随机生成的问题不会在Android应用工作

Question

answered_questions：

问题：

我有这些表和下面的PHP脚本

if($_SERVER['REQUEST_METHOD'] == 'GET') { 


//makes it work 
$category = (string)filter_input(INPUT_GET, 'category'); 
$game_id = (string)filter_input(INPUT_GET, 'game_id'); 

require_once('dbConnect.php'); 

$query = "SELECT question FROM questions 
    WHERE category = '$category' 
    and question 
    NOT IN 
    (SELECT question 
    FROM answered_questions 
    WHERE game_id='$game_id')ORDER BY Rand() limit 1"; 

$r = (mysqli_query($con, $query)); 

$res = mysqli_fetch_array($r); 

$result = array(); 

array_push($result, array(
     "question" => $res['question'], 
    ) 
); 

echo json_encode(array("result" => $result)); 

mysqli_close($con); 

} 

一切工作，直到我在android中运行应用程序。当我点击getQuestion按钮/调用方法时，该应用程序产生已经回答的问题。该应用旨在产生一个问题，是不是在与每个回答问题表点击

private void getQuestion() { 

    String url =""; 

    String cat = category.getText().toString(); 
    String id = game_id.getText().toString(); 

    if (cat.equals("Control Questions")){ 
     url = "http://192.168.0.20/Articulate/getControlQuestion.php?game_id="+id; 
    }else { 
     url = "http://192.168.0.20/Articulate/getQuestion.php?category="+cat+"&game_id="+id; 
    } 

    StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() { 
     @Override 
     public void onResponse(String response) { 
      showJSON(response); 
     } 
    }, 
      new Response.ErrorListener() { 
       @Override 
       public void onErrorResponse(VolleyError error) { 
       } 
      }); 

    RequestQueue requestQueue = Volley.newRequestQueue(this); 
    requestQueue.add(stringRequest); 
} 

private void showJSON(String response){ 
    String ques=""; 
    try { 
     JSONObject jsonObject = new JSONObject(response); 
     JSONArray result = jsonObject.getJSONArray(Config.JSON_ARRAY); 
     JSONObject collegeData = result.getJSONObject(0); 
     ques = collegeData.getString("question"); 
    } catch (JSONException e) { 
     e.printStackTrace(); 
    } 
    question.setText(ques); 
} 

Answer 1

你们为什么不干脆合并两个表，并添加一个布尔（TINYINT）字段answered？那么你只需要将你的SQL请求更改为SELECT question FROM questions WHERE category = '$category' AND answered = 0