private async void Menu_ItemTapped(object sender, ItemTappedEventArgs e)
        {
            if (e.Item.ToString() == "Nazad")
            {
                await Navigation.PopAsync();
            }


            Page gotoPage = new GenericPage(e.Item.ToString());

            switch (e.Item.ToString())
            {
            case "Projekti":
                //gotoPage = new DetailsPage();
                break;

            case "Aktivnosti":
                //gotoPage = new MainPage();
                break;

            case "Zahtevi":
                //gotoPage = new DokumentaPage();
                break;

            default:
                //gotoPage = new MainPage();
                break;
            }
            Detail = new NavigationPage(gotoPage);
            ((ListView)sender).SelectedItem = null;
            this.IsPresented = false;
        }
        private async void OnClick(object sender, EventArgs e)
        {
            Page gotoPage = null;

            switch ((sender as ToolbarItem).Text)
            {
            case "Podesavanja":
                gotoPage = new PodesavanjaPage();
                break;

            case "Nalog":
                gotoPage = new GenericPage("Nalog Page");
                break;

            case "Odjavi se":     // ova se malo razlikuje
                App.Current.MainPage = new LoginPage();
                return;
            }
            await Navigation.PushAsync(gotoPage);
        }