getItem
Returns the data item at the given position or null if it has not been loaded yet.
If this method has been called for a specific position and returned null, then onItemLoaded will be called when it finally loads. Note that if this position stays outside of the cached item range (as defined by extendRangeInto method), then the callback will never be called for this position.
Return
The data item at the given position or null if it has not been loaded yet.
Parameters
position
Item position.