I am using this code to show the custom menu subpages if you are on the parent page. But what this code also shows is a parent page on a page that has no sub menu, which I would like hidden. Basically only use this code if we are on a page that has a sub page,
class Selective_Walker extends Walker_Nav_Menu
{
function walk( $elements, $max_depth) {
$args = array_slice(func_get_args(), 2);
$output = '';
if ($max_depth < -1) //invalid parameter
return $output;
if (empty($elements)) //nothing to walk
return $output;
$id_field = $this->db_fields['id'];
$parent_field = $this->db_fields['parent'];
// flat display
if ( -1 == $max_depth ) {
$empty_array = array();
foreach ( $elements as $e )
$this->display_element( $e, $empty_array, 1, 0, $args, $output );
return $output;
}
/*
* need to display in hierarchical order
* separate elements into two buckets: top level and children elements
* children_elements is two dimensional array, eg.
* children_elements[10][] contains all sub-elements whose parent is 10.
*/
$top_level_elements = array();
$children_elements = array();
foreach ( $elements as $e) {
if ( 0 == $e->$parent_field )
$top_level_elements[] = $e;
else
$children_elements[ $e->$parent_field ][] = $e;
}
/*
* when none of the elements is top level
* assume the first one must be root of the sub elements
*/
if ( empty($top_level_elements) ) {
$first = array_slice( $elements, 0, 1 );
$root = $first[0];
$top_level_elements = array();
$children_elements = array();
foreach ( $elements as $e) {
if ( $root->$parent_field == $e->$parent_field )
$top_level_elements[] = $e;
else
$children_elements[ $e->$parent_field ][] = $e;
}
}
$current_element_markers = array( 'current-menu-item', 'current-menu-parent', 'current-menu-ancestor' ); //added by continent7
foreach ( $top_level_elements as $e ){ //changed by continent7
// descend only on current tree
$descend_test = array_intersect( $current_element_markers, $e->classes );
if ( !empty( $descend_test ) )
$this->display_element( $e, $children_elements, 2, 0, $args, $output );
}
/*
* if we are displaying all levels, and remaining children_elements is not empty,
* then we got orphans, which should be displayed regardless
*/
/* removed by continent7
if ( ( $max_depth == 0 ) && count( $children_elements ) > 0 ) {
$empty_array = array();
foreach ( $children_elements as $orphans )
foreach( $orphans as $op )
$this->display_element( $op, $empty_array, 1, 0, $args, $output );
}
*/
return $output;
}
}
in the template using:
wp_nav_menu(
array(
'theme_location'=>'primary',
'walker'=>new Selective_Walker()
)
);
I’ve made a free plugin which solves this problem!
https://wordpress.org/plugins/wp-nav-menu-extended/
This plugin extends the native wp_nav_menu function and adds additional options:
Sample Usage:
I have had this exact same issue many times in the past with WordPress. In other CMS’s I’ve used the menus always had an option for the start_depth which made it really easy to implement a secondary or tertiary menu (split menu).
WordPress doesn’t include this function; and many of the solutions online use wp_list_pages which completely ignores the menu manager hierarchy.
After trying different walkers and widgets I finally decided to just write my own plugin that has the start_depth option in it.
you use it like this:
for anyone who is interested you can get it free on the WordPress plugin repository: https://wordpress.org/plugins/wp-nav-plus/