getItemRangeInto
Compute the range of visible item positions.
outRange[0] is the position of the first visible item (in the order of the backing storage).
outRange[1] is the position of the last visible item (in the order of the backing storage).
Negative positions and positions greater or equal to getItemCount are invalid. If the returned range contains invalid positions it is ignored (no item will be loaded).
Parameters
outRange
The visible item range.