LoginPresenter

override fun onServerLoginClicked(userName: String, password: String) {
        when {
            userName.isEmpty() -> getView()?.showValidationMessage(AppConstants.EMPTY_USER_NAME_ERROR)
            password.isEmpty() -> getView()?.showValidationMessage(AppConstants.EMPTY_PASSWORD_ERROR)

            else -> {
                getView()?.showProgressBar()
                interactor?.let {
                    compositeDisposable.add(it.doServerLoginApiCall(userName, password)
                            .compose(schedulerProvider.ioToMainObservableScheduler())
                            .subscribe({ loginResponse ->
                                updateUserInSharedPref(loginResponse = loginResponse, loggedInMode = AppConstants.LoggedInMode.LOGGED_IN_MODE_SERVER)
                                getView()?.openMainActivity()
                            }, { err -> err.printStackTrace() }))
                }
            }
        }
    }