/**     * 无限极分类     * @param $arr  所有分类     * @param $pid     * @param $step     * @return array     */    public function getTree($arr,$pid,$step){        global $tree;        foreach($arr as $key=>$val) {            if($val['cid'] == $pid) {                $flg = str_repeat("└--",$step);                $val['title'] = $flg.$val['title'];                $tree[] = $val;                $this->getTree($arr , $val['id'] ,$step+1);            }        }        return $tree;    }+    /**+     * 获取该栏目的所有子栏目ids+     * @param $id+     * @param $ids+     * @return array+     * @author 宁佳兵 
    
     +     */+    public function getChild($id, &$ids)+    {+        $res = D("article_category")->where(["parent_id"=>$id])->select();+        if (is_array($res)){+            foreach ($res as $k=>$v){+                $ids[] = $v['id'];+                $this->getChild($v['id'],$ids);+            }+        }+        return $ids;+    }