sharee.bike-App/Meinkonrad/TINK/View/RootFlyout/RootPage.xaml.cs

using System;
using TINK.Model.Station;
#if USEFLYOUT
using TINK.View.MasterDetail;
#endif
using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace TINK.View.Root
{
	/// <summary>
	/// Mamages creation of detail pages if a flyout page menu entry is selected.
	/// Exposes flyout page style navigation which is used by detail pages.
	/// </summary>
	/// <remarks>
	/// Examples of use cases when detail pages do navigation:
	// - switch to map page after succesfully logging in/ logging out
	// - switch to login page form bikes at station page if not yet logged in
	/// </remarks>
	[XamlCompilation(XamlCompilationOptions.Compile)]
#if USEFLYOUT
    public partial class RootPage : FlyoutPage, INavigationMasterDetail
#else
	public partial class RootPage : FlyoutPage
#endif
	{
		public RootPage()
		{
			InitializeComponent();
			FlyoutPage.ListView.ItemSelected += OnListViewItemSelected;

			// Any type of split behaviour conflics with map shifting functionality (assuming FlyoutPage behaves same like MasterDetailPage).
			FlyoutLayoutBehavior = FlyoutLayoutBehavior.Popover;

			var navigationPage = Detail as NavigationPage;
			if (navigationPage == null)
			{
				return;
			}

#if USEFLYOUT
            var detailPage = navigationPage.RootPage as IDetailPage;
            if (detailPage == null)
            {
                return;
            }

            detailPage.NavigationMasterDetail = this;
#endif
		}

		/// <summary>
		/// Is called if a flyout page menu entry is selected.
		/// Creates  a new page.
		/// </summary>
		private void OnListViewItemSelected(object sender, SelectedItemChangedEventArgs e)
		{
			if (!(e.SelectedItem is RootPageFlyoutMenuItem item))
			{
				// Unexpected argument detected.
				return;
			}

			// Set selected station to new 
			App.ModelRoot.SelectedStation = new NullStation();

			ShowPage(item.TargetType, item.Title);

			IsPresented = false;
			FlyoutPage.ListView.SelectedItem = null;
		}

		/// <summary>
		/// Shows a detail page.
		/// </summary>
		/// <param name="typeOfPage">Type of page to show.</param>
		/// <param name="title">Title of page.</param>
		public void ShowPage(Type typeOfPage, string title)
		{
			var page = (Page)Activator.CreateInstance(typeOfPage);
			page.Title = title;

#if USEFLYOUT
            if (page is IDetailPage detailPage)
            {
                // Detail page needs reference to perform navigation.
                // Examples see above in xdoc of class.
                detailPage.NavigationMasterDetail = this;
            }
#endif

			Detail = new NavigationPage(page);
		}
	}
}