library/src/com/handmark/pulltorefresh/library/OverscrollHelper.java
public static void overScrollBy(final PullToRefreshBase<?> view, final int deltaX, final int scrollX,
			final int deltaY, final int scrollY, final boolean isTouchEvent) {
		overScrollBy(view, deltaX, scrollX, deltaY, scrollY, 0, isTouchEvent);
	}
public static void overScrollBy(final PullToRefreshBase<?> view, final int deltaX, final int scrollX,
			final int deltaY, final int scrollY, final boolean isTouchEvent) {
		overScrollBy(view, deltaX, scrollX, deltaY, scrollY, 0, isTouchEvent);
	}
Helper method for Overscrolling that encapsulates all of the necessary
function.
<p/>
This should only be used on AdapterView's such as ListView as it just
calls through to overScrollBy() with the scrollRange = 0. AdapterView's
do not have a scroll range (i.e. getScrollY() doesn't work).

@param view - PullToRefreshView that is calling this.
@param deltaX - Change in X in pixels, passed through from from
overScrollBy call
@param scrollX - Current X scroll value in pixels before applying deltaY,
passed through from from overScrollBy call
@param deltaY - Change in Y in pixels, passed through from from
overScrollBy call
@param scrollY - Current Y scroll value in pixels before applying deltaY,
passed through from from overScrollBy call
@param isTouchEvent - true if this scroll operation is the result of a
touch event, passed through from from overScrollBy call