Merge pull request #32 from bricefriha/fix/issue#30

Avoid crashes if it's not connected to internet

AresNews/AresNews.Android/AresNews.Android.csproj

@@ -94,7 +94,7 @@
       <Version>0.1.6</Version>
     </PackageReference>
     <PackageReference Include="sqlite-net-pcl">
-      <Version>1.7.335</Version>
+      <Version>1.8.116</Version>
     </PackageReference>
     <PackageReference Include="SQLiteNetExtensions">
       <Version>2.1.0</Version>

AresNews/AresNews/App.xaml.cs

@@ -9,6 +9,7 @@
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using Xamarin.Essentials;
 using Xamarin.Forms;
 using Xamarin.Forms.Xaml;
 [assembly: ExportFont("FontAwesome5Free-Regular-400.otf", Alias = "FaRegular")]
@@ -24,6 +25,7 @@ public partial class App : Application
         public static Collection<Source> Sources { get; private set; }
         // Property SqlLite Connection
         public static SQLiteConnection SqLiteConn { get; set; }
+        public static SQLiteConnection BackUpConn { get; set; }
         public static Service WService { get; set; }
 
 
@@ -41,7 +43,7 @@ public App()
         {
 #if __LOCAL__
             // Set webservice
-            WService = new Service(host: "192.168.1.15",
+            WService = new Service(host: "192.168.1.12",
                                     port: 3000,
                                    sslCertificate: false);
 #else
@@ -62,11 +64,15 @@ public App()
 
             SqLiteConn.CreateTable<Source>();
             SqLiteConn.CreateTable<Article>();
+            BackUpConn.CreateTable<Source>();
+            BackUpConn.CreateTable<Article>();
 
             // Close the db
             //CloseDb();
 
             MainPage = new AppShell();
+
+
         }
         /// <summary>
         ///  Function to close the database 
@@ -85,14 +91,21 @@ public static void StartDb()
             string libraryPath = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
 
             var path = Path.Combine(libraryPath, "ares.db3");
+            var pathBackUp = Path.Combine(libraryPath, "aresBackup.db3");
 
             // Verify if a data base already exist
             if (!File.Exists(path))
                 // Create the folder path.
                 File.Create(path);
+
+            // Verify if a data base already exist
+            if (!File.Exists(pathBackUp))
+                // Create the folder path.
+                File.Create(pathBackUp);
 
             // Sqlite connection
             SqLiteConn = new SQLiteConnection(path);
+            BackUpConn = new SQLiteConnection(pathBackUp);
 
         }
 

AresNews/AresNews/AresNews.csproj

@@ -41,7 +41,7 @@
     <PackageReference Include="Custard" Version="0.1.6" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="Refractored.MvvmHelpers" Version="1.6.2" />
-    <PackageReference Include="sqlite-net-pcl" Version="1.7.335" />
+    <PackageReference Include="sqlite-net-pcl" Version="1.8.116" />
     <PackageReference Include="SQLiteNetExtensions" Version="2.1.0" />
     <PackageReference Include="System.ServiceModel.Syndication" Version="5.0.0" />
     <PackageReference Include="Xam.Plugin.HtmlLabel" Version="5.0.0" />

AresNews/AresNews/Models/BackupArticles.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace AresNews.Models
+{
+    public class BackupArticles : Article
+    {
+
+        public DateTime DateBackup { get; private set; } = DateTime.Now;
+
+    }
+}

AresNews/AresNews/ViewModels/BookmarkViewModel.cs

@@ -123,7 +123,10 @@ await Share.RequestAsync(new ShareTextRequest
                 });
             });
         }
-
+        /// <summary>
+        /// Get all the articles bookmarked from the local database
+        /// </summary>
+        /// <returns></returns>
         private static IEnumerable<Article> GetArticlesFromDb()
         {
             return App.SqLiteConn.GetAllWithChildren<Article>(recursive: true).Reverse<Article>();

AresNews/AresNews/ViewModels/NewsViewModel.cs

@@ -33,6 +33,7 @@ public ObservableCollection<Article> Articles
                 OnPropertyChanged();
             }
         }
+        private NewsPage CurrentPage { get; set; }
         // Command to add a Bookmark
         private readonly Command _addBookmark;
 
@@ -188,7 +189,24 @@ await Share.RequestAsync(new ShareTextRequest
         /// </summary>
         public async void FetchArticles()
         {
-            var articles = new ObservableCollection<Article>((IEnumerable<Article>)await App.WService.Get<IEnumerable<Article>>("feeds"));
+            var articles = new ObservableCollection<Article>();
+
+            try
+            {
+                articles = await App.WService.Get<ObservableCollection<Article>>("feeds");
+
+                // TODO: Empty the table before doing this
+                App.BackUpConn.DeleteAll<Article>();
+                App.BackUpConn.InsertAllWithChildren(articles);
+
+            }
+            catch (Exception ex)
+            {
+                articles = new ObservableCollection<Article> (GetBackupFromDb()) ;
+
+                var page = (NewsPage)((IShellSectionController)Shell.Current?.CurrentItem?.CurrentItem).PresentedPage;
+                page.DisplayOfflineMessage();
+            }
 
 
             // Update list of articles
@@ -210,6 +228,10 @@ public async void RefreshArticles ()
             }
 
         }
+        private static IEnumerable<Article> GetBackupFromDb()
+        {
+            return App.BackUpConn.GetAllWithChildren<Article>(recursive: true).Reverse<Article>();
+        }
         void ObservableCollectionCallback(IEnumerable collection, object context, Action accessMethod, bool writeAccess)
         {
             // `lock` ensures that only one thread access the collection at a time

AresNews/AresNews/Views/NewsPage.xaml.cs

@@ -11,8 +11,9 @@
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
-
+using Xamarin.Essentials;
 using Xamarin.Forms;
+using Xamarin.CommunityToolkit.Extensions;
 using Xamarin.Forms.Xaml;
 
 namespace AresNews.Views
@@ -40,6 +41,16 @@ public NewsPage()
         protected override void OnAppearing()
         {
             base.OnAppearing();
+
+            // Is the app connected to the internet
+            //if (Connectivity.NetworkAccess != NetworkAccess.Internet)
+            //{
+            //    this.DisplayToastAsync("You're offline", 60000);
+            //}
+        }
+        public void DisplayOfflineMessage ()
+        {
+            this.DisplayToastAsync("You're offline", 60000);
         }
     }
 }