CI框架分页（不解错误）

Controller:

        function __construct()
        {
                parent::__construct();
                $this->load->library('page_smart');
                $this->load->model('Admin/user_index_data');
                $this->load->helper('url');
        }

        //用户列表
        function user_list()
        {
                $data['user_list']=$this->user_index_data->select_user();
                $this->load->view('AdminLogin/user_index/user_list',$data);
        }

        //角色列表
        function role_list($page)
        {
                $config['page']=$page;
                $config['rows']=1;
                $config['pagenav']=null;
                $config['page_size']=$this->user_index_data->select_role_sum();
                $page_rst=$this->page_smart->page_do($config);
                $data['role_list']=$this->user_index_data->select_role($page_rst['select_from'],$page_rst['select_limit']);
                $data['page_list']=$page_rst['pagenav'];
                $this->load->view('AdminLogin/user_index/role_list',$data);
        }

Model:

    function __construct()
    {
        //装载日期辅助函数
        $this->load->helper('date');
        //装载数据库函数
        $this->load->database();
    }

    /*********************
        查询数据部分

    **********************/

    //查询所有用户数据
    function select_user(){
        $query=$this->db->query("select id,useranme,password,name,email,mobile_phone,(select role_name from w3a_role where role_id=purview) purview from w3a_user");
        return $query->result_array();
    }
    
    //查询所有的角色数据
    function select_role($total,$offset){
        $sql="select * from w3a_role limit $total,$offset";
        $query=$this->db->query($sql);
        return $query->result_array();
    }
    
    function select_role_sum(){
        $query=$this->db->get('w3a_role');
        return $query->num_rows();
    }

分页类：

<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');

class Page_smart{
       public function Page_do($config = array())
       {
                if (count($config) > 0)
                {
                        foreach ($config as $key => $val)
                        {
                                if (isset($this->$key))
                                {
                                        $this->$key = $val;
                                }
                        }
                }
                $page=$config['page'];
                $page_size=$config['page_size'];
                $pagenav=$config['pagenav'];
                $rows=$config['rows'];
                $page_count = ceil($rows/$page_size);
                if($page <= 1 || $page == '') $page = 1;
                  if($page >= $page_count) $page = $page_count;
                  $select_limit = $page_size;
                  $select_from = ($page - 1) * $page_size;
                  $pre_page = ($page == 1)? 1 : $page - 1;
                  $next_page= ($page == $page_count)? $page_count : $page + 1 ;
                  $pagenav .="<div class='pagination pagination-right'>";
                  $pagenav .="<ul><li><a href='1'>«</a></li>";
                  for($i=1;$i<=$page_count;$i++){
                        if($i==$page)
                        {
                                 $pagenav.="<li><a href='$i'>$i</a></li>";
                        }
                        else
                        {
                                $pagenav.="<li><a href='$i'>$i</a></li>";
                        }
                }
                $pagenav .= "<li><a href='$i'>»</a></li><ul></div>";
                $page_result['pagenav']=$pagenav;
                $page_result['select_limit']=$select_limit;
                $page_result['select_from']=$select_from;
                return $page_result;
         }
}
/* End of file Someclass.php */
~                                                         

求解释。。。