public void enablePresenceClickEventHandler(View v) {
    EditText editTextServer = (EditText) findViewById(R.id.EditTextServer);
    EditText editTextApplicationKey = (EditText) findViewById(R.id.EditTextApplicationKey);
    EditText editTextChannel = (EditText) findViewById(R.id.EditTextChannel);
    CheckBox checkBoxIsCluster = (CheckBox) findViewById(R.id.CheckBoxIsCluster);

    Ortc.enablePresence(
        editTextServer.getText().toString(),
        checkBoxIsCluster.isChecked(),
        editTextApplicationKey.getText().toString(),
        defaultPrivateKey,
        editTextChannel.getText().toString(),
        true,
        new OnEnablePresence() {
          @Override
          public void run(Exception error, String result) {
            final Exception exception = error;
            final String resultText = result;
            runOnUiThread(
                new Runnable() {
                  @Override
                  public void run() {
                    if (exception != null) {
                      log(String.format("Error: %s", exception.getMessage()));
                    } else {
                      log(resultText);
                    }
                  }
                });
          }
        });
  }