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Code Reference Classes BP_Walker_Nav_Menu BP_Walker_Nav_Menu::walk()

BP_Walker_Nav_Menu::walk( array $elements, int $max_depth )

Display array of elements hierarchically.

Description

This method is almost identical to the version in Walker::walk(). The only change is on one line which has been commented. An IF was comparing 0 to a non-empty string which was preventing child elements being grouped under their parent menu element.

This caused a problem for BuddyPress because our primary/secondary navigations don’t have a unique numerical ID that describes a hierarchy (we use a slug). Obviously, WordPress Menus use Posts, and those have ID/post_parent.

See also

Parameters

$elements

(Required) See Walker::walk().

$max_depth

(Required) See Walker::walk().

Return

(string) See Walker::walk().

Source

File: bp-core/classes/class-bp-walker-nav-menu.php

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public 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;
 
    $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 ) {
        // BuddyPress: changed '==' to '==='. This is the only change from version in Walker::walk().
        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;
        }
    }
 
    foreach ( $top_level_elements as $e )
        $this->display_element( $e, $children_elements, $max_depth, 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.
     */
    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;
}

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Changelog

Changelog
Version Description
BuddyPress 1.7.0 Introduced.

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