field = $field; $this->meta = (array) $meta; } /** * Display array of elements hierarchically. * * @param array $options An array of options. * * @return string */ public function walk( $options ) { $children = []; foreach ( $options as $option ) { $parent = $option->parent ?? 0; $children[ $parent ][] = $option; } $top_level = isset( $children[0] ) ? 0 : $options[0]->parent; return $this->display_level( $children, $top_level, true ); } /** * Display a hierarchy level. * * @param array $options An array of options. * @param int $parent_id Parent item ID. * @param bool $active Whether to show or hide. * * @return string */ public function display_level( $options, $parent_id = 0, $active = false ) { $field = $this->field; $walker = new RWMB_Walker_Select( $field, $this->meta ); $attributes = RWMB_Field::call( 'get_attributes', $field, $this->meta ); $children = $options[ $parent_id ]; $output = sprintf( '

'; foreach ( $children as $child ) { if ( isset( $options[ $child->value ] ) ) { $output .= $this->display_level( $options, $child->value, in_array( $child->value, $this->meta ) && $active ); } } $output .= '

'; return $output; } }