async void Handle_ScrollMessagesEvent(object sender, System.EventArgs e)
{
if (e is ScrollEventArgs args)
{
if (_viewModel.IsActive)
{
ChatMessagesListView.LayoutManager.ScrollToRowIndex(args.Index, args.ScrollPosition, !args.Animated);
if (ChatMessagesListView.Opacity <= 0)
{
await Task.Delay(75);
if (_viewModel.IsActive)
{
await ChatMessagesListView.FadeTo(1, 275, Easing.CubicInOut);
}
}
}
}
}
public ChatPage()
{
InitializeComponent();
ChatMessagesListView.LayoutManager.ItemsCacheLimit = 2;
_viewModel = (BindingContext as ChatPageViewModel);
_viewModel.PropertyChanged += ViewModel_PropertyChanged;
_viewModel.ScrollMessagesEvent += Handle_ScrollMessagesEvent;
_visualContainer = ChatMessagesListView.GetVisualContainer();
_visualContainer.ScrollRows.Changed += ScrollRows_Changed;
_scrollView = ChatMessagesListView.GetScrollView();
_scrollView.SetBinding(Xamarin.Forms.ScrollView.ContentSizeProperty, "ScrollViewSize");
_scrollView.SetBinding(Xamarin.Forms.ScrollView.ScrollYProperty, "ScrollY");
ChatMessagesListView.SetBinding(HeightProperty, "ScrollViewHeight");
ChatMessagesListView.Opacity = 0;
Messages = new ObservableCollection <ChatMessage>();
}