protected async override void OnAppearing() { firebaseService = new FirebaseService(); var announcementList = await firebaseService.GetAnnouncements(); announcements = new ObservableCollection <Announcement>(announcementList); AnnouncementsView.ItemsSource = announcements; if (announcements.Count == 0) { EmptyLabel.Text = "Henüz eklenmiş bir duyuru mevcut değil"; EmptyLabel.IsVisible = true; AnnouncementsView.IsVisible = false; } base.OnAppearing(); }