Populating a ListView via a php script in Android app using AsyncTask

This class retrieves JSON data from a PHP script and uses the data to populate a ListView using AsyncTasks. Any ideas on how to improve it?

public class MainActivity extends ActionBarActivity {

    ArrayList<Location> arrayOfLocations;
    LocationAdapter adapter;

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

        // Construct the data source
        arrayOfLocations = new ArrayList<Location>();

        // Create the adapter to convert the array to views
        adapter = new LocationAdapter(this, arrayOfLocations);

        FillLocations myFill = new FillLocations();
        myFill.execute();

    }

        //this class downloads an image and passes that (and other data) into an
        //adapter which populates the ListView
    class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {
        private int photoID = 1;
        JSONObject json = null;

        public BitmapWorkerTask(int photoID, JSONObject json) {
            // Use a WeakReference to ensure the ImageView can be garbage
            // collected
            this.photoID = photoID;
            this.json = json;
        }

        protected void onPreExecute() {

        }

        // Decode image in background.
        @Override
        protected Bitmap doInBackground(Integer... params) {
            String initialURL = "http://afs.spotcontent.com/img/Places/Icons/";
            final String updatedURL = initialURL + photoID + ".jpg";
            Bitmap bitmap2 = null;

            try {
                bitmap2 = BitmapFactory.decodeStream((InputStream) new URL(
                        updatedURL).getContent());

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

            return bitmap2;
        }

        // Once complete, see if ImageView is still around and set bitmap.
        @Override
        protected void onPostExecute(Bitmap bitmap2) {
            try {
                adapter.add(new Location(bitmap2, json.getString("PlaceTitle"),
                        json.getString("PlaceDetails"), json
                                .getString("PlaceDistance"), json
                                .getString("PlaceUpdatedTime")));
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
    }

        //this class retrieves the JSON data from the PHP script
        //and parses it, then it calls the Bitmap task to get the
        //image and then add the location
    private class FillLocations extends AsyncTask<Integer, Void, String> {

        protected void onPreExecute() {
        }

        // Decode image in background.
        @Override
        protected String doInBackground(Integer... params) {

            String result = "";
            InputStream isr = null;
            try {
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost("http://myscript.php/"); // YOUR
                                                                                    // PHP
                                                                                    // SCRIPT
                                                                                    // ADDRESS
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity entity = response.getEntity();
                isr = entity.getContent();
                // resultView.setText("connected");
            } catch (Exception e) {
                Log.e("log_tag", "Error in http connection " + e.toString());
            }
            // convert response to string
            try {
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(isr, "iso-8859-1"), 8);
                StringBuilder sb = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {
                    sb.append(line + "\n");
                }
                isr.close();

                result = sb.toString();
            } catch (Exception e) {
                Log.e("log_tag", "Error  converting result " + e.toString());
            }

            // parse json data
            try {
                JSONArray jArray = new JSONArray(result);

                for (int i = 0; i < jArray.length(); i++) {
                    final JSONObject json = jArray.getJSONObject(i);
                    counter++;

                    try {

                        BitmapWorkerTask myTask = new BitmapWorkerTask(
                                json.getInt("ID"), json);
                        myTask.execute();

                    } catch (JSONException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                }

            } catch (Exception e) {
                // TODO: handle exception
                Log.e("log_tag", "Error Parsing Data " + e.toString());
            }
            return msg;

        }

        protected void onPostExecute(String msg) {
            // Attach the adapter to a ListView
            ListView listView = (ListView) findViewById(R.id.listView1);

            listView.setAdapter(adapter);

        }
    }
}