Conectar a base de datos aplic Android.

package com.example.conexionbd;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Tarea a = new Tarea();
    a.execute();

}

private class Tarea extends AsyncTask<Void, Integer, Boolean> {

    @Override
    protected Boolean doInBackground(Void... arg0) {
        // TODO Auto-generated method stub
        conectarBd();
        return true; 
    }

    public void conectarBd() {

        Connection conn = null;
        String url = "jdbc:mysql://10.0.2.2/";
        String dbName = "pruebas";
        String driver = "com.mysql.jdbc.Driver";
        String userName = "pruebas";
        String password = "1234";
        String resultado;
        Log.i("iniciando", "iniciando");
        try {

            Class.forName(driver).newInstance();
            conn = DriverManager.getConnection(url + dbName, userName,
                    password);
            Log.i("Conectado", "Conectadito");

            Statement st = (Statement) conn.createStatement();
            ResultSet rs = st.executeQuery("select usuario from usuarios");

            while (rs.next()) {

                resultado = rs.getString("usuario");
                Log.i("usuario", resultado);

            }

            conn.close();
        } catch (Exception e) {
            Log.i("error", "error");
            Log.i("olakase", e + "");
        }

    }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}