这应该可以帮你。。(UNTESTED)

在主题文件夹中创建一个名为nav menu walker的文件。并将此文件包含在主题函数中。php文件。

nav-menu-walker.php

class My_Nav_Menu_Walker extends Walker_Nav_Menu {

    function start_el( &$output, $item, $depth = 0, $args, $id = 0 ) {

        $indent = ( $depth ) ? str_repeat( "\\t", $depth ) : \'\';

        $class_names = $value = \'\';

        $classes = empty( $item->classes ) ? array() : (array) $item->classes;
        $classes[] = \'menu-item-\' . $item->ID;

        $class_names = join( \' \', apply_filters( \'nav_menu_css_class\', array_filter( $classes ), $item, $args ) );
        $class_names = $class_names ? \' class="\' . esc_attr( $class_names ) . \'"\' : \'\';

        $id = apply_filters( \'nav_menu_item_id\', \'menu-item-\'. $item->ID, $item, $args );
        $id = $id ? \' id="\' . esc_attr( $id ) . \'"\' : \'\';

        $item_output = $args->before;

        $output .= $indent . \'<li\' . $id . $value . $class_names .\'>\';

        $attributes  = ! empty( $item->attr_title ) ? \' title="\'  . esc_attr( $item->attr_title ) .\'"\' : \'\';
        $attributes .= ! empty( $item->target )     ? \' target="\' . esc_attr( $item->target     ) .\'"\' : \'\';
        $attributes .= ! empty( $item->xfn )        ? \' rel="\'    . esc_attr( $item->xfn        ) .\'"\' : \'\';
        $attributes .= ! empty( $item->url )        ? \' href="\'   . esc_attr( $item->url        ) .\'"\' : \'\';

        if ( $args->has_children ) {

            $item_output .= \'<a\'. $attributes .\'>\';
            $item_output .= $args->link_before . apply_filters( \'the_title\', $item->title, $item->ID ) . $args->link_after;
            $item_output .= \'</a>\';

        } else {

            $item_output .= \'<span>\';
            $item_output .= apply_filters( \'the_title\', $item->title, $item->ID );
            $item_output .= \'</span>\';         

        }

        $item_output .= $args->after;

        $output .= apply_filters( \'walker_nav_menu_start_el\', $item_output, $item, $depth, $args );     

    }

    function display_element($element, &$children_elements, $max_depth, $depth=0, $args, &$output) {
        $id_field = $this->db_fields[\'id\'];
        if ( is_object( $args[0] ) ) {
            $args[0]->has_children = ! empty( $children_elements[$element->$id_field] );
        }
        return parent::display_element( $element, $children_elements, $max_depth, $depth, $args, $output );
    }    

}

        <?php 
            wp_nav_menu(
                array(
                    \'theme_location\'    =>  \'primary-menu\',
                    \'walker\'            =>  new My_Nav_Menu_Walker()
                )
            ); 
        ?>

试试看！