private void clearPositions() {
        mSrcPos = -1;
        mFirstExpPos = -1;
        mSecondExpPos = -1;
        mFloatPos = -1;
    }
Cancel a drag. Calls {@link #stopDrag(boolean, boolean)} with
<code>true</code> as the first argument.
third_party/DragSortListView/src/com/mobeta/android/dslv/DragSortListView.java