improving code styles which should increase performances

MainPage.xaml

@@ -4,13 +4,25 @@
              xmlns:hackerNews="clr-namespace:HackerNews"
              x:Class="HackerNews.MainPage"
              x:DataType="hackerNews:NewsViewModel">
-   <ListView x:Name="NewsListView" ItemSelected="NewsListView_OnItemSelected">
-       <ListView.ItemTemplate>
-           <DataTemplate>
-               <TextCell x:DataType="hackerNews:StoryModel"
-                   Text="{Binding Title}"
-                   Detail="{Binding CreatedAt}" />
+
+   <CollectionView x:Name="NewsCollectionView" 
+                   ItemsSource="{Binding TopStoryCollection}" 
+                   SelectionMode="Single" 
+                   SelectionChanged="NewsCollectionView_OnSelectionChanged">
+       <CollectionView.ItemTemplate>
+           <DataTemplate x:DataType="hackerNews:StoryModel">
+               <Frame Padding="10" Margin="5" BorderColor="LightGray">
+                   <StackLayout>
+                       <Label Text="{Binding Title}" 
+                              FontSize="18" 
+                              FontAttributes="Bold" />
+                       <Label Text="{Binding CreatedAt, StringFormat='{0:MMM dd, yyyy h:mm tt}'}" 
+                              FontSize="14" 
+                              TextColor="Gray" />
+                   </StackLayout>
+               </Frame>
            </DataTemplate>
-       </ListView.ItemTemplate>
-   </ListView>
+       </CollectionView.ItemTemplate>
+   </CollectionView>
+
 </ContentPage>

MainPage.xaml.cs

@@ -1,53 +1,42 @@
-using Microsoft.Extensions.Logging;
+namespace HackerNews;
 
-namespace HackerNews;
-
-public partial class MainPage
+public partial class MainPage : ContentPage
 {
     private readonly NewsViewModel _newsViewModel;
-
-    public MainPage()
+
+    // Constructor accepting NewsViewModel via Dependency Injection
+    public MainPage(NewsViewModel newsViewModel)
     {
         InitializeComponent();
+        _newsViewModel = newsViewModel;
 
-        // Set up the logger
-        var loggerFactory = LoggerFactory.Create(builder =>
-        {
-            builder.AddConsole(); // Add other logging providers as necessary
-        });
-
-        var logger = loggerFactory.CreateLogger<NewsViewModel>();
-
-        // Create an instance of NewsService, passing the loggerFactory if needed
-        var newsService = new NewsService(loggerFactory);
-
-        // Create the NewsViewModel instance
-        _newsViewModel = new NewsViewModel(newsService, logger);
-
-        // Set the ItemsSource for the NewsListView
-        NewsListView.ItemsSource = _newsViewModel.TopStoryCollection;
+        // Set the BindingContext for data binding in XAML
+        BindingContext = _newsViewModel;
     }
 
     protected override async void OnAppearing()
     {
         base.OnAppearing();
-        await _newsViewModel.Refresh();
+        await _newsViewModel.RefreshAsync();
     }
 
-    private async void NewsListView_OnItemSelected(object sender, SelectedItemChangedEventArgs e)
+    private async void NewsCollectionView_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
     {
-        var listView = (ListView)sender;
-        listView.SelectedItem = null;
-
-        if (e.SelectedItem is not StoryModel storyModel) return;
-        if (!string.IsNullOrEmpty(storyModel.Url))
-        {
-            var browserOptions = new BrowserLaunchOptions();
-            await Browser.Default.OpenAsync(storyModel.Url, browserOptions);
-        }
-        else
+        // Check if there is a selected item and access it directly by index
+        if (e.CurrentSelection.Count > 0 && e.CurrentSelection[0] is StoryModel storyModel)
         {
-            await DisplayAlert("Invalid Article", "ASK HN articles have no url", "OK");
+            // Clear selection
+            ((CollectionView)sender).SelectedItem = null;
+
+            if (!string.IsNullOrEmpty(storyModel.Url))
+            {
+                var browserOptions = new BrowserLaunchOptions { LaunchMode = BrowserLaunchMode.SystemPreferred };
+                await Browser.Default.OpenAsync(storyModel.Url, browserOptions);
+            }
+            else
+            {
+                await DisplayAlert("Invalid Article", "ASK HN articles have no URL", "OK");
+            }
         }
     }
-}
+}

NewsService.cs

@@ -11,22 +11,22 @@ public class NewsService(ILoggerFactory loggerFactory)
 
     private readonly ILogger<NewsService> _logger = loggerFactory.CreateLogger<NewsService>();
 
-    public async Task<string> GetTopStoryAsJson()
+    public async Task<string> GetTopStoryAsJsonAsync()
     {
         try
-        {
+         {
             return await _firebaseClient
                 .Child("topstories.json?print=pretty")
                 .OnceAsJsonAsync();
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "Error fetching top stories from Firebase");
-            throw;
+            _logger.LogError(ex, "Error fetching top stories from Firebase.");
+             throw;
         }
     }
 
-    public async Task<StoryModel> GetTopStory(string topStoryId)
+    public async Task<StoryModel> GetTopStoryAsync(string topStoryId)
     {
         try
         {

NewsViewModel.cs

@@ -7,12 +7,12 @@ namespace HackerNews;
 
 public class NewsViewModel(NewsService newsService, ILogger<NewsViewModel> logger) : ObservableObject
 {
-    public ObservableCollection<StoryModel> TopStoryCollection { get; } = new ObservableCollection<StoryModel>();
+    public ObservableCollection<StoryModel> TopStoryCollection { get; } = [];
 
     private readonly NewsService _newsService = newsService;
     private readonly ILogger<NewsViewModel> _logger = logger;
 
-    public async Task Refresh()
+    public async Task RefreshAsync()
     {
         // Ensure this method is called on the UI thread
         await MainThread.InvokeOnMainThreadAsync(async () =>
@@ -21,7 +21,7 @@ await MainThread.InvokeOnMainThreadAsync(async () =>
             {
                 TopStoryCollection.Clear();
 
-                await foreach (var story in GetTopStories().ConfigureAwait(false))
+                await foreach (var story in GetTopStoriesAsync())
                 {
                     InsertIntoSortedCollection(TopStoryCollection, (a, b) => b.Score.CompareTo(a.Score), story);
                 }
@@ -57,31 +57,39 @@ static void InsertIntoSortedCollection<T>(ObservableCollection<T> collection, Co
         }
     }
 
-    async IAsyncEnumerable<StoryModel> GetTopStories()
+    private async IAsyncEnumerable<StoryModel> GetTopStoriesAsync()
     {
-        var stories = new List<StoryModel>();
-
+        List<string> topStoryIds = [];
+        
         try
         {
-            var topStories = await _newsService.GetTopStoryAsJson();
-            var topStoryJson = JsonConvert.DeserializeObject<List<string>>(topStories);
-
-            foreach (var topStoryId in topStoryJson)
-            {
-                var story = await _newsService.GetTopStory(topStoryId);
-                stories.Add(story);  // Add to the temporary list
-            }
+            var topStoriesJson = await _newsService.GetTopStoryAsJsonAsync();
+            topStoryIds = JsonConvert.DeserializeObject<List<string>>(topStoriesJson);
         }
         catch (Exception ex)
         {
             _logger.LogError(ex, "Error while fetching top stories.");
-            throw;
+            yield break; // Stop if there’s an issue fetching the top story IDs
         }
-
-        // Yield the results after the try-catch block
-        foreach (var story in stories)
+
+        foreach (var id in topStoryIds)
         {
-            yield return story;
+            StoryModel story = null;
+
+            try
+            {
+                story = await _newsService.GetTopStoryAsync(id);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error fetching story with ID: {StoryId}", id);
+                continue; // Skip this story if there's an error fetching it
+            }
+
+            if (story != null)
+            {
+                yield return story; // Yield only if successfully fetched
+            }
         }
     }
 }

StoryModel.cs

@@ -2,11 +2,5 @@ namespace HackerNews;
 
 public record StoryModel(long Id, string By, long Score, long Time, string Title, string Url)
 {
-    public DateTime CreatedAt => UnixTimeStampToDateTimeOffset(Time).LocalDateTime;
-
-    static DateTimeOffset UnixTimeStampToDateTimeOffset(long unixTimeStamp)
-    {
-        var dateTimeOffset = new DateTimeOffset(1970, 1, 1, 0, 0, 0, 0, default);
-        return dateTimeOffset.AddSeconds(unixTimeStamp);
-    }
+    public DateTime CreatedAt => DateTimeOffset.FromUnixTimeSeconds(Time).LocalDateTime;
 }