integrate back button

Author: christiannagel

Xamarin/BooksAppX/BooksAppX/BooksAppX.UWP/BooksAppX.UWP.csproj

@@ -157,7 +157,7 @@
       <Version>2.0.0</Version>
     </PackageReference>
     <PackageReference Include="Xamarin.Forms" Version="2.5.0.122203" />
-    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.1" />
+    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.6" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\..\PatternsXamarinShared\BooksLib\BooksLib.csproj">

Xamarin/BooksAppX/BooksAppX/BooksAppX/App.xaml.cs

@@ -23,6 +23,7 @@ public App()
         protected override void OnStart()
         {
             // Handle when your app starts
+            AppServices.GetService<INavigationService>().UseNavigation = true; // always use navigation
         }
 
         protected override void OnSleep()

Xamarin/BooksAppX/BooksAppX/BooksAppX/Views/MainPage.xaml.cs

@@ -4,6 +4,8 @@
 using Microsoft.Extensions.DependencyInjection;
 using BooksAppX.Services;
 using BooksLib.Services;
+using Framework.Services;
+using System.Threading.Tasks;
 
 namespace BooksAppX.Views
 {
@@ -16,5 +18,16 @@ public MainPage ()
 
             (Application.Current as App).AppServices.GetService<XamarinInitializeNavigationService>().SetNavigation(navigationPage.Navigation, PageNames.BooksPage);
         }
+
+        protected override bool OnBackButtonPressed()
+        {
+            OnBackButtonAsync();
+            return true;
+        }
+
+        private async void OnBackButtonAsync()
+        {
+            await (Application.Current as App).AppServices.GetService<INavigationService>().GoBackAsync();
+        }
     }
 }