getItemPosition
Called when the host view is attempting to determine if an item's position has changed. Returns POSITION_UNCHANGED if the position of the given item has not changed or POSITION_NONE if the item is no longer present in the adapter.
The default implementation assumes that items will never change position and always returns POSITION_UNCHANGED.
Return
object's new position index from [0, getCount), POSITION_UNCHANGED if the object's position has not changed, or POSITION_NONE if the item is no longer present.
Parameters
object
Object representing an item, previously returned by a call to instantiateItem.