private void Button_TouchUpInside(object sender, EventArgs e)
        {
            UINavigationBar.Appearance.SetTitleTextAttributes(new UITextAttributes
            {
                TextColor = UIColor.Black
            });

            var mainPage = new MyMaterialPage().CreateViewController();

            //mainPage.Title = "Forms page";
            NavigationController.PushViewController(mainPage, true);
        }
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            SetContentView(Resource.Layout.FormsActivity);
            var fragment = this.FindViewById <FrameLayout>(Resource.Id.fragment_frame_layout);

            fragment.Visibility = Android.Views.ViewStates.Visible;
            var callHistoryPage = new MyMaterialPage().CreateSupportFragment(this);

            SupportFragmentManager
            .BeginTransaction()
            .AddToBackStack(null)
            .Replace(Resource.Id.fragment_frame_layout, callHistoryPage)
            .Commit();
        }