public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            // Perform any additional setup after loading the view, typically from a nib.

            PasswordField.AutocorrectionType = UITextAutocorrectionType.No;
            PasswordField.KeyboardType       = UIKeyboardType.Default;
            PasswordField.ReturnKeyType      = UIReturnKeyType.Done;
            PasswordField.ClearButtonMode    = UITextFieldViewMode.WhileEditing;

            PasswordField.ShouldReturn = delegate
            {
                PasswordField.ResignFirstResponder();
                return(true);
            };

            SelectGroupLabel.Hidden = true;
            PasswordLabel.Hidden    = true;
            PasswordField.Hidden    = true;
            SubmitButton.Hidden     = true;
            GroupPicker.Hidden      = true;
            GoBackButton.Hidden     = true;


            FadeAnimation(SelectGroupLabel, isIn: false, duration: 1, onFinished: null);
            FadeAnimation(PasswordLabel, isIn: false, duration: 1, onFinished: null);
            FadeAnimation(PasswordField, isIn: false, duration: 1, onFinished: null);
            FadeAnimation(SubmitButton, isIn: false, duration: 1, onFinished: null);
            FadeAnimation(GroupPicker, isIn: false, duration: 1, onFinished: null);
            FadeAnimation(GoBackButton, isIn: false, duration: 1, onFinished: null);
        }
        public override void ViewDidLoad()
        {
            _didShowNotificationObserver = NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.DidShowNotification, KeyBoardDidShow, this);

            _willHideNotificationObserver = NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.WillHideNotification, KeyBoardWillHide, this);

            ActivityIndicator.StopAnimating();

            this.LoginField.ShouldReturn       += (textField) => textField.ResignFirstResponder();
            this.PasswordField.ShouldReturn    += (textField) => textField.ResignFirstResponder();
            this.AdressField.ShouldReturn      += (textField) => textField.ResignFirstResponder();
            this.PhoneNumberField.ShouldReturn += (textField) => textField.ResignFirstResponder();

            this.View.AddGestureRecognizer(new UITapGestureRecognizer(() =>
            {
                LoginField.ResignFirstResponder();
                PasswordField.ResignFirstResponder();
                AdressField.ResignFirstResponder();
                PhoneNumberField.ResignFirstResponder();
            }));

            RegistrationButton.TouchUpInside += async(sender, e) =>
            {
                Customers registrationFieldsForAsync = new Customers()
                {
                    Name = LoginField.Text, Password = PasswordField.Text, Adress = AdressField.Text, PhoneNumber = PhoneNumberField.Text
                };
                ActivityIndicator.StartAnimating();
                try
                {
                    RegistrationButton.Enabled = false;
                    LoginAndPasswordCheck.LoginCheck(registrationFieldsForAsync.Name);
                    LoginAndPasswordCheck.PasswordCheck(registrationFieldsForAsync.Password);
                    LoginAndPasswordCheck.AdressCheck(registrationFieldsForAsync.Adress);
                    LoginAndPasswordCheck.PhoneCheck(registrationFieldsForAsync.PhoneNumber);
                    await UsersCheckClass.TryToRegister(registrationFieldsForAsync);

                    AppDelegate.UserName = registrationFieldsForAsync.Name;
                    PerformSegue("RegistrationSegue", null);
                }
                catch (FiledsCheckException e1)
                {
                    ActivityIndicator.StopAnimating();
                    RegistrationButton.Enabled = true;
                    PresentViewController(GetAlertsClass.GetAlert(e1.Message), true, null);
                }
                catch (UserCheckClassException e1)
                {
                    ActivityIndicator.StopAnimating();
                    RegistrationButton.Enabled = true;
                    PresentViewController(GetAlertsClass.GetAlert(e1.Message), true, null);
                }
                catch
                {
                    ActivityIndicator.StopAnimating();
                    RegistrationButton.Enabled = true;
                    PresentViewController(GetAlertsClass.GetAlert("Не удалось подключиться к серверу"), true, null);
                }
            };
        }
        public override void TouchesEnded(NSSet touches, UIEvent evt)
        {
            base.TouchesEnded(touches, evt);

            // if they tap somewhere outside of the text fields,
            // hide the keyboard
            UserNameField.ResignFirstResponder( );
            PasswordField.ResignFirstResponder( );
        }