Error

ConversasFragment.java

/**
 * A simple {@link Fragment} subclass.
 */
public class ConversasFragment extends Fragment {

    private RecyclerView recyclerViewConversas;
    private List<Conversa> listaConversas = new ArrayList<>();
    private ConversasAdapter adapter;
    private DatabaseReference database;
    private DatabaseReference conversasRef;
    private ChildEventListener childEventListenerConversas;
    //private ValueEventListener valueEventListenerConversas;

    public ConversasFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_conversas, container, false);

        //Configuracoes Iniciais
        recyclerViewConversas = view.findViewById(R.id.conversas_recyclerview);
        String identificadorUsuario = UsuarioFirebase.getIdentificadorUsuario();
        database = ConfiguracaoFirebase.getFirebaseDatabase();
        conversasRef = database.child("conversas")
                .child(identificadorUsuario);

        // Adapter
        adapter = new ConversasAdapter(listaConversas, getActivity());

        //RecyclerView
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
        recyclerViewConversas.setLayoutManager(layoutManager);
        recyclerViewConversas.setHasFixedSize(true);
        recyclerViewConversas.setAdapter(adapter);


        //  Configurar Cliques
        recyclerViewConversas.addOnItemTouchListener(
                new RecyclerItemClickListener(
                        getActivity(),
                        recyclerViewConversas,
                        new RecyclerItemClickListener.OnItemClickListener() {
                            @Override
                            public void onItemClick(View view, int position) {
                                Conversa conversaSelecionada = listaConversas.get(position);

                                Intent intent = new Intent(getActivity(), ChatActivity.class);
                                intent.putExtra("chatContacto", conversaSelecionada.getUsuarioExibicao());
                                startActivity(intent);
                            }

                            @Override
                            public void onLongItemClick(View view, int position) {

                            }

                            @Override
                            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                            }
                        }));

        return view;
    }

    @Override
    public void onStart() {
        super.onStart();

        Log.d("tamanho Start Antes", String.valueOf(listaConversas.size()));
        listaConversas.clear();
        recuperarConversas();
        Log.d("tamanho Start Dep.", String.valueOf(listaConversas.size()));
    }

    @Override
    public void onStop() {
        super.onStop();
        //conversasRef.removeEventListener(childEventListenerConversas);
        conversasRef.removeEventListener(childEventListenerConversas);
    }

    public void pesquisarConversa(String texto) {
        List<Conversa> listaConversaBusca = new ArrayList<>();
        for (Conversa conversa : listaConversas) {
             Log.d("tamanho pesq.", String.valueOf(listaConversas.size()));
            String nome = conversa.getUsuarioExibicao().getNome();
            String ultimaMsg = conversa.getUltimaMensagem();

            if (nome.contains(texto) || ultimaMsg.contains(texto)) {
                listaConversaBusca.add(conversa);
            }
        }

        adapter = new ConversasAdapter(listaConversaBusca, getActivity());
        recyclerViewConversas.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }

    public void recuperarConversas() {

        childEventListenerConversas = conversasRef.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
                //Recuperar conversas
                Conversa conversa = dataSnapshot.getValue(Conversa.class);
                listaConversas.add(conversa);
                adapter.notifyDataSetChanged();
                Log.d("tamanho da lista", String.valueOf(listaConversas.size()));

            }

            @Override
            public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {

            }

            @Override
            public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {

            }

            @Override
            public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {

            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

/*        valueEventListenerConversas = conversasRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for(DataSnapshot dados: dataSnapshot.getChildren()){
                    Conversa conversa = dados.getValue(Conversa.class);
                    listaConversas.add(conversa);
                }
                adapter.notifyDataSetChanged();
                Log.d("tamanho recuperaV", String.valueOf(listaConversas.size()));
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });*/


    }




}

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setAdapter(android.support.v7.widget.RecyclerView$Adapter)' on a null object reference at com.example.dowy.chat.fragment.ConversasFragment.pesquisarConversa(ConversasFragment.java:133) at com.example.dowy.chat.activity.MainActivity$2.onQueryTextChange(MainActivity.java:82)