moveByOffset( offset , isSelecting, isSelectingRange)
- Return type: no return value
offset is positive, adjusts the focused item forward by that many items. If
offset is negative, adjusts the focused item backward by that many items. If
true, then the selection is also adjusted. If
isSelectingRange is also
true, then the new item is selected in addition to any currently selected items. If
false, any existing selection is cleared. Items that are hidden are skipped.