class LinearLayoutManager extends RecyclerView.LayoutManager implements
        ItemTouchHelper.ViewDropHandler, RecyclerView.SmoothScroller.ScrollVectorProvider {

    @Override
    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state,
            int position) {
        LinearSmoothScroller linearSmoothScroller =
                new LinearSmoothScroller(recyclerView.getContext());
        linearSmoothScroller.setTargetPosition(position);
        startSmoothScroll(linearSmoothScroller);
    }

    public  LinearLayoutManager(Context context);
    public  LinearLayoutManager(Context context, @RecyclerView.Orientation int orientation,
            boolean reverseLayout);
    public  LinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr,
            int defStyleRes);

}