Move textfield when keyboard appers

Hello! I'm really new to Xamarin and I've come to an issue that is out of my league. I've read and copied this code to my project http://forums.xamarin.com/discussion/comment/23235/#Comment_23235 But I'm not seeing any changes!, I addeda UIScrollView on the interface builder but now I'm unable to click on any of my textfields. This is my code

`public partial class LoginScreen : UIViewController { WaitingScreen waitingScreen; public LoginScreen () : base ("LoginScreen", null) { }

    public override void DidReceiveMemoryWarning ()
    {
        // Releases the view if it doesn't have a superview.
        base.DidReceiveMemoryWarning ();

        // Release any cached data, images, etc that aren't in use.
    }

    public override void ViewDidLoad ()
    {
        this.RegistrarButton.TouchUpInside += (sender, e) => {
        if(waitingScreen==null)
            {
                waitingScreen=new WaitingScreen();
                this.NavigationController.PushViewController(waitingScreen,true);
            }

        };
        var g = new UITapGestureRecognizer(() => View.EndEditing(true));
        View.AddGestureRecognizer(g);
        base.ViewDidLoad ();
        if (HandlesKeyboardNotifications()) {
            RegisterForKeyboardNotifications();
        }

        // Perform any additional setup after loading the view, typically from a nib.
    }



    #region Keyboard adjust

    /// <summary>
    /// Set this field to any view inside the scroll view to center this view instead of the current responder
    /// </summary>
    protected UIView ViewToCenterOnKeyboardShown;
    public virtual bool HandlesKeyboardNotifications()
    {
        return false;
    }

    protected virtual void RegisterForKeyboardNotifications()
    {
        NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.WillHideNotification, OnKeyboardNotification);
        NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.WillShowNotification, OnKeyboardNotification);
    }

    /// <summary>
    /// Gets the UIView that represents the "active" user input control (e.g. textfield, or button under a text field)
    /// </summary>
    /// <returns>
    /// A <see cref="UIView"/>
    /// </returns>
    protected virtual UIView KeyboardGetActiveView()
    {
        return View.FindFirstResponder();
    }

    private void OnKeyboardNotification (NSNotification notification)
    {
        if (!IsViewLoaded) return;

        //Check if the keyboard is becoming visible
        var visible = notification.Name == UIKeyboard.WillShowNotification;

        //Start an animation, using values from the keyboard
        UIView.BeginAnimations ("AnimateForKeyboard");
        UIView.SetAnimationBeginsFromCurrentState (true);
        UIView.SetAnimationDuration (UIKeyboard.AnimationDurationFromNotification (notification));
        UIView.SetAnimationCurve ((UIViewAnimationCurve)UIKeyboard.AnimationCurveFromNotification (notification));

        //Pass the notification, calculating keyboard height, etc.
        bool landscape = InterfaceOrientation == UIInterfaceOrientation.LandscapeLeft || InterfaceOrientation == UIInterfaceOrientation.LandscapeRight;
        var keyboardFrame = visible
            ? UIKeyboard.FrameEndFromNotification(notification)
                : UIKeyboard.FrameBeginFromNotification(notification);

        OnKeyboardChanged (visible, landscape ? keyboardFrame.Width : keyboardFrame.Height);

        //Commit the animation
        UIView.CommitAnimations ();
    }

    /// <summary>
    /// Override this method to apply custom logic when the keyboard is shown/hidden
    /// </summary>
    /// <param name='visible'>
    /// If the keyboard is visible
    /// </param>
    /// <param name='keyboardHeight'>
    /// Calculated height of the keyboard (width not generally needed here)
    /// </param>
    protected virtual void OnKeyboardChanged (bool visible, float keyboardHeight)
    {
        var activeView = ViewToCenterOnKeyboardShown ?? KeyboardGetActiveView();
        if (activeView == null)
            return;

        var scrollView = activeView.FindSuperviewOfType(View, typeof(UIScrollView)) as UIScrollView;
        if (scrollView == null)
            return;

        if (!visible)
            RestoreScrollPosition(scrollView);
        else
            CenterViewInScroll(activeView, scrollView, keyboardHeight);
    }

    protected virtual void CenterViewInScroll(UIView viewToCenter, UIScrollView scrollView, float keyboardHeight)
    {
        var contentInsets = new UIEdgeInsets(0.0f, 0.0f, keyboardHeight, 0.0f);
        scrollView.ContentInset = contentInsets;
        scrollView.ScrollIndicatorInsets = contentInsets;

        // Position of the active field relative isnside the scroll view
        RectangleF relativeFrame = viewToCenter.Superview.ConvertRectToView(viewToCenter.Frame, scrollView);

        bool landscape = InterfaceOrientation == UIInterfaceOrientation.LandscapeLeft || InterfaceOrientation == UIInterfaceOrientation.LandscapeRight;
        var spaceAboveKeyboard = (landscape ? scrollView.Frame.Width : scrollView.Frame.Height) - keyboardHeight;

        // Move the active field to the center of the available space
        var offset = relativeFrame.Y - (spaceAboveKeyboard - viewToCenter.Frame.Height) / 2;
        scrollView.ContentOffset = new PointF(0, offset);
    }

    protected virtual void RestoreScrollPosition(UIScrollView scrollView)
    {
        scrollView.ContentInset = UIEdgeInsets.Zero;
        scrollView.ScrollIndicatorInsets = UIEdgeInsets.Zero;
    }

    /// <summary>
    /// Call it to force dismiss keyboard when background is tapped
    /// </summary>
    protected void DismissKeyboardOnBackgroundTap()
    {
        // Add gesture recognizer to hide keyboard
        var tap = new UITapGestureRecognizer { CancelsTouchesInView = false };
        tap.AddTarget(() => View.EndEditing(true));
        View.AddGestureRecognizer(tap);
    }

    #endregion


}
public static class ViewExtensions
{
    /// <summary>
    /// Find the first responder in the <paramref name="view"/>'s subview hierarchy
    /// </summary>
    /// <param name="view">
    /// A <see cref="UIView"/>
    /// </param>
    /// <returns>
    /// A <see cref="UIView"/> that is the first responder or null if there is no first responder
    /// </returns>
    public static UIView FindFirstResponder(this UIView view)
    {
        if (view.IsFirstResponder)
        {
            return view;
        }
        foreach (UIView subView in view.Subviews)
        {
            var firstResponder = subView.FindFirstResponder();
            if (firstResponder != null)
                return firstResponder;
        }
        return null;
    }

    /// <summary>
    /// Find the first Superview of the specified type (or descendant of)
    /// </summary>
    /// <param name="view">
    /// A <see cref="UIView"/>
    /// </param>
    /// <param name="stopAt">
    /// A <see cref="UIView"/> that indicates where to stop looking up the superview hierarchy
    /// </param>
    /// <param name="type">
    /// A <see cref="Type"/> to look for, this should be a UIView or descendant type
    /// </param>
    /// <returns>
    /// A <see cref="UIView"/> if it is found, otherwise null
    /// </returns>
    public static UIView FindSuperviewOfType(this UIView view, UIView stopAt, Type type)
    {
        if (view.Superview != null)
        {
            if (type.IsAssignableFrom(view.Superview.GetType()))
            {
                return view.Superview;
            }

            if (view.Superview != stopAt)
                return view.Superview.FindSuperviewOfType(stopAt, type);
        }

        return null;
    }
}

} `

What I'm missing? EDIT: this is the photo of my xib http://postimg.org/image/ocyozzyl7/