分享一个php实现无限级分类程序代码

无限级分类是所有程序开发中会碰到的一个问题，下面我来介绍php+mysql实现的一个无限级分类程序，有需要的朋友可参考参考。

下面给大家看看我的数据库结构吧：数据库的名字为：fa_category

Field	Type	Comment
cid	int(11)	分类id
catename	varchar(255)	分类名字
catetype	int(1)	分类类型，1为单页面，2为普通分类
catdir	varchar(255)	英文目录
display	int(1)	1为显示，2为不显示
keywords	varchar(255)	栏目关键字
description	text	栏目描述
ctime	int(11)	创建时间
parentid	int(11)	父节点id，最高节点父节点为0

     我们使用一个parentid字段来记录父节点的id，如果parentid为0，则为root。不多说，我们看看代码怎么写吧。我们要实现的功能就是如图片所示：

              

   怎么样把它这样显示呢？这个问题我想了很久，先看看这段SQL语句吧，

代码如下	复制代码
SELECT c.cat_id, c.cat_name, c.measure_unit, c.parent_id, c.is_show, c.show_in_nav, c.grade         ,c.sort_order, COUNT( s.cat_id ) AS has_children FROM ecs_category AS c LEFT JOIN ecs_category AS s ON s.parent_id = c.cat_id GROUP BY c.cat_id ORDER BY c.parent_id, c.sort_order ASC

 用左连接连接一个表，返回一个字段 has_children,这个字段是记录有多少子节点。

   看看代码吧，

代码如下

复制代码

public function getCategory($catid=0,$re_type = true,$selected=0)     {         $db      =  new Public_DataBase();         $sql  =  'select c.cid,c.catename,c.catetype,c.ctime,c.parentid,count(s.cid) as has_children from '.         __MYSQL_PRE.'category as c left join '.         __MYSQL_PRE.'category as s on s.parentid=c.cid group by c.cid order by c.parentid asc';         $res          =  $db->selectTable($sql);         $cateInfo     =    self::getChildTree($catid,$res);         if($re_type==true)         {                $select   =    '';               foreach($cateInfo as $val)               {                  $select .= '                  $select .= ($selected == $val['cid']) ? "selected='ture'" : '';                  $select .= '>';                   if($val['level']>0)                   {                             $select .= str_repeat(' ', $val['level'] * 4);                   }                   $select .= htmlspecialchars(addslashes($val['catename']), ENT_QUOTES) . '';               }               return $select;         }                 else         {             foreach($cateInfo as $key=>$val)             {                   if($val['level']>0)                   {                                     $cateInfo[$key]['catename']    =    "|".str_repeat(' ', $val['level'] * 8)."└─".$val['catename'];                                             }             }             return $cateInfo;         }                     }         /**      * 通过父ID递归得到所有子节点树      * @param int $catid  上级分类      * @param array $arr  含有所有分类的数组      * @return array      */     public function getChildTree($catid,$arr)     {         $level = $last_cat_id = 0;         while (!empty($arr))         {             foreach($arr as $key=>$value)             {                 $cid     =  $value['cid'];                 if ($level == 0 && $last_cat_id == 0)                 {                    if ($value['parentid'] > 0)                    {                        break;                    }                    $options[$cid]          =     $value;                    $options[$cid]['level'] =     $level;                    $options[$cid]['id']    =     $cid;                    $options[$cid]['name']  =     $value['catename'];                    unset($arr[$key]);                    if ($value['has_children'] == 0)                    {                         continue;                    }                    $last_cat_id  = $cid;                    $cat_id_array = array($cid);                    $level_array[$last_cat_id] = ++$level;                    continue;                      }                 if ($value['parentid'] == $last_cat_id)                 {                         $options[$cid]          = $value;                         $options[$cid]['level'] = $level;                         $options[$cid]['id']    = $cid;                         $options[$cid]['name']  = $value['catename'];                         unset($arr[$key]);                         if ($value['has_children'] > 0)                         {                             if (end($cat_id_array) != $last_cat_id)                             {                                 $cat_id_array[] = $last_cat_id;                             }                                 $last_cat_id    = $cid;                                 $cat_id_array[] = $cid;                                 $level_array[$last_cat_id] = ++$level;                         }                 }                 elseif ($value['parentid'] > $last_cat_id)                 {                     break;                 }             }                          $count = count($cat_id_array);              if ($count > 1)              {                  $last_cat_id = array_pop($cat_id_array);                               }              elseif ($count == 1)              {                if ($last_cat_id != end($cat_id_array))                {                    $last_cat_id = end($cat_id_array);                }                else                {                     $level = 0;                     $last_cat_id = 0;                     $cat_id_array = array();                     continue;                }              }              if ($last_cat_id && isset($level_array[$last_cat_id]))              {                 $level = $level_array[$last_cat_id];              }              else              {                  $level = 0;              }         }                     return $options;

    }用smarty的一个循环就可以把它显示出来 效果和上面图片的一样!大家有什么问题可以给我留言。