async Task Login() { IsBusy = true; PropChangedCallBack(); var authToken = await firebaseAuthenticator.LoginWithEmailPassword(Email.Value, Password.Value); if (string.IsNullOrEmpty(authToken) == false) { (Application.Current as App).AuthToken = authToken; await navigationService.PushAsync(new TourGuidePage()); } else { UserExists = false; } IsBusy = false; PropChangedCallBack(); }