title: How do you set an Expandable Recycler View's parent views to be expanded by default
body: <p>I have an expandable recycler view, and it is displayed when my activity is started. However by default the parent views are collapsed.</p>
  
  <p>I have tried setting setExpanded(true) inside my parent view holder like so:</p>
  
  <pre><code>public PersonParentViewHolder(View itemView) {
      super(itemView);
  
      mPersonTitleTextView = (TextView) itemView.findViewById(R.id.parent_list_item_person_title_text_view);
      mParentDropDownArrow = (ImageButton) itemView.findViewById(R.id.parent_list_item_expand_arrow);
      setExpanded(true);
  }
  </code></pre>
  
  <p>But that does not seem to help. </p>
  
  <p>This is the creation of the ParentViewHolder</p>
  
  <pre><code>@Override
  public PersonParentViewHolder onCreateParentViewHolder(ViewGroup viewGroup) {
      View view = mInflater.inflate(R.layout.person_parent_layout, viewGroup, false);
  
      return new PersonParentViewHolder(view);
  }
  </code></pre>
  
  <p>Here is where the recycler view is created if that helps at all</p>
  
  <pre><code>@Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
                           Bundle savedInstanceState) {
      // Inflate the layout for this fragment
      View view = inflater.inflate(R.layout.person_fragment_layout, container, false);
  
      recyclerView = (RecyclerView) view
              .findViewById(R.id.person_recycler_view);
      recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
  
      updateUI(view);
  
      return view;
  }
  </code></pre>
  
  <p>Thanks in advance!</p>