sharee.bike-App/Meinkonrad/TINK/View/Map/MapPage.xaml.cs

using System;
using System.Threading.Tasks;
#if USEFLYOUT
using TINK.View.MasterDetail;
#endif
using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace TINK.View.Map
{
    using Serilog;
    using TINK.ViewModel.Map;

    [XamlCompilation(XamlCompilationOptions.Compile)]
#if USEFLYOUT
    public partial class MapPage : ContentPage, IViewService, IDetailPage
#else
    public partial class MapPage : ContentPage, IViewService
#endif
    {
        /// <summary> View model to notify about whether page appears or hides. </summary>
        private MapPageViewModel MapPageViewModel { get; set; }

        /// <summary> Initialization status to ensure initialization logic is not called multiple times. </summary>
        private bool isInitializationStarted = false;

        /// <summary>
        /// Constructs map page instance.
        /// </summary>
        public MapPage()
        {
            InitializeComponent();
        }

        /// <summary>
        /// Displays alert message.
        /// </summary>
        /// <param name="title">Title of message.</param>
        /// <param name="message">Message to display.</param>
        /// <param name="cancel">Type of buttons.</param>
        public new async Task DisplayAlert(string title, string message, string cancel)
            => await App.Current.MainPage.DisplayAlert(title, message, cancel);

        /// <summary> Displays alert message.</summary>
        /// <param name="title">Title of message.</param>
        /// <param name="message">Message to display.</param>
        /// <param name="details">Detailed error description.</param>
        /// <param name="cancel">Type of buttons.</param>
        public async Task DisplayAdvancedAlert(
            string title,
            string message,
            string details,
            string cancel)
            => await App.Current.MainPage.DisplayAlert(title, $"{message}\r\nDetails:\r\n{details}", cancel);

        /// <summary> Displays detailed alert message.</summary>
        /// <param name="title">Title of message.</param>
        /// <param name="message">Message to display.</param>
        /// <param name="details">Detailed error description.</param>
        /// <param name="accept">Text of accept button.</param>
        /// <param name="cancel">Text of cancel button.</param>
        /// <returns>True if user pressed accept.</returns>
        public async Task<bool> DisplayAdvancedAlert(string title, string message, string details, string accept, string cancel)
            => await App.Current.MainPage.DisplayAlert(title, $"{message}\r\nDetails:\r\n{details}", accept, cancel);

        /// <summary>
        /// Displays alert message.
        /// </summary>
        /// <param name="title">Title of message.</param>
        /// <param name="message">Message to display.</param>
        /// <param name="accept">Text of accept button.</param>
        /// <param name="cancel">Text of button.</param>
        /// <returns>True if user pressed accept.</returns>
        public new async Task<bool> DisplayAlert(string title, string message, string accept, string cancel)
            => await App.Current.MainPage.DisplayAlert(title, message, accept, cancel);

#if USEFLYOUT
        /// <summary>
        /// Creates and a page an shows it.
        /// </summary>
        /// <param name="p_oTypeOfPage">Type of page to show.</param>
        public void ShowPage(ViewTypes type, string title = null)
            => NavigationMasterDetail.ShowPage(type.GetViewType(), title);
#else
        /// <summary> Shows a page.</summary>
        /// <param name="route">Route of the page to show.</param>
        public async Task ShowPage(string route) => await Shell.Current.GoToAsync(route);
#endif

        /// <summary> Pushes a page onto the modal stack. </summary>
        /// <param name="typeOfPage">Type of page to display.</param>
        public async Task PushModalAsync(ViewTypes typeOfPage)
            => await Navigation.PushModalAsync((Page)Activator.CreateInstance(typeOfPage.GetViewType()));

        /// <summary> Pops a page from the modal stack. </summary>
        public async Task PopModalAsync()
            => await Navigation.PopModalAsync();

        /// <summary> Pushes a page onto the stack. </summary>
        /// <param name="typeOfPage">Page to display.</param>
        public async Task PushAsync(ViewTypes typeOfPage)
        {
#if USEFLYOUT
            var page = Activator.CreateInstance(typeOfPage.GetViewType()) as IDetailPage;
#else
            var page = Activator.CreateInstance(p_oTypeOfPage.GetViewType());
#endif
            if (page == null)
            {
                return;
            }

#if USEFLYOUT
            page.NavigationMasterDetail = NavigationMasterDetail;
#endif

            await Navigation.PushAsync((Page)page);
        }

#if USCSHARP9
        public Task<IViewService.IUserFeedback> DisplayUserFeedbackPopup() => throw new NotSupportedException();
#else
        public Task<IUserFeedback> DisplayUserFeedbackPopup(string co2Saving = null) => throw new NotSupportedException();
#endif

#if USEFLYOUT
        /// <summary> Delegate to perform navigation.</summary>
        public INavigationMasterDetail NavigationMasterDetail { private get; set; }

#endif
        /// <summary>
        /// Invoked when page is shown. 
        /// Starts update process.
        /// </summary>
        protected async override void OnAppearing()
        {
            // Don't repeat the initialization if it has been completed already.
            if (isInitializationStarted) return;
            isInitializationStarted = true;

            // Pass reference to member Navigation to show bikes at station x dialog.
            try
            {
                Log.ForContext<MapPage>().Verbose("Constructing map page view model.");

#if TRYNOTBACKSTYLE
                MapPageViewModel = new MapPageViewModel();
#else
                MapPageViewModel = CreateMapPageViewModel();
#endif
            }
            catch (Exception exception)
            {
                Log.ForContext<MapPage>().Error("Constructing map page view model failed. {Exception}", exception);
                return;
            }

            try
            {
                BindingContext = MapPageViewModel;

#if USEFLYOUT
                MapPageViewModel.NavigationMasterDetail = NavigationMasterDetail;
#endif
            }
            catch (Exception exception)
            {
                Log.ForContext<MapPage>().Error("Setting binding/ navigaton on map page failed. {Exception}", exception);
                return;
            }

            try
            {
                ApplyCustomiOSStyling();
            }
            catch (Exception exception)
            {
                // Continue because styling is not essential.
                Log.ForContext<MapPage>().Error("IOS specific styling of map page failed. {Exception}", exception);
            }

            try
            {
                base.OnAppearing();
            }
            catch (Exception exception)
            {
                // Continue because styling is not essential.
                Log.ForContext<MapPage>().Error("Invoking OnAppearing of base failed. {Exception}", exception);
                return;
            }

            try
            {
                // Pre move and scanle maps to avoid initial display of map in Rome.
                PremoveAndScaleMap();
            }
            catch (Exception exception)
            {
                // Continue because a map not beeing moved/ scaled is no reason for aborting startup.
                Log.ForContext<MapPage>().Error("Moving and scaling map failed. {Exception}", exception);
            }

            try
            {
                Log.ForContext<MapPage>().Verbose("Invoking OnAppearing on map page view model.");
                await MapPageViewModel.OnAppearing();
            }
            catch (Exception exception)
            {
                Log.ForContext<MapPage>().Error("Invoking OnAppearing on map page view model failed. {Exception}", exception);
                return;
            }
        }

        /// <summary>
        /// Premoves the Map to a certain location.
        /// </summary>
        private void PremoveAndScaleMap()
        {
            Log.ForContext<MapPage>().Verbose("Moving and scaling map.");
            MapPageViewModel.MoveAndScale(
                (mapSpan) => MyMap.MoveToRegion(mapSpan),
                App.ModelRoot.ActiveMapSpan);
        }

        /// <summary>
        /// Creates the Map Page's view model.
        /// </summary>
        private MapPageViewModel CreateMapPageViewModel()
        {
            Log.ForContext<MapPage>().Verbose("Constructing map page view model.");
            return new MapPageViewModel(
                App.ModelRoot,
                App.PermissionsService,
                App.BluetoothService,
                App.GeolocationServicesContainer.Active,
                (mapspan) => MyMap.MoveToRegion(mapspan),
                this,
                Navigation);
        }

        /// <summary>
        /// Applies iOS specific styling to branded Buttons.
        /// </summary>
        private void ApplyCustomiOSStyling()
        {
            if (Device.RuntimePlatform == Device.iOS)
            {
                TINKButton.BackgroundColor = Color.LightGray;
                TINKButton.BorderColor = Color.Black;
                TINKButton.Margin = new Thickness(10, 10, 10, 10);
                KonradButton.BackgroundColor = Color.LightGray;
                KonradButton.BorderColor = Color.Black;
                KonradButton.Margin = new Thickness(10, 10, 10, 10);
            }
        }

        /// <summary>
        /// Invoked when pages is closed/ hidden. 
        /// Stops update process.
        /// </summary>
        protected override async void OnDisappearing()
        {
            if (MapPageViewModel != null)
            {
                // View model might be null.
                await MapPageViewModel?.OnDisappearing();
            }

            base.OnDisappearing();
        }
    }
}