TP3.2实现上下篇切换

<span>{$v.a_content}</span><a href="{$v.a_writer}?id={$v.a_id}">阅读详细</a></p></p></section>

<? 
 //新闻内
    public function index04(){        
        $this->ff();        
        $idds = I('get.id');             
            //上一篇
        $shang = M('article')->where("a_id <$idds and a_keyword=489")->order('a_id desc')->limit('1')->find();//查数据
            if($shang){//              判断如果执行成功往前面扔
        $this->assign('shang',$shang);

       }       
       else{//         否则让他的标题等于暂无吧
            $shang['a_title'] = "暂无";            
            $this->assign('shang',$shang);
        }        
//      下一篇
//同上
             $xia = M('article')->where("a_id >$idds and a_keyword=489")->order('a_id asc')->limit('1')->find();         
         if($xia){        
             $this->assign('xia',$xia);

       }       
       else{            
           $xia['a_title'] = "暂无";            
           $this->assign('xia',$xia);
        }        
        
           $this->display('jiu:public/7-6newsview');
     }

  <span class="prev">上一篇：<A href="{$shang.a_writer}?id={$shang.a_id}">{$shang.a_title}</A></span>
           <span class="next">下一篇：<A href="{$xia.a_writer}?id={$xia.a_id}">{$xia.a_title}</A></span>