private void updateFloatView() {

        if (mFloatViewManager != null) {
            mTouchLoc.set(mX, mY);
            mFloatViewManager.onDragFloatView(mFloatView, mFloatLoc, mTouchLoc);
        }

        final int floatX = mFloatLoc.x;
        final int floatY = mFloatLoc.y;

        // restrict x motion
        int padLeft = getPaddingLeft();
        if ((mDragFlags & DRAG_POS_X) == 0 && floatX > padLeft) {
            mFloatLoc.x = padLeft;
        } else if ((mDragFlags & DRAG_NEG_X) == 0 && floatX < padLeft) {
            mFloatLoc.x = padLeft;
        }

        // keep floating view from going past bottom of last header view
        final int numHeaders = getHeaderViewsCount();
        final int numFooters = getFooterViewsCount();
        final int firstPos = getFirstVisiblePosition();
        final int lastPos = getLastVisiblePosition();

        // Log.d("mobeta",
        // "nHead="+numHeaders+" nFoot="+numFooters+" first="+firstPos+" last="+lastPos);
        int topLimit = getPaddingTop();
        if (firstPos < numHeaders) {
            topLimit = getChildAt(numHeaders - firstPos - 1).getBottom();
        }
        if ((mDragFlags & DRAG_NEG_Y) == 0) {
            if (firstPos <= mSrcPos) {
                topLimit = Math.max(getChildAt(mSrcPos - firstPos).getTop(), topLimit);
            }
        }
        // bottom limit is top of first footer View or
        // bottom of last item in list
        int bottomLimit = getHeight() - getPaddingBottom();
        if (lastPos >= getCount() - numFooters - 1) {
            bottomLimit = getChildAt(getCount() - numFooters - 1 - firstPos).getBottom();
        }
        if ((mDragFlags & DRAG_POS_Y) == 0) {
            if (lastPos >= mSrcPos) {
                bottomLimit = Math.min(getChildAt(mSrcPos - firstPos).getBottom(), bottomLimit);
            }
        }

        // Log.d("mobeta", "dragView top=" + (y - mDragDeltaY));
        // Log.d("mobeta", "limit=" + limit);
        // Log.d("mobeta", "mDragDeltaY=" + mDragDeltaY);

        if (floatY < topLimit) {
            mFloatLoc.y = topLimit;
        } else if (floatY + mFloatViewHeight > bottomLimit) {
            mFloatLoc.y = bottomLimit - mFloatViewHeight;
        }

        // get y-midpoint of floating view (constrained to ListView bounds)
        mFloatViewMid = mFloatLoc.y + mFloatViewHeightHalf;
    }
Sets float View location based on suggested values and
constraints set in mDragFlags.
third_party/DragSortListView/src/com/mobeta/android/dslv/DragSortListView.java