它不会从 Fragment Activity 上的 Firebase 加载

Question

我在 Fragment 上创建了一个 Recycler View，将其与 Firebase 连接，但它不会在活动中显示任何内容，也不会从 Firebase 加载。我验证了代码和程序一千次，我真的不知道知道该怎么做，也许这是我的代码或连接中的问题..

片段类：

public class FragmentUnu extends Fragment {

  View v;

  FirebaseDatabase mDatabase;

  DatabaseReference mRef;

  RecyclerView mRecycler;

  RecyclerView.LayoutManager layoutManager;

  FirebaseRecyclerAdapter < FragmentUnuModel, FragmentUnuViewHolder > adapter;

  public FragmentUnu() {}

  @Override

  public View onCreateView(LayoutInflater inflater, ViewGroup container,

    Bundle savedInstanceState) {

    super.onCreateView(inflater, container, savedInstanceState);

    v = inflater.inflate(R.layout.unu_fragment, container, false);

    mRecycler = (RecyclerView) v.findViewById(R.id.fragment_unu_recycler);

    mRecycler.setHasFixedSize(true);

    layoutManager = new LinearLayoutManager(getActivity());

    mRecycler.setLayoutManager(layoutManager);

    mDatabase = FirebaseDatabase.getInstance();

    mRef = mDatabase.getReference("FragmentId");

    FirebaseRecyclerOptions < FragmentUnuModel > options = new FirebaseRecyclerOptions.Builder < FragmentUnuModel > ()

      .setQuery(mRef, FragmentUnuModel.class)

      .build();

    adapter = new FirebaseRecyclerAdapter < FragmentUnuModel, FragmentUnuViewHolder > (options) {

      @NonNull

      @Override

      public FragmentUnuViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View itemView = LayoutInflater.from(parent.getContext())

          .inflate(R.layout.unu_fragment_item, parent, false);

        return new FragmentUnuViewHolder(itemView);

      }

我在调试器中没有任何错误

Answer 1

您制作了适配器但没有将其分配给 RecyclerView。致电mRecycler.setAdapter()：... mRecycler.setAdapter(adapter); return&nbsp;v;

Answer 2

尝试在你的 onStart() 或 MainActivity 中调用它：&nbsp;adapter.notifyDataSetChanged();