@Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SharedPreferences prefs = getPreferences(MODE_PRIVATE);
    String udnPref = prefs.getString("UDN", null);
    if (udnPref != null) {
      // we have a stored UDN, so use it
      udn = new UDN(udnPref);
      Log.i("udn", "old udn: " + udn.toString());
    } else {
      // we need to generate a udn and store it
      udn = new UDN(UUID.randomUUID());
      Log.i("udn", "new udn: " + udn.toString());
      SharedPreferences.Editor editor = prefs.edit();
      editor.putString("UDN", udn.getIdentifierString());
      editor.commit();
    }

    mDataStoreInterfaceImpl = new DataStoreInterfaceImpl(getContentResolver());

    setContentView(R.layout.activity_main);

    final ImageView fridgeImg = (ImageView) findViewById(R.id.imageView1);
    fridgeImg.setOnClickListener(
        new View.OnClickListener() {
          private boolean fridgeState;

          public void onClick(View v) {
            if (fridgeState) {
              fridgeImg.setImageResource(R.drawable.fridge_closed);
              fridgeState = false;
              mDoorOpenAlarm.resetAlarm();
            } else {
              fridgeImg.setImageResource(R.drawable.fridge_off);
              fridgeState = true;
              mDoorOpenAlarm.setAlarm();
            }
          }
        });

    mSensorChangedLed = (Led) findViewById(R.id.redled);
    mSensorReadLed = (Led) findViewById(R.id.greenled);

    setupSensorNetwork();
    // setText();

  }
  public void showAboutDialog() {

    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);

    // set title
    alertDialogBuilder.setTitle(APP_ABOUT_TITLE);

    // set dialog message
    String message = APP_ABOUT_MESSAGE + "\n" + udn.toString();
    alertDialogBuilder
        .setMessage(message)
        .setCancelable(false)
        .setPositiveButton(
            R.string.ok,
            new DialogInterface.OnClickListener() {
              public void onClick(DialogInterface dialog, int id) {}
            });

    // create alert dialog
    AlertDialog alertDialog = alertDialogBuilder.create();
    alertDialog.show();
  }
 public static Device getDevice(String uuid) {
   return uuid != null && upnpService != null
       ? upnpService.getRegistry().getDevice(UDN.valueOf(uuid), false)
       : null;
 }