public override void ViewDidAppear(bool animated)
{
base.ViewDidAppear(animated);
var font = UIFont.FromName("Avenir-Medium", 18f);
var list = new List<UIViewController> { vc1, vc2 };
var tabbar = new MikeCodesDotNET.iOS.Controls.ScrollingTabView(list, font);
tabbar.Frame = placeholderView.Bounds;
placeholderView.AddSubview(tabbar);
}