在php codeigniter中显示Flash数据

I am struggling with flash data in codeigniter. My edit function is working properly. But problem is with delete function.My controller is as follows

public function rmRole() 
{

    $data = array();
    $roleId = $this->uri->segment(4,0);

    if ($this->_delete($roleId)) {
        $this->session->set_flashdata('flash_message' ,'data_deleted');
        redirect('adminroles');
    }
}

My model includes

public function _delete($id) {

    $table = $this->get_table();
    $this->db->where('id', $id);

    $this->db->delete($table);

}

My data is got deleted. But it is redirecting to a blank page with the url. What shall i do to display a flash data like data deleted successfully and redirect to adminroles module?

try this in model

function delete($id) {
   if ($id) 
   {      
      if ($this->db->where("id", $id)->delete("table name")){
          return TRUE;
      }
      else{ 
          return FALSE;
      }
   }else{ 
          return FALSE;
   }
}