fix navigation

christiannagel · christiannagel · commit 37d5815100b7 · 2018-02-03T13:47:46.000+01:00
diff --git a/Patterns/BooksSample/BooksApp/App.xaml.cs b/Patterns/BooksSample/BooksApp/App.xaml.cs
@@ -1,9 +1,12 @@
-﻿using System;
+﻿using Framework.Services;
+using System;
 using Windows.ApplicationModel;
 using Windows.ApplicationModel.Activation;
+using Windows.UI.Core;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Navigation;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace BooksApp
 {
@@ -61,6 +64,13 @@ protected override void OnLaunched(LaunchActivatedEventArgs e)
                 // Ensure the current window is active
                 Window.Current.Activate();
             }
+
+            var navigationService = ApplicationServices.Instance.ServiceProvider.GetService<INavigationService>();
+            SystemNavigationManager.GetForCurrentView().BackRequested += (sender, e1) =>
+            {
+                e1.Handled = true;
+                navigationService.GoBackAsync();
+            };
         }
 
         /// <summary>
diff --git a/Patterns/BooksSample/BooksApp/MainPage.xaml.cs b/Patterns/BooksSample/BooksApp/MainPage.xaml.cs
@@ -20,7 +20,11 @@ public MainPage()
 
         private void OnSizeChanged(object sender, SizeChangedEventArgs e)
         {
-            EventAggregator<NavigationInfoEvent>.Instance.Publish(this, new NavigationInfoEvent { UseNavigation = e.NewSize.Width < 1024 });
+            ViewModel.UseNavigation(e.NewSize.Width < 1024);
+            FireNavigation(e.NewSize.Width);
         }
+
+        private void FireNavigation(double width) =>
+            EventAggregator<NavigationInfoEvent>.Instance.Publish(this, new NavigationInfoEvent { UseNavigation = width < 1024 });
     }
 }
diff --git a/Patterns/BooksSample/BooksApp/Services/UWPNavigationService.cs b/Patterns/BooksSample/BooksApp/Services/UWPNavigationService.cs
@@ -17,6 +17,8 @@ public UWPNavigationService(UWPInitializeNavigationService initializeNavigation)
             _initializeNavigation = initializeNavigation ?? throw new ArgumentNullException(nameof(initializeNavigation));
         }
 
+        public bool UseNavigation { get; set; }
+
         private Dictionary<string, Type> _pages;
         private Dictionary<string, Type> Pages => _pages ?? (_pages = _initializeNavigation.Pages);
 
diff --git a/Patterns/BooksSample/BooksApp/ViewModels/MainPageViewModel.cs b/Patterns/BooksSample/BooksApp/ViewModels/MainPageViewModel.cs
@@ -21,12 +21,17 @@ public class MainPageViewModel : ViewModelBase
         private readonly UWPInitializeNavigationService _initializeNavigationService;
         public MainPageViewModel(INavigationService navigationService, UWPInitializeNavigationService initializeNavigationService)
         {
-            _navigationService = navigationService;
-            _initializeNavigationService = initializeNavigationService;
+            _navigationService = navigationService ?? throw new ArgumentNullException(nameof(navigationService));
+            _initializeNavigationService = initializeNavigationService ?? throw new ArgumentNullException(nameof(initializeNavigationService));
         }
 
         public void SetNavigationFrame(Frame frame) => _initializeNavigationService.Initialize(frame, _pages);
 
+        public void UseNavigation(bool navigation)
+        {
+            _navigationService.UseNavigation = navigation;
+        }
+
         public void OnNavigationSelectionChanged(NavigationView sender, NavigationViewSelectionChangedEventArgs args)
         {
             if (args.SelectedItem is NavigationViewItem navigationItem)
diff --git a/Patterns/BooksSample/BooksApp/Views/BookDetailPage.xaml.cs b/Patterns/BooksSample/BooksApp/Views/BookDetailPage.xaml.cs
@@ -1,18 +1,22 @@
 ﻿using BooksLib.ViewModels;
 using Microsoft.Extensions.DependencyInjection;
-using Windows.UI.Xaml;
+using Windows.UI.Core;
 using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Navigation;
 
 namespace BooksApp.Views
 {
     public sealed partial class BookDetailPage : Page
     {
-        public BookDetailPage()
-        {
-            this.InitializeComponent();
-            ViewModel.UseNavigation = true; // if the Page is used, enable navigation
-        }
+        public BookDetailPage() => InitializeComponent();
 
         public BookDetailViewModel ViewModel { get; } = ApplicationServices.Instance.ServiceProvider.GetService<BookDetailViewModel>();
+
+        protected override void OnNavigatedTo(NavigationEventArgs e)
+        {
+            SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Visible;
+
+            base.OnNavigatedTo(e);
+        }
     }
 }
diff --git a/Patterns/BooksSample/BooksApp/Views/BooksPage.xaml.cs b/Patterns/BooksSample/BooksApp/Views/BooksPage.xaml.cs
@@ -1,6 +1,8 @@
 ﻿using BooksLib.ViewModels;
 using Microsoft.Extensions.DependencyInjection;
+using Windows.UI.Core;
 using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Navigation;
 
 namespace BooksApp.Views
 {
@@ -9,10 +11,16 @@ public sealed partial class BooksPage : Page
         public BooksPage()
         {
             InitializeComponent();
-            ViewModel.UseNavigation = false;
             BookDetailUC.ViewModel = ApplicationServices.Instance.ServiceProvider.GetService<BookDetailViewModel>();
         }
 
         public BooksViewModel ViewModel { get; } = ApplicationServices.Instance.ServiceProvider.GetService<BooksViewModel>();
+
+        protected override void OnNavigatedTo(NavigationEventArgs e)
+        {
+            SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Collapsed;
+
+            base.OnNavigatedTo(e);
+        }
     }
 }
diff --git a/PatternsXamarinShared/BooksLib/ViewModels/BookDetailViewModel.cs b/PatternsXamarinShared/BooksLib/ViewModels/BookDetailViewModel.cs
@@ -18,9 +18,9 @@ public class BookDetailViewModel : EditableItemViewModel<Book>
         public BookDetailViewModel(IItemsService<Book> itemsService, INavigationService navigationService, IMessageService messageService, ILogger<BookDetailViewModel> logger)
             : base(itemsService)
         {
-            _itemsService = itemsService;
-            _navigationService = navigationService;
-            _messageService = messageService;
+            _itemsService = itemsService ?? throw new ArgumentNullException(nameof(itemsService));
+            _navigationService = navigationService ?? throw new ArgumentNullException(nameof(navigationService));
+            _messageService = messageService ?? throw new ArgumentNullException(nameof(messageService));
             _logger = logger;
 
             itemsService.SelectedItemChanged += (sender, book) =>
@@ -29,8 +29,6 @@ public BookDetailViewModel(IItemsService<Book> itemsService, INavigationService
             };
         }
 
-        public bool UseNavigation { get; set; }
-
         public override Book CreateCopy(Book item) =>
             new Book
             {
@@ -49,7 +47,6 @@ public override async Task OnSaveAsync()
             try
             {
                 await _itemsService.AddOrUpdateAsync(EditItem);
-                throw new Exception("bah");
             }
             catch (Exception ex)
             {
@@ -60,11 +57,10 @@ public override async Task OnSaveAsync()
 
         public override async Task OnEndEditAsync()
         {
-            if (UseNavigation)
+            if (_navigationService.UseNavigation)
             {
                 await _navigationService.GoBackAsync();
             }
-        }
-        
+        }  
     }
 }
diff --git a/PatternsXamarinShared/BooksLib/ViewModels/BookItemViewModel.cs b/PatternsXamarinShared/BooksLib/ViewModels/BookItemViewModel.cs
@@ -2,6 +2,7 @@
 using Framework;
 using Framework.Services;
 using Framework.ViewModels;
+using System;
 
 namespace BooksLib.ViewModels
 {
@@ -13,7 +14,7 @@ public class BookItemViewModel : ItemViewModel<Book>
         public BookItemViewModel(Book book, IItemsService<Book> booksService)
         {
             Item = book;
-            _booksService = booksService;
+            _booksService = booksService ?? throw new ArgumentNullException(nameof(booksService));
             DeleteBookCommand = new RelayCommand(OnDeleteBook);
         }
 
diff --git a/PatternsXamarinShared/BooksLib/ViewModels/BooksViewModel.cs b/PatternsXamarinShared/BooksLib/ViewModels/BooksViewModel.cs
@@ -4,6 +4,7 @@
 using Framework.Services;
 using Framework.ViewModels;
 using System;
+using System.Diagnostics;
 
 namespace BooksLib.ViewModels
 {
@@ -18,22 +19,15 @@ public BooksViewModel(IItemsService<Book> booksService, INavigationService navig
             _booksService = booksService ?? throw new ArgumentNullException(nameof(booksService));
             _navigationService = navigationService ?? throw new ArgumentNullException(nameof(navigationService));
 
-            EventAggregator<NavigationInfoEvent>.Instance.Event += (sender, e) =>
-            {
-                UseNavigation = e.UseNavigation;
-            };
-
             PropertyChanged += async (sender, e) =>
             {
-                if (UseNavigation && e.PropertyName == nameof(SelectedItem) && _navigationService.CurrentPage == PageNames.BooksPage)
+                if (_navigationService.UseNavigation && e.PropertyName == nameof(SelectedItem) && _navigationService.CurrentPage == PageNames.BooksPage)
                 {
                     await _navigationService.NavigateToAsync(PageNames.BookDetailPage);
                 }
             };
         }
 
-        public bool UseNavigation { get; set; }
-
         public override void OnAdd()
         {
             var newBook = new Book();
diff --git a/PatternsXamarinShared/Framework/Services/INavigationService.cs b/PatternsXamarinShared/Framework/Services/INavigationService.cs
@@ -4,6 +4,7 @@ namespace Framework.Services
 {
     public interface INavigationService
     {
+        bool UseNavigation { get; set; }
         Task NavigateToAsync(string page);
         Task GoBackAsync();
         string CurrentPage { get; }

Original file line number	Diff line number	Diff line change
`@@ -20,7 +20,11 @@ public MainPage()`
`20`	`20`
`21`	`21`	`private void OnSizeChanged(object sender, SizeChangedEventArgs e)`
`22`	`22`	`{`
`23`		`- EventAggregator<NavigationInfoEvent>.Instance.Publish(this, new NavigationInfoEvent { UseNavigation = e.NewSize.Width < 1024 });`
	`23`	`+ ViewModel.UseNavigation(e.NewSize.Width < 1024);`
	`24`	`+ FireNavigation(e.NewSize.Width);`
`24`	`25`	`}`
	`26`	`+`
	`27`	`+ private void FireNavigation(double width) =>`
	`28`	`+ EventAggregator<NavigationInfoEvent>.Instance.Publish(this, new NavigationInfoEvent { UseNavigation = width < 1024 });`
`25`	`29`	`}`
`26`	`30`	`}`
Original file line number	Diff line number	Diff line change
`@@ -17,6 +17,8 @@ public UWPNavigationService(UWPInitializeNavigationService initializeNavigation)`
`17`	`17`	`_initializeNavigation = initializeNavigation ?? throw new ArgumentNullException(nameof(initializeNavigation));`
`18`	`18`	`}`
`19`	`19`
	`20`	`+ public bool UseNavigation { get; set; }`
	`21`	`+`
`20`	`22`	`private Dictionary<string, Type> _pages;`
`21`	`23`	`private Dictionary<string, Type> Pages => _pages ?? (_pages = _initializeNavigation.Pages);`
`22`	`24`
Original file line number	Diff line number	Diff line change
`@@ -21,12 +21,17 @@ public class MainPageViewModel : ViewModelBase`
`21`	`21`	`private readonly UWPInitializeNavigationService _initializeNavigationService;`
`22`	`22`	`public MainPageViewModel(INavigationService navigationService, UWPInitializeNavigationService initializeNavigationService)`
`23`	`23`	`{`
`24`		`- _navigationService = navigationService;`
`25`		`- _initializeNavigationService = initializeNavigationService;`
	`24`	`+ _navigationService = navigationService ?? throw new ArgumentNullException(nameof(navigationService));`
	`25`	`+ _initializeNavigationService = initializeNavigationService ?? throw new ArgumentNullException(nameof(initializeNavigationService));`
`26`	`26`	`}`
`27`	`27`
`28`	`28`	`public void SetNavigationFrame(Frame frame) => _initializeNavigationService.Initialize(frame, _pages);`
`29`	`29`
	`30`	`+ public void UseNavigation(bool navigation)`
	`31`	`+ {`
	`32`	`+ _navigationService.UseNavigation = navigation;`
	`33`	`+ }`
	`34`	`+`
`30`	`35`	`public void OnNavigationSelectionChanged(NavigationView sender, NavigationViewSelectionChangedEventArgs args)`
`31`	`36`	`{`
`32`	`37`	`if (args.SelectedItem is NavigationViewItem navigationItem)`
Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,8 @@`
`1`	`1`	`using BooksLib.ViewModels;`
`2`	`2`	`using Microsoft.Extensions.DependencyInjection;`
	`3`	`+using Windows.UI.Core;`
`3`	`4`	`using Windows.UI.Xaml.Controls;`
	`5`	`+using Windows.UI.Xaml.Navigation;`
`4`	`6`
`5`	`7`	`namespace BooksApp.Views`
`6`	`8`	`{`
`@@ -9,10 +11,16 @@ public sealed partial class BooksPage : Page`
`9`	`11`	`public BooksPage()`
`10`	`12`	`{`
`11`	`13`	`InitializeComponent();`
`12`		`- ViewModel.UseNavigation = false;`
`13`	`14`	`BookDetailUC.ViewModel = ApplicationServices.Instance.ServiceProvider.GetService<BookDetailViewModel>();`
`14`	`15`	`}`
`15`	`16`
`16`	`17`	`public BooksViewModel ViewModel { get; } = ApplicationServices.Instance.ServiceProvider.GetService<BooksViewModel>();`
	`18`	`+`
	`19`	`+ protected override void OnNavigatedTo(NavigationEventArgs e)`
	`20`	`+ {`
	`21`	`+ SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Collapsed;`
	`22`	`+`
	`23`	`+ base.OnNavigatedTo(e);`
	`24`	`+ }`
`17`	`25`	`}`
`18`	`26`	`}`
Original file line number	Diff line number	Diff line change
`@@ -18,9 +18,9 @@ public class BookDetailViewModel : EditableItemViewModel<Book>`
`18`	`18`	`public BookDetailViewModel(IItemsService<Book> itemsService, INavigationService navigationService, IMessageService messageService, ILogger<BookDetailViewModel> logger)`
`19`	`19`	`: base(itemsService)`
`20`	`20`	`{`
`21`		`- _itemsService = itemsService;`
`22`		`- _navigationService = navigationService;`
`23`		`- _messageService = messageService;`
	`21`	`+ _itemsService = itemsService ?? throw new ArgumentNullException(nameof(itemsService));`
	`22`	`+ _navigationService = navigationService ?? throw new ArgumentNullException(nameof(navigationService));`
	`23`	`+ _messageService = messageService ?? throw new ArgumentNullException(nameof(messageService));`
`24`	`24`	`_logger = logger;`
`25`	`25`
`26`	`26`	`itemsService.SelectedItemChanged += (sender, book) =>`
`@@ -29,8 +29,6 @@ public BookDetailViewModel(IItemsService<Book> itemsService, INavigationService`
`29`	`29`	`};`
`30`	`30`	`}`
`31`	`31`
`32`		`- public bool UseNavigation { get; set; }`
`33`		`-`
`34`	`32`	`public override Book CreateCopy(Book item) =>`
`35`	`33`	`new Book`
`36`	`34`	`{`
`@@ -49,7 +47,6 @@ public override async Task OnSaveAsync()`
`49`	`47`	`try`
`50`	`48`	`{`
`51`	`49`	`await _itemsService.AddOrUpdateAsync(EditItem);`
`52`		`- throw new Exception("bah");`
`53`	`50`	`}`
`54`	`51`	`catch (Exception ex)`
`55`	`52`	`{`
`@@ -60,11 +57,10 @@ public override async Task OnSaveAsync()`
`60`	`57`
`61`	`58`	`public override async Task OnEndEditAsync()`
`62`	`59`	`{`
`63`		`- if (UseNavigation)`
	`60`	`+ if (_navigationService.UseNavigation)`
`64`	`61`	`{`
`65`	`62`	`await _navigationService.GoBackAsync();`
`66`	`63`	`}`
`67`		`- }`
`68`		`-`
	`64`	`+ }`
`69`	`65`	`}`
`70`	`66`	`}`
Original file line number	Diff line number	Diff line change
`@@ -2,6 +2,7 @@`
`2`	`2`	`using Framework;`
`3`	`3`	`using Framework.Services;`
`4`	`4`	`using Framework.ViewModels;`
	`5`	`+using System;`
`5`	`6`
`6`	`7`	`namespace BooksLib.ViewModels`
`7`	`8`	`{`
`@@ -13,7 +14,7 @@ public class BookItemViewModel : ItemViewModel<Book>`
`13`	`14`	`public BookItemViewModel(Book book, IItemsService<Book> booksService)`
`14`	`15`	`{`
`15`	`16`	`Item = book;`
`16`		`- _booksService = booksService;`
	`17`	`+ _booksService = booksService ?? throw new ArgumentNullException(nameof(booksService));`
`17`	`18`	`DeleteBookCommand = new RelayCommand(OnDeleteBook);`
`18`	`19`	`}`
`19`	`20`
Original file line number	Diff line number	Diff line change
`@@ -4,6 +4,7 @@`
`4`	`4`	`using Framework.Services;`
`5`	`5`	`using Framework.ViewModels;`
`6`	`6`	`using System;`
	`7`	`+using System.Diagnostics;`
`7`	`8`
`8`	`9`	`namespace BooksLib.ViewModels`
`9`	`10`	`{`
`@@ -18,22 +19,15 @@ public BooksViewModel(IItemsService<Book> booksService, INavigationService navig`
`18`	`19`	`_booksService = booksService ?? throw new ArgumentNullException(nameof(booksService));`
`19`	`20`	`_navigationService = navigationService ?? throw new ArgumentNullException(nameof(navigationService));`
`20`	`21`
`21`		`- EventAggregator<NavigationInfoEvent>.Instance.Event += (sender, e) =>`
`22`		`- {`
`23`		`- UseNavigation = e.UseNavigation;`
`24`		`- };`
`25`		`-`
`26`	`22`	`PropertyChanged += async (sender, e) =>`
`27`	`23`	`{`
`28`		`- if (UseNavigation && e.PropertyName == nameof(SelectedItem) && _navigationService.CurrentPage == PageNames.BooksPage)`
	`24`	`+ if (_navigationService.UseNavigation && e.PropertyName == nameof(SelectedItem) && _navigationService.CurrentPage == PageNames.BooksPage)`
`29`	`25`	`{`
`30`	`26`	`await _navigationService.NavigateToAsync(PageNames.BookDetailPage);`
`31`	`27`	`}`
`32`	`28`	`};`
`33`	`29`	`}`
`34`	`30`
`35`		`- public bool UseNavigation { get; set; }`
`36`		`-`
`37`	`31`	`public override void OnAdd()`
`38`	`32`	`{`
`39`	`33`	`var newBook = new Book();`
Original file line number	Diff line number	Diff line change
`@@ -4,6 +4,7 @@ namespace Framework.Services`
`4`	`4`	`{`
`5`	`5`	`public interface INavigationService`
`6`	`6`	`{`
	`7`	`+ bool UseNavigation { get; set; }`
`7`	`8`	`Task NavigateToAsync(string page);`
`8`	`9`	`Task GoBackAsync();`
`9`	`10`	`string CurrentPage { get; }`