public OnControlScrollChangedListener(
CollectionViewRenderer nativeView,
CollectionView.RenderedViews.CollectionView element)
{
_weakNativeView = new WeakReference <CollectionViewRenderer>(nativeView);
_element = element;
}
private void UpdateCurrentIndex(
CollectionViewRenderer nativeView,
CancellationToken token)
{
if (token.IsCancellationRequested)
{
return;
}
if (nativeView?.LinearLayoutManager == null || _element == null)
{
return;
}
nativeView._isCurrentIndexUpdateBackfire = true;
try
{
int newIndex = -1;
if (_element.SnapStyle != SnapStyle.None)
{
newIndex = nativeView.CurrentSnapIndex;
}
else
{
newIndex = nativeView.LinearLayoutManager.FindFirstCompletelyVisibleItemPosition();
if (newIndex == -1)
{
newIndex = nativeView.LinearLayoutManager.FindFirstVisibleItemPosition();
}
}
if (newIndex == -1)
{
InternalLogger.Warn(
"Failed to find the current index: UpdateCurrentIndex returns nothing");
return;
}
_element.CurrentIndex = newIndex;
InternalLogger.Info($"CurrentIndex: {_element.CurrentIndex}");
}
finally
{
nativeView._isCurrentIndexUpdateBackfire = false;
}
}
public StartSnapHelper(CollectionViewRenderer nativeView)
: base(nativeView)
{
}
public CenterSnapHelper(CollectionViewRenderer nativeView)
{
WeakNativeView = new WeakReference <CollectionViewRenderer>(nativeView);
}
public RecycleViewAdapter(CollectionView.RenderedViews.CollectionView element, CollectionViewRenderer nativeView, RecyclerView parentView, Context context)
{
_element = element;
_weakNativeView = new WeakReference <CollectionViewRenderer>(nativeView);
_weakParentView = new WeakReference <RecyclerView>(parentView);
_context = context;
_elementItemsSource = element.ItemsSource;
_dataSource = _elementItemsSource?.Cast <object>().ToList() ?? new List <object>();
_formsViews = new List <WeakReference <ViewCell> >();
if (_element.ItemTemplate is not DataTemplateSelector)
{
// Cache only support single DataTemplate
_viewHolderQueue = new ViewHolderQueue(element.ViewCacheSize, () => CreateViewHolder());
_viewHolderQueue.Build();
}
_notifyCollectionChanged = _elementItemsSource as INotifyCollectionChanged;
if (_notifyCollectionChanged != null)
{
_notifyCollectionChanged.CollectionChanged += OnCollectionChanged;
}
}