json数组没有被创建

Question

我认为使用以下代码jsonarray不会被包装。 因为我调试代码但似乎没有进入for循环。 我提供了PHP代码和android代码的一部分。 请帮我。

我在onPostExecute中编写了以下代码

      if (success == 1) {
            // Getting Array of users
            try{
            JSONArray users=json.getJSONArray(TAG_USERS);
            // looping through All Products
            for (int i = 0; i < users.length(); i++) {
                Log.d("check", "success");
                JSONObject c = users.getJSONObject(i);

                // Storing each json item in variable
                String name = c.getString(TAG_UNAME);
                Log.d("name....",name);
                usersList.add(name);
            }
        } catch(JSONException e)
        {
            e.printStackTrace();
        }
      }

这是php代码

<?php

$response = array();
// include db connect class
require_once __DIR__ . '/db_connect.php';

$db = new DB_CONNECT();
$result = mysql_query("SELECT *FROM userdetails") or die(mysql_error());

    if (mysql_num_rows($result) >0) {
    // looping through all results
            $response["users"] = array();   
    While($result = mysql_fetch_array($result))
    {
        $users = array();
        $users["uid"] = $result["uid"];
        $users["firstName"] = $result["firstName"];
        $users["lastName"] = $result["lastName"];
        $users["userName"] = $result["userName"];    
        array_push($response["users"], $users);
}
    // success
    $response["success"] = 1;

    // echoing JSON response
    echo json_encode($response);

        } else {
            $response["success"] = 0;
            $response["message"] = "No user found";

            // echo no users JSON
            echo json_encode($response);
        }
?>