Php 沃克导航菜单更改（带div）

我正在使用Walker_Nav_菜单功能开发自定义菜单系统。我几乎让它工作，但我不能通过一些障碍，我希望有人可以帮助

我想达到什么目标

<nav id="menu">
    <ul>
        <li><a href="/">Home</a></li>
        <li><a href="/about-us">About Us</a></li>
        <li>
            <span>Second Layer</span>
            <div>
                <ul>
                    <li><a href="/second-layer/second-layer/">Second Layer</a></li>
                    <li><a href="/second-layer/blah-blah/">blah blah</a></li>
                </ul>
            </div>
        </li>
    </ul>
</nav>

---

试试这个代码。您会注意到，我在菜单描述副本周围缠绕了span标记。请随意取消该呼叫，并将您需要的任何内容放入其中

在header.php文件中调用newwalker菜单，如下所示

<?php
      if (has_nav_menu('primary_navigation')) :
        wp_nav_menu(array('theme_location' => 'primary_navigation','items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>', 'menu_class' => 'nav'));
      endif;
    ?>

//放入functions.php

    class Roots_Nav_Walker extends Walker_Nav_Menu {
  function check_current($classes) {
    return preg_match('/(current[-_])|active|dropdown/', $classes);
  }

  function start_lvl(&$output, $depth = 0, $args = array()) {
    $output .= "\n<span>Span here</span><div class='down'><ul class=\"dropdown-menu\">\n";
  }

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

    parent::start_el($item_html, $item, $depth, $args);

    if ($item->is_dropdown && ($depth === 0)) {



      $item_html = str_replace('<a', '<a class="dropdown-toggle" data-toggle="dropdown" data-target="#"', $item_html);
      $item_html = str_replace('</a>', '</a>', $item_html);

    }
    elseif (stristr($item_html, 'li class="divider')) {
      $item_html = preg_replace('/<a[^>]*>.*?<\/a>/iU', '', $item_html);
    }
    elseif (stristr($item_html, 'li class="nav-header')) {
      $item_html = preg_replace('/<a[^>]*>(.*)<\/a>/iU', '$1', $item_html);
    }

    $item_html = apply_filters('roots_wp_nav_menu_item', $item_html);


    $output .= $item_html;

     }

  function display_element($element, &$children_elements, $max_depth, $depth = 0, $args, &$output) {
    $element->is_dropdown = ((!empty($children_elements[$element->ID]) && (($depth + 1) < $max_depth || ($max_depth === 0))));

    if ($element->is_dropdown) {
      if ($depth === 0) {
        $element->classes[] = 'dropdown';
      } elseif ($depth === 1) {
        $element->classes[] = 'dropdown-submenu';
      }
    }

    parent::display_element($element, $children_elements, $max_depth, $depth, $args, $output);
  }
}

/** remove container */
function nav_menu_args($args = '') {
  $nav_menu_args['container'] = false;

  if (!$args['items_wrap']) {
    $nav_menu_args['items_wrap'] = '<ul class="%2$s">%3$s</ul>';
  }

  if (current_theme_supports('bootstrap-top-navbar')) {
    $nav_menu_args['depth'] = 3;
  }

  if (!$args['walker']) {
    $nav_menu_args['walker'] = new Roots_Nav_Walker();
  }

  return array_merge($args, $nav_menu_args);
}
add_filter('wp_nav_menu_args', 'nav_menu_args');

---

很抱歉，它不工作-它根本不输出span，也不输出div。同时收到此错误警告：str_repeat预期参数2很长，中给出了对象

<?php
      if (has_nav_menu('primary_navigation')) :
        wp_nav_menu(array('theme_location' => 'primary_navigation','items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>', 'menu_class' => 'nav'));
      endif;
    ?>

    class Roots_Nav_Walker extends Walker_Nav_Menu {
  function check_current($classes) {
    return preg_match('/(current[-_])|active|dropdown/', $classes);
  }

  function start_lvl(&$output, $depth = 0, $args = array()) {
    $output .= "\n<span>Span here</span><div class='down'><ul class=\"dropdown-menu\">\n";
  }

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

    parent::start_el($item_html, $item, $depth, $args);

    if ($item->is_dropdown && ($depth === 0)) {



      $item_html = str_replace('<a', '<a class="dropdown-toggle" data-toggle="dropdown" data-target="#"', $item_html);
      $item_html = str_replace('</a>', '</a>', $item_html);

    }
    elseif (stristr($item_html, 'li class="divider')) {
      $item_html = preg_replace('/<a[^>]*>.*?<\/a>/iU', '', $item_html);
    }
    elseif (stristr($item_html, 'li class="nav-header')) {
      $item_html = preg_replace('/<a[^>]*>(.*)<\/a>/iU', '$1', $item_html);
    }

    $item_html = apply_filters('roots_wp_nav_menu_item', $item_html);


    $output .= $item_html;

     }

  function display_element($element, &$children_elements, $max_depth, $depth = 0, $args, &$output) {
    $element->is_dropdown = ((!empty($children_elements[$element->ID]) && (($depth + 1) < $max_depth || ($max_depth === 0))));

    if ($element->is_dropdown) {
      if ($depth === 0) {
        $element->classes[] = 'dropdown';
      } elseif ($depth === 1) {
        $element->classes[] = 'dropdown-submenu';
      }
    }

    parent::display_element($element, $children_elements, $max_depth, $depth, $args, $output);
  }
}

/** remove container */
function nav_menu_args($args = '') {
  $nav_menu_args['container'] = false;

  if (!$args['items_wrap']) {
    $nav_menu_args['items_wrap'] = '<ul class="%2$s">%3$s</ul>';
  }

  if (current_theme_supports('bootstrap-top-navbar')) {
    $nav_menu_args['depth'] = 3;
  }

  if (!$args['walker']) {
    $nav_menu_args['walker'] = new Roots_Nav_Walker();
  }

  return array_merge($args, $nav_menu_args);
}
add_filter('wp_nav_menu_args', 'nav_menu_args');