CI 笔记7，easyui 异步加载

在做后台导航时，需要异步加载，pid和id的循环问题，在controller中，建立另外一个方法，嵌套循环，查找是否pid〉1。

    public function nav_list()
    {
        $this->load->database();
        /*
        测试demo json传值
        $query = $this->db->query('select nav_name,nav_desc from nav');
        $row = $query->result_array();
        $json = json_encode($row);
        echo $json;
        */

        /**
         * 异步加载
         */    

        $id = isset($_POST['id']) ? intval($_POST['id']) : 0;
        $result = array();
        $query = $this->db->query("select id,nav_name,nav_desc,pid from nav where pid =$id");
        foreach($query->result_array() as $row)
        {
            $node = array();
            $node['id'] = $row['id'];
            $node['text'] = $row['nav_desc'];
            $node['state'] = $this->has_child($row['id']) ? 'closed' : 'open';
            array_push($result,$node);
        }    

        echo json_encode($result);

    }

    public function has_child($id)
    {
        $this->load->database();
        $query = $this->db->query("select pid from nav where pid=$id");
        $row = $query->num_rows();
        return $row > 1 ? true : false;
    }

html代码为：

        <!-- 导航 -->

        <ul id="nav"  class="easyui-tree"  url="nav_list">

        </ul>