The app crash when I am trying to populate the carrouselView a second time. When the app start I get data to display on carrouselView, it work the first time on IOS and Android:
Here is the xalm :
<CarouselView x:Name="newsCarousel"
Position="{Binding CurrentCarouselIndex, Mode=TwoWay}"
Loop="False"
IsVisible="{Binding IsLoading, Converter={StaticResource boolToBoolInvertConverter}}"
ItemsSource="{Binding CarouselNewsList}"
Grid.Row="0"
IndicatorView="indicatorview">
<CarouselView.ItemTemplate>
<DataTemplate x:DataType="models:NewsModel">
<Border HeightRequest="150"
Padding="0"
Margin="0"
StrokeShape="RoundRectangle 10"
Stroke="Transparent">
<Grid>
<Image Source="{Binding NewsImageUrl, Converter={StaticResource imageResizerConverter}}"
Aspect="AspectFill"/>
<Grid Background="{StaticResource GradientBlack}">
<StackLayout VerticalOptions="End"
Spacing="5"
Padding="20,0,0,20">
<Label Text="{Binding NewsName}"
Grid.Row="1"
TextColor="{StaticResource White}"
FontSize="{StaticResource MiddleSize}"/>
<Label Text="{Binding NewsProvider}"
Grid.Row="2"
TextColor="{StaticResource White}"
FontSize="{StaticResource SmallSize}"/>
</StackLayout>
</Grid>
</Grid>
<Border.GestureRecognizers>
<TapGestureRecognizer Tapped="OnNewsItemTapped"/>
</Border.GestureRecognizers>
</Border>
</DataTemplate>
</CarouselView.ItemTemplate>
</CarouselView>
<IndicatorView x:Name="indicatorview"
IsVisible="{Binding IsLoading, Converter={StaticResource boolToBoolInvertConverter}}"
HorizontalOptions="End"
IndicatorColor="White"
IndicatorsShape="Circle"
MaximumVisible="6"
IndicatorSize="4"
Margin="20"
VerticalOptions="EndAndExpand"
SelectedIndicatorColor="#0F9D58"/>
Here is the View Model :
public partial class NewsViewModel : ObservableObject
{
[ObservableProperty]
private bool isFilterVisible;
[ObservableProperty]
private bool isSearchingNews;
[ObservableProperty]
private string userNewsLanguageCode;
[ObservableProperty]
private string newsTitlePage;
[ObservableProperty]
private string categoryToFilter;
[ObservableProperty]
private string searchNewsText;
[ObservableProperty]
private string searchNewsPlaceholder;
[ObservableProperty]
private string imageFiltered;
[ObservableProperty]
private int currentCarouselIndex;
public ObservableCollection<NewsModel> NewsList { get; set; }
public ObservableCollection<NewsModel> CarouselNewsList { get; set; }
public ObservableCollection<NewsModel> FilteredNewsList { get; set; }
private int _currentOffset = 0;
private const int _limit = 30;
public IAsyncRelayCommand LoadNewsCommand { get; }
public IAsyncRelayCommand LoadMoreNewsCommand { get; }
public ObservableCollection<NewsCountryListModel> MySortedDictionnaryLang { get; set; }
private ObservableCollection<NewsCountryListModel> _allLanguages;
public ObservableCollection<NewsCategoryListModel> MySortedDictionnaryNewsCategory { get; set; }
private ObservableCollection<NewsCategoryListModel> _allnewscategory;
[ObservableProperty]
private bool isLoadingCountry;
[ObservableProperty]
private bool isLoadingNewsCategory;
[ObservableProperty]
private string searchCloseImg;
[ObservableProperty]
private string cancelFilterLabel;
[ObservableProperty]
private string countriesLabel;
[ObservableProperty]
private string channelLabel;
private readonly UserDatabaseService _userdatabaseService;
[Obsolete]
public NewsViewModel(UserDatabaseService userdatabaseService)
{
_userdatabaseService = userdatabaseService;
var languageSettings = App.LanguageSettings;
searchCloseImg = "searchblackicon";
NewsTitlePage = languageSettings.NewsTitel;
ImageFiltered = "filterblack";
SearchNewsPlaceholder = languageSettings.SearchNews;
UserNewsLanguageCode = "en-US";
CancelFilterLabel = languageSettings.CancelFilterLabel;
CountriesLabel = languageSettings.Countries;
ChannelLabel = languageSettings.ChannelLabel;
MySortedDictionnaryLang = new ObservableCollection<NewsCountryListModel>();
_allLanguages = new ObservableCollection<NewsCountryListModel>();
MySortedDictionnaryNewsCategory = new ObservableCollection<NewsCategoryListModel>();
_allnewscategory = new ObservableCollection<NewsCategoryListModel>();
// CardsList Load data here
CarouselNewsList = new ObservableCollection<NewsModel>(); // Initialize the collection
NewsList = new ObservableCollection<NewsModel>(); // Initialize the collection
FilteredNewsList = new ObservableCollection<NewsModel>(); // Initialize the collection
LoadNewsCommand = new AsyncRelayCommand(LoadNewsAsync);
LoadMoreNewsCommand = new AsyncRelayCommand(LoadMoreNewsAsync);
LoadNewsCommand.Execute(null);
//InitializeAsync();
LoadCountryListCommand = new AsyncRelayCommand(LoadCountriesListAsync);
LoadCountryListCommand.Execute(null);
LoadNewsCategoryListCommand = new AsyncRelayCommand(LoadNewsCategoryListAsync);
LoadNewsCategoryListCommand.Execute(null);
MyFunctionShared.SetAppActivity(
MyVariablesClassApp.AppMenu.News.ToString(),
MyVariablesClassApp.AppSubMenu.GoPage.ToString());
// Subscribe to the NewsCountrySelectedMessage
WeakReferenceMessenger.Default.Register<NewsCountrySelectedMessage>(this, async (r, m) =>
{
UserNewsLanguageCode = m.Value.Code;
NumberAddedNews = 0;
ImageFiltered = "filterblack";
CategoryToFilter = string.Empty;
MyMvvMuser.NewsLanguage = UserNewsLanguageCode;
MyFunctionShared.UpdateUserInAllDatabse(MyMvvMuser);
LoadNewsCommand.Execute(null);
LoadNewsCategoryListCommand.Execute(null);
});
WeakReferenceMessenger.Default.Register<NewsCategorySelectedMessage>(this, async (r, m) =>
{
ImageFiltered = m.Value.CodeLower;
CategoryToFilter = m.Value.Code;
NumberAddedNews = 0;
LoadNewsCommand.Execute(null);
});
// Subscribe to the ClearCategoryFilterMessage
WeakReferenceMessenger.Default.Register<ClearCategoryFilterMessage>(this, (r, m) =>
{
CategoryToFilter = string.Empty;//m.Value;
ImageFiltered = "filterblack";
NumberAddedNews = 0;
LoadNewsCommand.Execute(null);
});
}
MyUser MyMvvMuser { get; set; }
async Task GetLocalDB()
{
MyMvvMuser = new MyUser();
MyMvvMuser = await _userdatabaseService.GetUserAsync();
if (!string.IsNullOrWhiteSpace(MyMvvMuser.NewsLanguage))
{
UserNewsLanguageCode = MyMvvMuser.NewsLanguage;
}
else
{
SetNewsLanguage(MyMvvMuser);
}
}
// Set News Language When the app start
void SetNewsLanguage(MyUser _tmpuser)
{
string UserLanguage = _tmpuser.LanguageKey2;
var phoneLanguage = CultureInfo.CurrentCulture.TwoLetterISOLanguageName;
var langDictionary = GetAppLanguageSetup.GetAppJsonNewsListOfLanguage(phoneLanguage);
var sortedLangDictionary = new SortedDictionary<string, string>(langDictionary);
// Find the first key that contains UserLanguage
string selectedLanguage = sortedLangDictionary.Keys
.FirstOrDefault(key => key.Contains(UserLanguage)) ?? "en-US";
_tmpuser.NewsLanguage = selectedLanguage;
UserNewsLanguageCode = MyMvvMuser.NewsLanguage;
}
public IAsyncRelayCommand LoadCountryListCommand { get; }
public IAsyncRelayCommand LoadNewsCategoryListCommand { get; }
public async Task LoadNewsCategoryListAsync()
{
IsLoadingNewsCategory = true;
await Task.Run(async () =>
{
var phoneLanguage = CultureInfo.CurrentCulture.TwoLetterISOLanguageName;
var langDictionaryNewsCategory = GetAppLanguageSetup.GetAppJsonNewsListCategory(phoneLanguage);
var sortedLangDictionaryCategory = new SortedDictionary<string, string>(langDictionaryNewsCategory);
// Get the unique categories
var uniqueCategories = await NewsDataAPIManager.GetNewsUniqueCategory(UserNewsLanguageCode);
// Filter the categories
var tempCollectionCategory = sortedLangDictionaryCategory
.Where(kvp => uniqueCategories.Contains(kvp.Key))
.Select(kvp => new NewsCategoryListModel { Code = kvp.Key, Name = kvp.Value })
.OrderBy(x => x.Name)
.ToList();
await MainThread.InvokeOnMainThreadAsync(() =>
{
MySortedDictionnaryNewsCategory.Clear();
_allnewscategory.Clear();
foreach (var item in tempCollectionCategory)
{
MySortedDictionnaryNewsCategory.Add(item);
_allnewscategory.Add(item);
}
IsLoadingNewsCategory = false;
});
});
}
public async Task LoadCountriesListAsync()
{
IsLoadingCountry = true;
await Task.Run(async () =>
{
var phoneLanguage = CultureInfo.CurrentCulture.TwoLetterISOLanguageName;
var langDictionary = GetAppLanguageSetup.GetAppJsonNewsListOfLanguage(phoneLanguage);
var sortedLangDictionary = new SortedDictionary<string, string>(langDictionary);
var tempCollection = sortedLangDictionary
.Select(kvp => new NewsCountryListModel { Code = kvp.Key, Name = kvp.Value })
.OrderBy(x => x.Name)
.ToList();
await MainThread.InvokeOnMainThreadAsync(() =>
{
MySortedDictionnaryLang.Clear();
_allLanguages.Clear();
foreach (var item in tempCollection)
{
MySortedDictionnaryLang.Add(item);
_allLanguages.Add(item);
}
IsLoadingCountry = false;
});
});
}
[ObservableProperty]
private bool isLoading;
private bool IsNewsExist;
int NumberAddedNews = 0;//Allow to add news in Carrousel
private async Task LoadNewsAsync()
{
IsLoading = true;
try
{
await GetLocalDB();
UserNewsLanguageCode = MyMvvMuser.NewsLanguage;
_currentOffset = 0;
var MyNewsData = await NewsDataAPIManager.LoadNewsDataAsync(UserNewsLanguageCode, CategoryToFilter, _currentOffset, _limit);
IsNewsExist = MyFunctionShared.IsListNotNullOrEmpty(MyNewsData);
await MainThread.InvokeOnMainThreadAsync(() =>
{
NewsList.Clear();
CarouselNewsList.Clear();
try
{
if (IsNewsExist)
{
foreach (var nw in MyNewsData)
{
if (NumberAddedNews <= 3)
{
// CarouselNewsList.Add(nw);
}
else
{
NewsList.Add(nw);
}
NumberAddedNews++;
}
_currentOffset += _limit;
}
}
catch (Exception ex)
{
Debug.WriteLine($"Theerror : {ex.Message}");
}
});
}
catch (Exception ex)
{
// Handle exceptions (e.g., log the error)
Console.WriteLine($"Error loading cards: {ex.Message}");
}
finally
{
IsLoading = false;
}
}
private bool isAddingCards = false;
private async Task LoadMoreNewsAsync()
{
// add condition to not enter here
if (isAddingCards == false)
{
try
{
isAddingCards = true;
var MyNewsData = await NewsDataAPIManager.LoadNewsDataAsync(UserNewsLanguageCode, CategoryToFilter, _currentOffset, _limit);
await MainThread.InvokeOnMainThreadAsync(() =>
{
foreach (var nw in MyNewsData)
{
NewsList.Add(nw);
}
});
_currentOffset += _limit;
}
catch (Exception ex)
{
// Handle exceptions (e.g., log the error)
Console.WriteLine($"Error loading more cards: {ex.Message}");
}
finally
{
isAddingCards = false;
}
}
}
[ObservableProperty]
private bool isNewsRefreshing;
[RelayCommand]
private async Task MyRefresh()
{
IsNewsRefreshing = true;
try
{
CategoryToFilter = string.Empty;//m.Value;
ImageFiltered = "filterblack";
NumberAddedNews = 0;
LoadNewsCommand.Execute(null);
}
finally
{
IsNewsRefreshing = false;
}
}
[Obsolete]
private void InitializeAsync()
{
AutoSwipeCarousel();
}
[Obsolete]
private void AutoSwipeCarousel()
{
Device.StartTimer(TimeSpan.FromSeconds(7), () =>
{
if (IsNewsExist == true)
{
CurrentCarouselIndex = (CurrentCarouselIndex + 1) % CarouselNewsList.Count;
return true; // Return true to keep the timer running
}
else
{
return true; // Return true to keep the timer running
}
});
}
}
Here is the cs code :
public partial class MyNewsPage : ContentPage
{
private NewsViewModel _viewModel;
[Obsolete]
public MyNewsPage()
{
InitializeComponent();
_viewModel = new NewsViewModel(App.UserDatabase);
BindingContext = _viewModel;
// Add this line to bind the CarouselView's position
// newsCarousel.SetBinding(CarouselView.PositionProperty, new Binding(nameof(NewsViewModel.CurrentCarouselIndex), BindingMode.TwoWay));
}
[Obsolete]
void OnShowBottonSheetFilterCountry(System.Object sender, System.EventArgs e)
{
MainThread.BeginInvokeOnMainThread(async () =>
{
var page = new NewsListCountryBottomSheet();
page.HasHandle = false;
await page.ShowAsync(Window);
});
MyFunctionShared.SetAppActivity(
MyVariablesClassApp.AppMenu.News.ToString(),
MyVariablesClassApp.AppSubMenu.ChangeCountryNews.ToString());
}
[Obsolete]
void OnShowBottonSheetFilterNews(System.Object sender, System.EventArgs e)
{
var viewModel = BindingContext as NewsViewModel;
MainThread.BeginInvokeOnMainThread(async () =>
{
var page = new NewsFilterCategoryBottomSheet(viewModel.UserNewsLanguageCode, viewModel.CategoryToFilter);
page.HasHandle = false;
await page.ShowAsync(Window);
});
MyFunctionShared.SetAppActivity(
MyVariablesClassApp.AppMenu.News.ToString(),
MyVariablesClassApp.AppSubMenu.FilteredNews.ToString());
}
UserNewsReadModel usernewsread;
async void OnNewsItemTapped(System.Object sender, System.EventArgs e)
{
var tappedItem = (sender as Border).BindingContext as NewsModel;
if (tappedItem != null && !string.IsNullOrEmpty(tappedItem.NewsUrl))
{
MainThread.BeginInvokeOnMainThread(async () =>
{
usernewsread = new UserNewsReadModel();
usernewsread.UserId = Preferences.Default.Get("MyUserId", "");
usernewsread.Language = tappedItem.Language;
usernewsread.NewsName = tappedItem.NewsName;
usernewsread.NewsUrl = tappedItem.NewsUrl;
usernewsread.NewsProvider = tappedItem.NewsProvider;
usernewsread.NewsImageUrl = tappedItem.NewsImageUrl;
usernewsread.NewsDate = tappedItem.NewsDate;
usernewsread.NewsCategory = tappedItem.NewsCategory;
usernewsread.LeafProvider = tappedItem.LeafProvider;
var page = new NewsBottomSheet(usernewsread);
page.HasHandle = false;
await page.ShowAsync(Window);
});
MyFunctionShared.SetAppActivity(
MyVariablesClassApp.AppMenu.News.ToString(),
MyVariablesClassApp.AppSubMenu.SeenNews.ToString());
}
}
protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
// Subscribe to the visibility changes
_viewModel.PropertyChanged += ViewModel_PropertyChanged;
}
private async void ViewModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName == nameof(NewsViewModel.IsSearchingNews))
{
if (_viewModel.IsSearchingNews)
{
await NewsMenuLayout.FadeTo(0, 250);
}
else
{
await NewsMenuLayout.FadeTo(1, 250);
}
}
}
/*
private void OnSearchTextChanged(object sender, TextChangedEventArgs e)
{
_viewModel.FilterNewsList(e.NewTextValue);
}*/
}
Here is the function to load the data :
int NumberAddedNews = 0;//Allow to add news in Carrousel
private async Task LoadNewsAsync()
{
IsLoading = true;
try
{
await GetLocalDB();
UserNewsLanguageCode = MyMvvMuser.NewsLanguage;
_currentOffset = 0;
var MyNewsData = await NewsDataAPIManager.LoadNewsDataAsync(UserNewsLanguageCode, CategoryToFilter, _currentOffset, _limit);
IsNewsExist = MyFunctionShared.IsListNotNullOrEmpty(MyNewsData);
await MainThread.InvokeOnMainThreadAsync(() =>
{
NewsList.Clear();
CarouselNewsList.Clear();
if (IsNewsExist)
{
foreach (var nw in MyNewsData)
{
if (NumberAddedNews <= 3)
{
CarouselNewsList.Add(nw); // got an error here when receiveing the message
}
else
{
NewsList.Add(nw);
}
NumberAddedNews++;
}
_currentOffset += _limit;
}
});
}
catch (Exception ex)
{
// Handle exceptions (e.g., log the error)
Console.WriteLine($"Error loading cards: {ex.Message}");
}
finally
{
IsLoading = false;
}
}
To reload the data I receive a message so that the data are reloaded :
// Subscribe to the NewsCountrySelectedMessage
WeakReferenceMessenger.Default.Register<NewsCountrySelectedMessage>(this, async (r, m) =>
{
UserNewsLanguageCode = m.Value.Code;
NumberAddedNews = 0;
ImageFiltered = "filterblack";
CategoryToFilter = string.Empty;
MyMvvMuser.NewsLanguage = UserNewsLanguageCode;
LoadNewsCommand.Execute(null);
});
My Problem : The reload work well on IOS but not on Android the app crash at the line " CarouselNewsList.Add(nw);" of the function LoadNewsAsync. I think it is a UI Issue and I do not see any error triggered