Wordpress菜单功能

Question

好的，我做了我自己的主题，我用这个代码作为我的菜单：

function the_nav_menu() {
    $menu_name = 'nav-primary';
    if (($locations = get_nav_menu_locations()) && isset($locations[$menu_name])) {
        $menu = wp_get_nav_menu_object($locations[$menu_name]);
        $menu_items = wp_get_nav_menu_items($menu->term_id);
        $current_item = 0;

        foreach ((array) $menu_items as $key => $menu_item) {
            $current_item++;
            $title = $menu_item->title;
            $url = $menu_item->url;
            if($current_item == 3)
                $menu_list .= "\t\t\t\t\t". '<li><a href="#!" class="dropdown-button" data-activates="dropdown-nav">'. $title .'<i class="material-icons right">arrow_drop_down</i></a><ul class="dropdown-content" id="dropdown-nav">' ."\n";
            else
                $menu_list .= "\t\t\t\t\t". '<li><a href="'. $url .'">'. $title .'</a></li>' ."\n";
        }

    } else {
        // $menu_list = '<!-- no list defined -->';
    }
    echo $menu_list . '</ul></li>';
}

当我试图在header.php中使用该菜单时，会出现以下错误：

注意:未定义变量:第56行中的/home/u191493746/public_html/wp-content/themes/startedu/functions.php中的menu_list

有音信吗？

Answer 1

如果将$menu_list="";初始化之前

function the_nav_menu() {
    $menu_name = 'nav-primary';
    $menu_list="";
    if (($locations = get_nav_menu_locations()) && isset($locations[$menu_name])) {
        $menu = wp_get_nav_menu_object($locations[$menu_name]);
        $menu_items = wp_get_nav_menu_items($menu->term_id);
        $current_item = 0;

        foreach ((array) $menu_items as $key => $menu_item) {
            $current_item++;
            $title = $menu_item->title;
            $url = $menu_item->url;
            if($current_item == 3)
                $menu_list .= "\t\t\t\t\t". '<li><a href="#!" class="dropdown-button" data-activates="dropdown-nav">'. $title .'<i class="material-icons right">arrow_drop_down</i></a><ul class="dropdown-content" id="dropdown-nav">' ."\n";
            else
                $menu_list .= "\t\t\t\t\t". '<li><a href="'. $url .'">'. $title .'</a></li>' ."\n";
        }

    } else {
        // $menu_list = '<!-- no list defined -->';
    }
    echo $menu_list . '</ul></li>';
}