在Recycler视图中向上滚动？

Question

我想实现向上滚动并使用回收站视图向下滚动。如果正常则向下滚动，但我不知道如何向上滚动？

recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        Log.e(TAG,"Onscrolled");
    }

    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        Log.e(TAG,"State"+newState);
        if (newState==2) {
            //do scroll down
        }                           
    }
});