为什么我不能使用populateViewHolder覆盖方法？

Question

我试图从我使用FirebaseRecylerAdapter的方法中检索数据database，如下所示fragment onViewCreated

@Override

    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {

        super.onViewCreated(view, savedInstanceState);

        FirebaseRecyclerAdapter<AllUsers, AllUsersViewHolder> firebaseRecyclerAdapter;

    }

    public static class AllUsersViewHolder extends RecyclerView.ViewHolder {

        View view;

        public AllUsersViewHolder(View itemView) {

            super(itemView);

            view = itemView;

        }

    }

当我使用firebaseRecyclerAdapter = new FirebaseRecyclerAdapter它不会给我populateViewHolder方法只是给下面的方法

FirebaseRecyclerAdapter<AllUsers, AllUsersViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<AllUsers, AllUsersViewHolder>() {

            @Override

            protected void onBindViewHolder(AllUsersViewHolder holder, int position, AllUsers model) {

            }

            @Override

            public AllUsersViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

                return null;

            }

        };

有人可以告诉我为什么会这样吗