public void OnScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
System.Diagnostics.Debug.WriteLine(firstVisibleItem);
if (firstVisibleItem + visibleItemCount == totalItemCount) // Clear items, add from current half way to chunk size after last item, scroll back to old last item
{
var firstItem = adapter.GetItem(chunksize);
adapter.Clear();
for (int i = 0; i < chunksize * 2; i++)
{
adapter.Add(firstItem.AddDays(i));
}
adapter.NotifyDataSetChanged();
view.SetSelection(chunksize - visibleItemCount - 1);
}
else if (firstVisibleItem == 0) // Clear items, add from chunk size before first item, scroll back to old first item
{
var lastItem = adapter.GetItem(chunksize);
adapter.Clear();
for (int i = chunksize * 2 - 1; i >= 0; i--)
{
adapter.Add(lastItem.AddDays(-i));
}
adapter.NotifyDataSetChanged();
view.SetSelection(chunksize - 1);
}
}
/// <summary>
/// Bind this class to the goto top button in the parent view
/// </summary>
/// <param name="parentView"></param>
/// <param name="listView"></param>
public void BindControl(View parentView, AbsListView listView)
{
if (parentView != null)
{
fab = parentView.FindViewById <FloatingActionButton>(Resource.Id.goto_top_button);
if (fab != null)
{
// Hide the button initially
fab.Visibility = ViewStates.Gone;
// Hook into the listview's scroll events
listView.SetOnScrollListener(this);
// Scroll back to the top when the button is clicked
fab.Click += (sender, e) =>
{
if (listView.FirstVisiblePosition > 20)
{
listView.SetSelection(20);
}
listView.SmoothScrollToPosition(0);
};
}
}
else
{
fab = null;
}
}
