Scroll to middle item Immediately

[IbrahimDisouki]

How i can scroll to middle item Immediately ? I tried this but did not work

case R.id.linear_horizontal:
                mRecyclerView.setAdapter(new DemoAdapter(R.layout.linear_horizontal));
                mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));
                mRecyclerView.center(DemoAdapter.MIDDLE_ITEM); // scrolled but not centered.