sharee.bike-App/LastenradBayern/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);
        }
    }
}