Hosting - Why my database not auto update when i edit the value?

Question

i create an app in android to displaying value of table, then i create database in hosting,

and this is the link for displaying my table,

and this script for select an output of my table,

send_data.php

<?php
header('Content-type:application/json;charset=utf-8');
include 'dbconfig.php';
$con = new mysqli($servername, $username, $password, $dbname);
if (mysqli_connect_errno()) {
   echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$query = "select id,ask from pertanyaan";
$result = mysqli_query($con, $query);
while ($r = mysqli_fetch_array($result)) {
   extract($r);
$rows[] = array(
    "id"    => $id,
    "ask"   => $ask
  );
}
echo json_encode($rows);
mysqli_close($con);
?>

but when i change the value in table, my application does not automatically update when I reopen the app, However, its application can be updated when I visit the link to display,

additional information :

this is my android code

MainActivity.java

package flix.yudi.okhttp1;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.RatingBar;
import android.widget.SimpleAdapter;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity extends AppCompatActivity {

    private String TAG = MainActivity.class.getSimpleName();

    private ProgressDialog pDialog;
    private ListView lv;
    RatingBar rb1;

    // URL to get contacts JSON
//    private static String url = "http://www.mocky.io/v2/580dd704120000b70a078702";
    private static String url = "http://zxccvvv.netne.net/send_data.php";

    ArrayList<HashMap<String, String>> contactList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        contactList = new ArrayList<>();
        lv = (ListView) findViewById(R.id.list);
        new GetContacts().execute();
    }

    /**
     * Async task class to get json by making HTTP call
     */
    private class GetContacts extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }

        @Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);

            if (jsonStr != null) {
                try {
                    JSONArray jsonObj = new JSONArray(jsonStr);

                    // looping through All Contacts
                    for (int i = 0; i < jsonObj.length(); i++) {
                        JSONObject c = jsonObj.getJSONObject(i);

                        String id = c.getString("id");
                        String ask = c.getString("ask");

                        HashMap<String, String> pertanyaans = new HashMap<>();

                        pertanyaans.put("id", id);
                        pertanyaans.put("ask", ask);

                        contactList.add(pertanyaans);
                    }
                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }
            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG)
                                .show();
                    }
                });

            }

            return null;
        }
//        public class MainActivity extends Activity implements OnRatingBarChangeListener {
//        RatingBar ratingBar;
//
//        @Override
//        protected void onCreate(Bundle savedInstanceState) {
//            super.onCreate(savedInstanceState);
//            setContentView(R.layout.activity_main);
//            ((RatingBar) findViewById(R.id.ratingBar1)).setOnRatingBarChangeListener(this);
//        }
//
//        @Override
//        public void onRatingChanged(RatingBar ratingBar, float rating,boolean fromTouch) {
//            final int numStars = ratingBar.getNumStars();
//            // set here your link
//            String serverlink = "";
//            if(numStars == 4)
//            {
//                serverlink = "http://www.example.com/4star.php";
//            }
//            else if(numStars == 5)
//            {
//                serverlink = "http://www.example.com/5star.php";
//            }
//
//            // now send link to server which is stored in serverlink object
//        }
//    }
//
//        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, contactList,
                    R.layout.list_item, new String[]{"ask"}, new int[]{R.id.ask});

            lv.setAdapter(adapter);
        }

    }
}

HttpHandler.java

package flix.yudi.okhttp1;

import android.util.Log;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;

public class HttpHandler {

    private static final String TAG = HttpHandler.class.getSimpleName();

    public String makeServiceCall(String reqUrl) {
        String response = null;
        try {
            URL url = new URL(reqUrl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setConnectTimeout(7000);
            conn.setRequestMethod("GET");
            // read the response
            InputStream in = new BufferedInputStream(conn.getInputStream());
            response = convertStreamToString(in);
        } catch (MalformedURLException e) {
            Log.e(TAG, "MalformedURLException: " + e.getMessage());
            e.printStackTrace();
        } catch (ProtocolException e) {
            Log.e(TAG, "ProtocolException: " + e.getMessage());
            e.printStackTrace();
        } catch (IOException e) {
            Log.e(TAG, "IOException: " + e.getMessage());
               e.printStackTrace();
        } catch (Exception e) {
            Log.e(TAG, "Exception: " + e.getMessage());
            e.printStackTrace();
        }
        return response;
    }

    private String convertStreamToString(InputStream is) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line).append('\n');
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}