REST GET from android to DRUPAL with a simple LISTVIEW

MainActivity.java

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;


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

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


public class MainActivity extends AppCompatActivity {


    ListView listado;

    public static String [] nombres = {
            "Let Us C",
            "c++",
            "JAVA",
            "Jsp",
            "Microsoft .Net",
            "Let Us C",
            "c++",
            "JAVA",
            "Jsp",
            "Microsoft .Net",
            "Microsoft .Net",
            "Microsoft .Net",
    };

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

        // call AsynTask to perform network operation on separate thread
        new getData().execute("http://dev-edutrul.pantheon.io/ws/eventos-ws.json");
    }
    public class getData extends AsyncTask<String, String, String> {

        HttpURLConnection urlConnection;

        @Override
        protected String doInBackground(String... args) {

            StringBuilder result = new StringBuilder();

            try {
                URL url = new URL(args[0]);
                urlConnection = (HttpURLConnection) url.openConnection();
                InputStream in = new BufferedInputStream(urlConnection.getInputStream());

                BufferedReader reader = new BufferedReader(new InputStreamReader(in));

                String line;
                while ((line = reader.readLine()) != null) {
                    result.append(line);
                }

            }catch( Exception e) {
                e.printStackTrace();
            }
            finally {
                urlConnection.disconnect();
            }


            return result.toString();
        }

        @Override
        protected void onPostExecute(String result) {

            //Do something with the JSON string
            Toast.makeText(getBaseContext(), "Received!", Toast.LENGTH_LONG).show();
            System.out.println(result);
            try {
                JSONArray contenidos = new JSONArray(result); // get articles array
                System.out.println(contenidos);
                String titulos[];
                titulos = new String[contenidos.length()];
                for (int i = 0; i < contenidos.length(); i++) {
                    System.out.println(contenidos.getJSONObject(i).get("title"));
                    titulos[i] = contenidos.getJSONObject(i).get("title").toString();
                }

                listado=(ListView) findViewById(R.id.listado);
                ArrayAdapter<String> adapter = new ArrayAdapter<String>(MainActivity.this,
                        android.R.layout.simple_list_item_1, titulos);
                listado.setAdapter(adapter);

            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

    }
}