PHP递归实现层级树状展开

本文实例为大家分享了PHP递归实现层级树状展开的主要代码，供大家参考，具体内容如下

效果图：

实现代码：

<?php

$db = mysql_connect('localhost', 'root', 'root') or die('Can\'t connect to database');
mysql_select_db('test') or die('Can\'t find database : test');
$result = mysql_query('select id, fid, name from tree');
while($arr = mysql_fetch_array($result)){
  $data[] = array(
    'id' => $arr['id'],
    'fid' => $arr['fid'],
    'name' => $arr['name'],
  );
}

// 将数据按照缩进简单排列 见图1
function data2arr($tree, $rootId = 0, $level = 0) {
  foreach($tree as $leaf) {
    if($leaf['fid'] == $rootId) {
      echo str_repeat('&nbsp;&nbsp;&nbsp;&nbsp;', $level) . $leaf['id'] . ' ' . $leaf['name'] . '<br/>';
      foreach($tree as $l) {
        if($l['fid'] == $leaf['id']) {
          data2arr($tree, $leaf['id'], $level + 1);
          break;
        }
      }
    }
  }
}

data2arr($data);
echo '<br/>-----------------------------------------------------------------------<br/>';

// 将数据按照所属关系封装 见图2
function arr2tree($tree, $rootId = 0) {
  $return = array();
  foreach($tree as $leaf) {
    if($leaf['fid'] == $rootId) {
      foreach($tree as $subleaf) {
        if($subleaf['fid'] == $leaf['id']) {
          $leaf['children'] = arr2tree($tree, $leaf['id']);
          break;
        }
      }
      $return[] = $leaf;
    }
  }
  return $return;
}

$tree = arr2tree($data);
print_r($tree);
echo '<br/>-----------------------------------------------------------------------<br/>';

// 将数据使用HTML再次展现 见图3
function tree2html($tree) {
  echo '<ul>';
  foreach($tree as $leaf) {
    echo '<li>' .$leaf['name'];
    if(! emptyempty($leaf['children'])) tree2html($leaf['children']);
    echo '</li>';
  }
  echo '</ul>';
}

tree2html($tree);

以上就是本文的全部内容，希望对大家学习php程序设计有所帮助。