php 无限级分类，超级简单的无限级分类，支持输出树状图

无平台限制 只需要告知id,parentid,name 即可

rush:PHP;"> class Tree
{

/**
+------------------------------------------------

• 生成树型结构所需要的2维数组
  +------------------------------------------------
• @author abc
  +------------------------------------------------
• @var Array
  */
  var $arr = array();

/**
+------------------------------------------------

• 生成树型结构所需修饰符号，可以换成图片
  +------------------------------------------------
• @author abc
  +------------------------------------------------
• @var Array
  */
  var $icon = array(' │',' ├',' └');

/**

• @access private
  */
  var $ret = '';

/**

• 构造函数，初始化类
• @param array 2维数组，例如：
• array(
• 1 => array('id'=>'1','parentid'=>0,'name'=>'一级栏目一'), 2 => array('id'=>'2','name'=>'一级栏目二'), 3 => array('id'=>'3','parentid'=>1,'name'=>'二级栏目一'), 4 => array('id'=>'4','name'=>'二级栏目二'), 5 => array('id'=>'5','parentid'=>2,'name'=>'二级栏目三'), 6 => array('id'=>'6','parentid'=>3,'name'=>'三级栏目一'), 7 => array('id'=>'7','name'=>'三级栏目二')
• )
  */
  function tree($arr=array())
  {
  $this->arr = $arr;
  $this->ret = '';
  return is_array($arr);
  }

/**

• 得到父级数组
• @param int
• @return array
  */
  function get_parent($myid)
  {
  $newarr = array();
  if(!isset($this->arr[$myid])) return false;
  $pid = $this->arr[$myid]['parentid'];
  $pid = $this->arr[$pid]['parentid'];
  if(is_array($this->arr))
  {
  foreach($this->arr as $id => $a)
  {
  if($a['parentid'] == $pid) $newarr[$id] = $a;
  }
  }
  return $newarr;
  }

/**

• 得到子级数组
• @param int
• @return array
  */
  function get_child($myid)
  {
  $a = $newarr = array();
  if(is_array($this->arr))
  {
  foreach($this->arr as $id => $a)
  {
  if($a['parentid'] == $myid) $newarr[$id] = $a;
  }
  }
  return $newarr ? $newarr : false;
  }

/**

• 得到当前位置数组
• @param int
• @return array
  */
  function get_pos($myid,&$newarr)
  {
  $a = array();
  if(!isset($this->arr[$myid])) return false;
  $newarr[] = $this->arr[$myid];
  $pid = $this->arr[$myid]['parentid'];
  if(isset($this->arr[$pid]))
  {
  $this->get_pos($pid,$newarr);
  }
  if(is_array($newarr))
  {
  krsort($newarr);
  foreach($newarr as $v)
  {
  $a[$v['id']] = $v;
  }
  }
  return $a;
  }

/**

• ---

• 得到树型结构

• ---

• @author abc
• @param $myid 表示获得这个ID下的所有子级
• @param $str 生成树形结构基本代码,例如: "<option value=\$id \$select>\$spacer\$name"
• @param $sid 被选中的ID,比如在做树形下拉框的时候需要用到
• @param $adds
• @param $str_group
  */
  function get_tree($myid,$str,$sid = 0,$adds = '',$str_group = '')
  {
  $number=1;
  $child = $this->get_child($myid);
  if(is_array($child)) {
  $total = count($child);
  foreach($child as $id=>$a) {
  $j=$k='';
  if($number==$total) {
  $j .= $this->icon[2];
  } else {
  $j .= $this->icon[1];
  $k = $adds ? $this->icon[0] : '';
  }
  $spacer = $adds ? $adds.$j : '';
  $selected = $id==$sid ? 'selected' : '';
  @extract($a);
  $parentid == 0 && $str_group ? eval("\$nstr = \"$str_group\";") : eval("\$nstr = \"$str\";");
  $this->ret .= $nstr;
  $this->get_tree($id,$sid,$adds.$k.'',$str_group);
  $number++;
  }
  }
  return $this->ret;
  }

/**

• 同上一方法类似,但允许多选
  */
  function get_tree_multi($myid,$adds = '')
  {
  $number=1;
  $child = $this->get_child($myid);
  if(is_array($child))
  {
  $total = count($child);
  foreach($child as $id=>$a)
  {
  $j=$k='';
  if($number==$total)
  {
  $j .= $this->icon[2];
  }
  else
  {
  $j .= $this->icon[1];
  $k = $adds ? $this->icon[0] : '';
  }
  $spacer = $adds ? $adds.$j : '';

  $selected = $this->have($sid,$id) ? 'selected' : '';
  @extract($a);
  eval("\$nstr = \"$str\";");
  $this->ret .= $nstr;
  $this->get_tree_multi($id,$adds.$k.'');
  $number++;

  }
  }
  return $this->ret;
  }

function have($list,$item){
return(strpos(','.$list.',','.$item.','));
}

/**
+------------------------------------------------

• 格式化数组
  +------------------------------------------------
• @author abc
  +------------------------------------------------
  */
  function getArray($myid=0,$sid=0,$adds='')
  {
  $number=1;
  $child = $this->get_child($myid);
  if(is_array($child)) {
  $total = count($child);
  foreach($child as $id=>$a) {
  $j=$k='';
  if($number==$total) {
  $j .= $this->icon[2];
  } else {
  $j .= $this->icon[1];
  $k = $adds ? $this->icon[0] : '';
  }
  $spacer = $adds ? $adds.$j : '';
  @extract($a);
  $a['name'] = $spacer.' '.$a['name'];
  $this->ret[$a['id']] = $a;
  $fd = $adds.$k.'';
  $this->getArray($id,$fd);
  $number++;
  }
  }

return $this->ret;

}
}

$data=array(
1 => array('id'=>'1',2 => array('id'=>'2',3 => array('id'=>'3',4 => array('id'=>'4',5 => array('id'=>'5',6 => array('id'=>'6',7 => array('id'=>'7','name'=>''),8 => array('id'=>'8','name'=>'三级栏目三'),9 => array('id'=>'9','parentid'=>7,'name'=>'四级分类三'),);
$tree = new Tree;
$tree->tree($data);

// 如果使用数组,请使用 getArray方法
//$tree->getArray();
// 下拉菜单选项使用 get_tree方法
$html='<select name="tree">';
$str = "<option value=\$id \$select>\$spacer\$name";
$html .= $tree->get_tree(0,-1).'';
echo $html;
?>