question: private View fillUp ( int pos , int nextBottom ) { if ( DEBUG ) Log . i ( TAG , "fillLeft() pos: " + pos + " nextBottom: " + nextBottom + M_FIRST_POSITION + mFirstPosition ) ; View selectedView = null ; final int end = mListPadding . top ; while ( nextBottom > end && pos >= 0 ) { View temp = makeRow ( pos , nextBottom , false ) ; if ( temp != null ) { selectedView = temp ; } nextBottom = mReferenceView . getTop ( ) - mVerticalSpacing ; mFirstPosition = pos ; pos -= mNumColumns ; } if ( mStackFromBottom ) { mFirstPosition = Math . max ( 0 , pos + 1 ) ; } return selectedView ; }
target:  Fills the list from pos up to the top of the list view.