BtLogIn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {

                    username = etUsername.getText().toString();
                    password = etPassword.getText().toString();
                    baseUrl = etServerUrl.getText().toString();

                    ApiAuthenticationClient apiAuthenticationClient =
                            new ApiAuthenticationClient(
                                    baseUrl
                                    , username
                                    , password
                            );

                    AsyncTask<Void, Void, String> execute = new ExecuteNetworkOperation(apiAuthenticationClient);
                    execute.execute();
                } catch (Exception ex) {
                }
            }
        });