protected override void OnLayout(bool changed, int left, int top, int right, int bottom)
{
base.OnLayout(changed, left, top, right, bottom);
if (!changed)
{
return;
}
var startPos = _layoutManager.FindFirstCompletelyVisibleItemPosition();
var endPos = _layoutManager.FindLastCompletelyVisibleItemPosition();
int totalH = 0;
for (var i = startPos; i <= endPos; i++)
{
var child = _layoutManager.GetChildAt(i);
if (child == null)
{
return;
}
totalH += _layoutManager.GetChildAt(i).Height;
}
Element.VisibleContentHeight = Context.FromPixels(Math.Min(totalH, Control.Height));
}
public override void OnScrolled(RecyclerView recyclerView, int dx, int dy)
{
base.OnScrolled(recyclerView, dx, dy);
LinearLayoutManager manager = (LinearLayoutManager)recyclerView.GetLayoutManager();
//获取最后一个完全显示的itemPosition
int lastItemPosition = manager.FindLastCompletelyVisibleItemPosition();
int itemCount = manager.ItemCount;
// 判断是否滑动到了最后一个item
if (lastItemPosition == (itemCount - 3))
{
//加载更多
onLoadMore();
}
}
public override void OnScrolled(Android.Support.V7.Widget.RecyclerView recyclerView, int dx, int dy)
{
LinearLayoutManager layoutManager = (LinearLayoutManager)recyclerView.GetLayoutManager();
int firstVisible = layoutManager.FindFirstVisibleItemPosition();
int visibleCount = Math.Abs(firstVisible - layoutManager.FindLastCompletelyVisibleItemPosition());
int itemCount = recyclerView.GetAdapter().ItemCount;
if (firstVisible != _lastFirstVisible || visibleCount != _lastVisibleCount || itemCount != _lastItemCount)
{
_scrollListener.OnScroll(null, firstVisible, visibleCount, itemCount);
_lastVisibleCount = firstVisible;
_lastVisibleCount = visibleCount;
_lastItemCount = itemCount;
}
}
public override void OnScrolled(RecyclerView recyclerView, int dx, int dy)
{
base.OnScrolled(recyclerView, dx, dy);
if (viewModel.IsBusy || viewModel.Trips.Count == 0 || !viewModel.CanLoadMore)
{
return;
}
var lastVisiblePosition = layoutManager.FindLastCompletelyVisibleItemPosition();
if (lastVisiblePosition == RecyclerView.NoPosition)
{
return;
}
//if we are at the bottom and can load more.
if (lastVisiblePosition == viewModel.Trips.Count - 1)
{
viewModel.LoadMorePastTripCommand.Execute(null);
}
}
private int GetLastCompletelyVisibleItemPosition()
{
return(mLayoutManager.FindLastCompletelyVisibleItemPosition());
}