"current" class on top level menu item with wp_nav_menu - php

Question

I've created a wordpress menu with wp_nav_menu.
my structure looks like:
Page
Category
Page
Page
Page
If I open a post in "Category", there is no "current" class on the top level of the menu – only on "Category". Nesting only with pages works fine on multi level menus.
Is there a way to fix that?

Answer 1

1) Either write a custom walker http://codex.wordpress.org/Function_Reference/wp_nav_menu#Using_a_Custom_Walker_Function to add a current class when that category is called;
2) Or, (not the most elegant): find your page ID for the menu item you want - 1000 in the example below - to highlight as current, select that category - is_category - and then add the current class - addClass - with jQuery:
<?php if (is_category('my-category')) { ?>
<script type="text/javascript">
jQuery(function($) {
$(document).ready(function() {
$('#menu-main-menu li.menu-item-1000').addClass('current-menu-item');
}); });
</script>
<?php } ?>

Answer 2

ahh... found the solution in the wordpress codex. this works fine for me:
add_filter( 'wp_nav_menu_objects', 'add_menu_parent_class' );
function add_menu_parent_class( $items ) {
$parents = array();
foreach ( $items as $item ) {
if ( $item->menu_item_parent && $item->menu_item_parent > 0 ) {
$parents[] = $item->menu_item_parent;
}
}
foreach ( $items as $item ) {
if ( in_array( $item->ID, $parents ) ) {
$item->classes[] = 'menu-parent-item';
}
}
return $items;
}