数组中的树菜单

Question

I have array:

parent 1 is first step!

Array
(
    [0] => Array
        (
            [categoryID] => 1
            [parent] => 1
            [name] => 111
        )

    [1] => Array
        (
            [categoryID] => 2
            [parent] => 1
            [name] => 2222
        )

    [2] => Array
        (
            [categoryID] => 3
            [parent] => 2
            [name] => 3333
        )
    [3] => Array
        (
            [categoryID] => 4
            [parent] => 3
            [name] => 444
        )

)

In result I need tree structure with ul and li elements:

<ul>
 <li>111</li>
 <li>222
  <ul>
   <li>333
   <ul>
    <li>444</li>
   </ul>
   </li>
  </ul>
 </li>
</ul>

Thanks!

Answer 1

This array looks a lot like you got it from a database. If that's the case, please just use an MVC framework. It will make your life so much easier.

Answer 2

<?php

$input_array = array(
    array(
        'categoryID' => 1,
        'parent' => 1,
        'name' => 111,
    ),
    array(
        'categoryID' => 2,
        'parent' => 1,
        'name' => 2222,
    ),
    array(
        'categoryID' => 3,
        'parent' => 2,
        'name' => 3333,
    ),
    array(
        'categoryID' => 4,
        'parent' => 3,
        'name' => 444,
    )
);

function buildHtmlList($array)
{
    $maxlevel = 0;

    // just to be sure that the array keys are continuous
    $array = array_values($array);

    foreach ($array as $key => $value)
    {
        $previousparent = isset($array[$key - 1]['parent']) ? $array[$key - 1]['parent'] : null;
        $nextparent = isset($array[$key + 1]['parent']) ? $array[$key + 1]['parent'] : null;

        if ($value['parent'] != $previousparent)
        {
            echo "\n<ul>";
            ++$maxlevel;
        }

        echo "\n<li>" . $value['name'];

        if ($nextparent == $value['parent'])
            echo "</li>";
    }

    for ($i = 0; $i < $maxlevel; ++$i)
    {
        echo "\n</li>\n</ul>";
    }
}

buildHtmlList($input_array);