$key];
      }
    } elseif ( !empty($exclude) ) {
      $attachments = get_children( array('post_parent' => $id, 'exclude' => $exclude, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );
    } else {
      $attachments = get_children( array('post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );
    }

    if ( empty($attachments) )
      return '';

    if ( is_feed() ) {
      $output = "\n";
      foreach ( $attachments as $att_id => $attachment )
        $output .= wp_get_attachment_link($att_id, $size, true) . "\n";
      return $output;
    }

    //load styles
    wp_enqueue_style( 'gallery', get_template_directory_uri() . '/library/css/gallery.css');

    //load javascript
    wp_enqueue_script('pmp_gallery_tmpl',get_template_directory_uri() . '/library/js/jquery.tmpl.min.js',array('jquery'),false,true);
    wp_enqueue_script('easing',get_template_directory_uri() . '/library/js/jquery.easing.1.3.js',array('jquery'),false,true);
    wp_enqueue_script('elastislide',get_template_directory_uri() . '/library/js/jquery.elastislide.js',array('jquery'),false,true);
    wp_enqueue_script('pmp_gallery',get_template_directory_uri() . '/library/js/gallery.js',array('jquery'),false,true);

    //Print out thumbnail carousel wrapper opener
    printf('
    <div id="rg-gallery" class="rg-gallery">
    <div class="rg-thumbs">
        <!-- Elastislide Carousel Thumbnail Viewer -->
        <div class="es-carousel-wrapper">
            <div class="es-nav">
                <span class="es-nav-prev">Previous</span>
                <span class="es-nav-next">Next</span>
            </div>
            <div class="es-carousel">
                <ul>
    ');

    //write out thumbnails
    foreach ( $attachments as $image ) {
      $caption = $image->post_excerpt;

      $description = $image->post_content;
      if($description == '') $description = $title;
        $image_alt = get_post_meta($image->ID,'_wp_attachment_image_alt', true);

      $img = wp_get_attachment_image_src($image->ID, 'square-100');
      $img_full = wp_get_attachment_image_src($image->ID, 'pmp-gallery-image');

      // render your gallery here
      printf(
        '<li><a href="#"><img src="%s" data-large="%s" alt="%s" data-description="%s" /></a></li>',$img[0], $img_full[0],$image_alt,$image_alt);
    }

    //write out closing carousel tags
    printf('
                  </ul>
                </div>
            </div>
            <!-- End Elastislide Carousel Thumbnail Viewer -->
        </div><!-- rg-thumbs -->
    </div><!-- rg-gallery -->
    ');

    //write out main javascript to render images
    printf('
    <script id="img-wrapper-tmpl" type="text/x-jquery-tmpl">
      <div class="rg-image-wrapper">
        {{if itemsCount > 1}}
          <div class="rg-image-nav">
            <a href="#" class="rg-image-nav-prev">Previous Image</a>
            <a href="#" class="rg-image-nav-next">Next Image</a>
          </div>
        {{/if}}
        <div class="rg-image"></div>
        <div class="rg-loading"></div>
        <div class="rg-caption-wrapper">
          <div class="rg-caption" style="display:none;">
            <p></p>
          </div>
        </div>
      </div>
    </script>
    ');
}