我正在尝试使用 PHP 创建从 MySQL 数据库中获取数据的动态多级菜单。我已经设法使用这种格式在 php 数组中订购菜单项:
-----------------------
Array
(
[1] => Array
    (
        [id] => 1
        [ubicacion] => top_a
        [nivel] => 1
        [parent_id] => 
        [tipo] => link
        [link] => http://www.google.com
        [titulo] => Google
        [alias] => google_es
        [children] => Array
            (
                [3] => Array
                    (
                        [id] => 3
                        [ubicacion] => top_a
                        [nivel] => 2
                        [parent_id] => 1
                        [tipo] => link
                        [link] => http://www.gmail.com
                        [titulo] => Gmail
                        [alias] => gmail
                        [children] => Array
                            (
                                [4] => Array
                                    (
                                        [id] => 4
                                        [ubicacion] => top_a
                                        [nivel] => 3
                                        [parent_id] => 3
                                        [tipo] => link
                                        [link] => www.inbox.gmail.com
                                        [titulo] => Inbox
                                        [alias] => inbox_gmail
                                    )
                            )
                    )
            )
    )
[2] => Array
    (
        [id] => 2
        [ubicacion] => top_a
        [nivel] => 1
        [parent_id] => 
        [tipo] => link
        [link] => http://www.yahoo.com
        [titulo] => Yahoo
        [alias] => yahoo
    )
)
-----------------------
问题是我无法弄清楚如何以适用于 n 级的方式将此数组输出为 HTML 标记。我可以使用固定数量的级别来做到这一点,如下所示:
foreach($menu_array as $menu) {
 echo "<li><a href='{$menu['link']}'>{$menu['titulo']}</a>";
 if (array_key_exists('children',$menu)) {
    echo "<ul>";
    foreach ($menu['children'] as $child_menu) {
        echo "<li><a href='{$child_menu['link']}'>{$child_menu['titulo']}</a>";
        if (array_key_exists('children',$child_menu)) {
            echo "<ul>";
            foreach ($child_menu['children'] as $child2_menu) {
                echo "<li><a href='{$child2_menu['link']}'>{$child2_menu['titulo']}</a>";
            }
            echo "</ul>";
        }
    }
    echo "</ul>";
}
echo "</li>";
}
但这仅适用于 3 个级别,我知道应该有办法解决这个问题,我知道我不是第一个面临多维数组的 HTML 输出问题的人。