How to show nearby locations from current location android studio?

I have been trying to display nearby locations from my current location. But when i run it and click the button to view the nearby locations nothing appears. The first time i ran it, it displayed but when i backed out and came back in, it didnt display anything. i tried cleaning the project and other methods.

this is the method in my main class:

public void findRestaurants(View v){
        StringBuilder stringBuilder = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
        stringBuilder.append("location="+latLngCurrent.latitude + "," +latLngCurrent.longitude);
        stringBuilder.append("&radius="+5000);
        stringBuilder.append("&keyword="+"restaurant");
        stringBuilder.append("&key="+getResources().getString(R.string.google_map_keyy));

        String url = stringBuilder.toString();

        Object dataTransfer[] = new Object[2];
        dataTransfer[0] = mMap;
        dataTransfer[1] = url;

        getNearbyPlaces getnearbyPlaces = new getNearbyPlaces();
        getnearbyPlaces.execute(dataTransfer);



    }




public class getNearbyPlaces extends AsyncTask<Object,String,String> {
   GoogleMap mMap;
   String url;
   InputStream is;
   BufferedReader  bufferedReader;
   StringBuilder stringBuilder;
   String data;
    @Override
    protected String doInBackground(Object... objects) {
        mMap = (GoogleMap)objects[0];
        url = (String)objects[1];

        try {
            URL myurl = new URL(url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) myurl.openConnection();
            httpURLConnection.connect();
            is = httpURLConnection.getInputStream();
            bufferedReader = new BufferedReader(new InputStreamReader(is));

            String line = "";
            stringBuilder = new StringBuilder();

            while((line = bufferedReader.readLine() ) != null){
                stringBuilder.append(line);
            }
            data = stringBuilder.toString();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return data;
    }

    @Override
    protected void onPostExecute(String s) {

        try {
            JSONObject parentObject = new JSONObject(s);
            JSONArray resultsArray = parentObject.getJSONArray("results");

            for (int i = 0; i<resultsArray.length(); i++){
                JSONObject jsonObject = resultsArray.getJSONObject(i);
                JSONObject locationObj = jsonObject.getJSONObject("geometry").getJSONObject("location");

                String latitude = locationObj.getString("lat");
                String longitude = locationObj.getString("lng");

                JSONObject nameObject = resultsArray.getJSONObject(i);
                String name_restaurant =  nameObject.getString("name");
                String vicinity = nameObject.getString("vicinity");

                LatLng latLng = new LatLng(Double.parseDouble(latitude),Double.parseDouble(longitude));

                MarkerOptions markeroptions = new MarkerOptions();
                markeroptions.title(vicinity);
                markeroptions.position(latLng);

                mMap.addMarker(markeroptions);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

it worked the first time when i lunched it. Did i do something wrong?