title: How to detect when RecyclerView is scrolled to most top position
body: <p>I have RecyclerView above that i have an AppBarLayout whose height is larger than 255 px. When user scrolls RecyclerView, AppBarLayout has an fling issue. To avoid that i decided to expand AppBarLayout manually. My RecyclerView made of GridLayoutManager with span of 3. I used below code to listen RecyclerView top reach</p>
  
  <pre><code>recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
      @Override
      public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
          super.onScrollStateChanged(recyclerView, newState);
          if (newState == RecyclerView.SCROLL_STATE_IDLE) {
              int firstVisiblePosition = ((LinearLayoutManager)recyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition();
              if (firstVisiblePosition == 0) {
                  appBarLayout.setExpanded(true, true);
              }
          }
      }
  });
  </code></pre>