add sub view if it doesn't exist - ios

Question

on item click I add sub view (UIButton) to my supper view and want to remove it old one when user click again or just change title it isn't first click.
this is my custom renderer:
var text = new UIButton ();
protected override void OnElementChanged (ElementChangedEventArgs<Image> e)
{
base.OnElementChanged (e);
if (Control == null)
return;
if (this.Element != null) {
Original = (SpecLogoImage)this.Element;
}
TargetView = Control as UIImageView;
text.Layer.CornerRadius = 5;
text.Font = UIFont.FromName ("DIN Condensed", text.Font.PointSize);
text.TouchUpInside += delegate {
text.RemoveFromSuperview ();
};
var rec = new UILongPressGestureRecognizer (() => {
text.SetTitle(Original._hint, UIControlState.Normal);
text.TitleLabel.LineBreakMode = UILineBreakMode.WordWrap;
text.SizeToFit ();
text.Frame = new CGRect ((UIApplication.SharedApplication.KeyWindow.Frame.Width / 2.0f) - (250 / 2.0f),
this.Superview.Superview.Superview.Frame.Height / 2.0f, 250, text.Frame.Height);
if (text.Superview==null) {
Animate (0.6f, () => {
this.Superview.Superview.Superview.AddSubview (text);
}, () => {
text.Layer.ZPosition = int.MaxValue;
});
}
});
text.SetTitleColor (UIColor.White, UIControlState.Normal);
text.BackgroundColor = UIColor.Black;
TargetView.UserInteractionEnabled = true;
TargetView.AddGestureRecognizer (rec);
}
}
every time user click Superview is null, what is the problem ?