using shared preferences on AsyncTask class for display data

Question

I'm stuck here.The problem is i have to access a SharedPreferences value and need it in an AsyncTask class. How i can access it in My AsyncTask ?. I need it for display data in JSON. When I try to acces it, "JSON parsing error : No Value lokasi" This is my code to take shared preferences. I wan't to display with the following code :

private String email = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        dataList = new ArrayList<>();
        //lv = (ListView) findViewById(R.id.list);

        //Fetching email from shared preferences
        SharedPreferences sharedPreferences = getSharedPreferences(Config.SHARED_PREF_NAME, Context.MODE_PRIVATE);
        String email = sharedPreferences.getString(Config.EMAIL_SHARED_PREF,"Not Available");
        //new GetEmail(email);
        new GetContacts().execute(email);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.

This is my code to get data JSON. I wan't to display with the following code :

 private class GetContacts extends AsyncTask<String, Void, Void> {

        @Override
        protected Void doInBackground(String... params) {
            HttpHandler sh = new HttpHandler();
            String email = params[0]; //WHAT NOW ?

            // Making a request to url and getting response
            String url = "http://192.168.43.176/GOLearn/lokasi.php?imei="+email;
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);
            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    JSONArray contacts = jsonObj.getJSONArray("lokasi");

                    // looping through All Contacts
                    for (int i = 0; i < contacts.length(); i++) {
                        JSONObject c = contacts.getJSONObject(i);
                        String id = c.getString("id");
                        String name = c.getString("name");
                        String latitude = c.getString("latitude");
                        String longitude = c.getString("longitude");


                        // tmp hash map for single contact
                        HashMap<String, String> map = new HashMap<>();

                        // adding each child node to HashMap key => value
                        map.put("id", id);
                        map.put("name", name);
                        map.put("latitude", latitude);
                        map.put("longitude", longitude);
                        //contact.put("mobile", mobile);

                        // adding contact to contact list
                        dataList.add(map);
                    }
                } 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;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            Toast.makeText(MapsActivity.this, "Json Data is downloading", Toast.LENGTH_LONG).show();
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);

            for (int x = 0; x < dataList.size(); x = x + 1) {
                double latasal = Double.parseDouble(dataList.get(x).get("latitude"));
                double longasal = Double.parseDouble(dataList.get(x).get("longitude"));
                LatLng posisi = new LatLng(latasal, longasal);
                String nama = dataList.get(x).get("name");

                mMap.addMarker(new MarkerOptions()
                        .position(posisi)
                        .title(nama)
                        .icon(BitmapDescriptorFactory.fromResource(R.drawable.min_marker))
                );

                mMap.moveCamera(CameraUpdateFactory.newLatLng(posisi));

            }
        }
    }

This my php code :

<?php
mysql_connect("localhost","root","");
mysql_select_db("db_golearn");

$id = $_REQUEST['imei'];

$query="select * from lokasi where id='$id'";
$hasil=mysql_query($query);
if(mysql_num_rows($hasil) > 0) {

    $response = array();
    $response["lokasi"] = array();

    while ($data = mysql_fetch_array($hasil)) {
        $h['id']= $data['id'];
        $h['name']= $data['name'];
        $h['latitude']= $data['latitude'];
        $h['longitude']= $data['longitude'];
        $h['imei']= $data['imei'];

        array_push($response["lokasi"], $h);
    }

    $response["success"] = "1";
    echo json_encode($response);
}
else {
    $response["success"]=0;
    $response["message"]="Tidak ada data";

    echo json_encode($response);
}
?>

Please help

Answer 1

I cant comment on your question.So i am asking here. @Intan Iryanti:-where is your problem?.Where you want to use shared preference?

add the following constructor in your async task

private class GetContacts extends AsyncTask<String, Void, Void> {
SharedPreferences sharedPreferences;
      public GetContacts(SharedPreferences sharedPreferences)
{
this.sharedPreferences= sharedPreferences;
}

@Override

protected Void doInBackground(String... params) { HttpHandler sh = new HttpHandler(); String email = sharedPreferences.getString(Config.EMAIL_SHARED_PREF,"Not Available");

    // Making a request to url and getting response
    String url = "http://192.168.43.176/GOLearn/lokasi.php?imei="+email;
    String jsonStr = sh.makeServiceCall(url);

...

... }

call async task as follow

GetContacts getContacts=new getContacts(sharedPreferences);
getContacts.execute();

Answer 2

Cant comment (don't have enough reputations), so asking it here.

Are you sure that the error you are talking about JSON parsing error : No Value lokasi is related to the SharedPreferences ?

You are, in your code giving the email as an argument to the method:

....
@Override
protected Void doInBackground(String... params) {
        HttpHandler sh = new HttpHandler();
        String email = params[0]; // This line means that the email was
                                  // in the params
....

so, I think the error is not being caused by the sharedPreferences, but cause of the JSON object that the code is receiving.

You are trying to access the lokasi object in the JSON :

 ....
 ....
 // Getting JSON Array node
 JSONArray contacts = jsonObj.getJSONArray("lokasi");
 ....
 ....

are you sure that it exists there ? Try to print out the jsonstring

Lod.d("GetContacts","the json string: "+ jsonStr); 

EDIT

Also, please check if the email variable inside the doInBackground() is what you want it to be. That can be the cause, why your httpRequest isn't replying with what you want it to. You can check your email variable again by using :

Log.d("GetContacts"."email : "+email);

Answer 3

Usually AsyncTask should not be complicated. Internally it is the thread and We use a thread only for specific task, so keep it as simple as possible and specific to that single task only.

If you want shared preferences values inside AsyncTask, pass those as parameters. It is simple and modular.