void Element_OnScrollRequested(object sender, ScrollRequestedEventArgs e)
{
if (Element.ListLayout == HorizontalListViewLayout.Grid || Control.NumberOfItemsInSection(0) == 0 || e.Position >= Control.NumberOfItemsInSection(0))
{
return;
}
_isInternalScroll = true;
UICollectionViewScrollPosition type = UICollectionViewScrollPosition.Left;
switch (e.Type)
{
case ScrollType.Start:
type = UICollectionViewScrollPosition.Left;
break;
case ScrollType.End:
type = UICollectionViewScrollPosition.Right;
break;
case ScrollType.Center:
type = UICollectionViewScrollPosition.CenteredHorizontally;
break;
}
Control.ScrollToItem(
NSIndexPath.FromRowSection(e.Position, 0),
type,
e.Animate);
}
private void ScrollToCurrentItem()
{
if (Control == null ||
Element.CurrentIndex == -1 ||
Element.CurrentIndex >= Control.NumberOfItemsInSection(0) ||
Control.NumberOfItemsInSection(0) == 0)
{
return;
}
InternalLogger.Info($"ScrollToCurrentItem( Element.CurrentIndex = {Element.CurrentIndex} )");
_isInternalScroll = true;
Control.LayoutIfNeeded();
UICollectionViewScrollPosition position = UICollectionViewScrollPosition.Top;
if (Element.ListLayout == HorizontalListViewLayout.Linear)
{
switch (Element.SnapStyle)
{
case SnapStyle.Center:
position = UICollectionViewScrollPosition.CenteredHorizontally;
break;
case SnapStyle.Start:
position = UICollectionViewScrollPosition.Left;
break;
}
}
Control.ScrollToItem(
NSIndexPath.FromRowSection(Element.CurrentIndex, 0),
position,
false);
}
/// <summary>
/// Programatically select asset.
/// </summary>
/// <param name="index">Index.</param>
/// <param name="animated">If set to <c>true</c> animated.</param>
/// <param name="scrollPosition">Scroll position.</param>
public void SelectAsset(int index, bool animated, UICollectionViewScrollPosition scrollPosition)
{
var path = NSIndexPath.FromItemSection(index, LayoutConfiguration.SectionIndexForAssets);
CollectionView.SelectItem(path, animated, scrollPosition);
}
public virtual void ScrollToItemAtIndexPath(NSIndexPath indexPath, UICollectionViewScrollPosition atScrollPosition, bool animated)
{
}
public virtual void SelectItemAtIndexPath([Optional] NSIndexPath indexPath, bool animated, UICollectionViewScrollPosition scrollPosition)
{
}
public void ScrollToItem(NSIndexPath indexPath, UICollectionViewScrollPosition scrollPosition, bool animated) => collectionView.ScrollToItem(indexPath, scrollPosition, animated);