public class MainActivity extends Activity {
private Button  boton1,
                boton2,
                boton3,
                boton4;
private String  valor;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    configuracion();
}
public void configuracion(){
    StrictMode.ThreadPolicy policy = new StrictMode.
            ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);
    establecerBotones();
    try{
    definir("continua/0/0");
    definir("direccion/0/0");
    }
    catch(Exception e){
        Alerta();
    }
}

public void establecerBotones(){
    boton1= (Button)findViewById(R.id.boton1);      //all buttons do something similar
    boton1.setOnTouchListener(new OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            int action = event.getAction();
            switch(action){
                case MotionEvent.ACTION_DOWN:
                    v.setPressed(true);
                    conectar("continua/1/0");
                    break;
                case MotionEvent.ACTION_OUTSIDE:
                case MotionEvent.ACTION_UP:
                    v.setPressed(false);
                    try {
                        conectar("continua/0/0");
                    } catch (Exception e) {
                    }
                    break;
            }
            return true;
        }
    });
    boton2= (Button)findViewById(R.id.boton2);
    boton2.setOnTouchListener(new OnTouchListener() {
    });
    boton3= (Button)findViewById(R.id.boton3);
    boton3.setOnTouchListener(new OnTouchListener() {
    });
    boton4= (Button)findViewById(R.id.boton4);
    boton4.setOnTouchListener(new OnTouchListener() {
    });
}

private void conectar(final String selector) {
      new Thread() {
          @Override
          public void run() {
                 try {
                     // code runs in a thread
                       runOnUiThread(new Runnable() {
                              @Override
                              public void run() {
                                  try {
                                    definir (selector);
                                  } catch (Exception e) {
                                    System.out.println("holi");
                                  }
                              }
                       });
                 } catch (final Exception ex) {
                }
          }
   }.start();
}
public void definir(String selector) throws Exception{
    valor = "http://192.168.240.1/arduino/" + selector;
    URL url = new URL(valor);
    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
    try {
        InputStream in = new BufferedInputStream(urlConnection.getInputStream());
        leer(in);
        }
    finally {
         urlConnection.disconnect();
        }
}

public void leer(InputStream in) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    if ((reader.readLine()) != "1") throw new IOException();
    //Arduino is programmed to print "1" when connection succedes
}

public void Alerta(){
    Context context = getApplicationContext();
    CharSequence text = "Conexion erronea";
    int duration = Toast.LENGTH_SHORT;
    Toast toast = Toast.makeText(context, text, duration);
    toast.show();
}