protected override void OnElementChanged(ElementChangedEventArgs <ListView> e)
{
_requestedScroll = null;
if (e.OldElement != null)
{
var controller = (IListViewController)e.OldElement;
var headerView = (VisualElement)controller.HeaderElement;
if (headerView != null)
{
headerView.MeasureInvalidated -= OnHeaderMeasureInvalidated;
}
var footerView = (VisualElement)controller.FooterElement;
if (footerView != null)
{
footerView.MeasureInvalidated -= OnFooterMeasureInvalidated;
}
controller.ScrollToRequested -= OnScrollToRequested;
var templatedItems = ((ITemplatedItemsView <Cell>)e.OldElement).TemplatedItems;
templatedItems.CollectionChanged -= OnCollectionChanged;
templatedItems.GroupedCollectionChanged -= OnGroupedCollectionChanged;
}
if (e.NewElement != null)
{
if (Control == null)
{
_tableViewController = new FormsUITableViewController(e.NewElement);
SetNativeControl(_tableViewController.TableView);
if (Forms.IsiOS9OrNewer)
{
Control.CellLayoutMarginsFollowReadableWidth = false;
}
_insetTracker = new KeyboardInsetTracker(_tableViewController.TableView, () => Control.Window, insets => Control.ContentInset = Control.ScrollIndicatorInsets = insets, point =>
{
var offset = Control.ContentOffset;
offset.Y += point.Y;
Control.SetContentOffset(offset, true);
});
}
_shouldEstimateRowHeight = true;
var controller = (IListViewController)e.NewElement;
controller.ScrollToRequested += OnScrollToRequested;
var templatedItems = ((ITemplatedItemsView <Cell>)e.NewElement).TemplatedItems;
templatedItems.CollectionChanged += OnCollectionChanged;
templatedItems.GroupedCollectionChanged += OnGroupedCollectionChanged;
UpdateRowHeight();
Control.Source = _dataSource = e.NewElement.HasUnevenRows ? new UnevenListViewDataSource(e.NewElement, _tableViewController) : new ListViewDataSource(e.NewElement, _tableViewController);
UpdateEstimatedRowHeight();
UpdateHeader();
UpdateFooter();
UpdatePullToRefreshEnabled();
UpdateIsRefreshing();
UpdateSeparatorColor();
UpdateSeparatorVisibility();
var selected = e.NewElement.SelectedItem;
if (selected != null)
{
_dataSource.OnItemSelected(null, new SelectedItemChangedEventArgs(selected));
}
}
base.OnElementChanged(e);
}
