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('    ', $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。