java - 如何从php获取json的COUNT(id)值到android

Question

当我尝试获取数据库的 Count(id) 值时，出现错误。我想获取该值并将他放入textView中。

这是我的java代码(响应已经构造为数组)

public  void  test3(View rootView){ 

   String result = null;

    try
    {
        tv = (TextView) rootView.findViewById(R.id.textView);
        RequestQueue queue = Volley.newRequestQueue(getActivity().getApplicationContext());

        String url = "http://brunos.000webhostapp.com/teste/listar_divisoes.php";

        final String finalResult = result;
        JsonArrayRequest jsonRequest = new JsonArrayRequest
                (Request.Method.GET, url, null, new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        try {
                            JSONObject jObj = new JSONObject(finalResult);
                            String count= jObj.getString("COUNT(id)");
                            tv.setText(count);
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                }, new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        error.printStackTrace();
                    }
                });
        queue.add(jsonRequest);
    }

这是我的 php 代码:

<?php
include 'database.php';
$pDatabase = Database::getInstance();
$sql = "SELECT COUNT(id) FROM divisao;";
$result = $pDatabase->query($sql);
$rows = array();
    while($temp = mysqli_fetch_assoc($result)) {
        $rows[] = $temp;
}
    echo json_encode($rows);
?>

Answer 1

您没有读取 JSONArray 响应对象:

 public void onResponse(JSONArray response) {
    try {
             JSONObject jObj = new JSONObject(finalResult);
             String count= jObj.getString("COUNT(id)");
             tv.setText(count);
    } catch (JSONException e) {
         e.printStackTrace();
    }

}

应该是:

 public void onResponse(JSONArray response) {
    try {
             JSONObject jObj = new JSONObject(response.get(0));
             String count= jObj.getString("COUNT(id)");
             tv.setText(count);
    } catch (JSONException e) {
         e.printStackTrace();
    }

}