我是 Android 開發(fā)新手，并試圖將數(shù)據(jù)從 Firebase 數(shù)據(jù)庫顯示到 Recyclerview，但是當(dāng)我運(yùn)行該應(yīng)用程序時(shí)，用戶活動(dòng)為空白或在我的 RecyclerView 上沒有顯示任何內(nèi)容。我被卡住了，但輸出仍然相同：沒有顯示任何內(nèi)容。用戶活動(dòng)：private Toolbar mToolbar;private RecyclerView mUsersList;private DatabaseReference mUsersDatabase;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_users);    mToolbar = (Toolbar) findViewById(R.id.users_appBar);    setSupportActionBar(mToolbar);    getSupportActionBar().setTitle("Users");    getSupportActionBar().setDisplayHomeAsUpEnabled(true);    mToolbar.setTitleTextColor(Color.WHITE);    mToolbar.setSubtitleTextColor(Color.WHITE);    mUsersDatabase = FirebaseDatabase.getInstance().getReference().child("Users");    mUsersList = (RecyclerView) findViewById(R.id.users_list);    mUsersList.setHasFixedSize(true);    mUsersList.setLayoutManager(new LinearLayoutManager(this));}@Overrideprotected void onStart() {    super.onStart();    FirebaseRecyclerAdapter<Users, UsersViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Users, UsersViewHolder>(            Users.class,            R.layout.users_single_layout,            UsersViewHolder.class,            mUsersDatabase    ) {        @Override        protected void populateViewHolder(UsersViewHolder usersViewHolder, Users users, int i) {            usersViewHolder.setName(users.getName());        }    };    mUsersList.setAdapter(firebaseRecyclerAdapter);}public static class UsersViewHolder extends RecyclerView.ViewHolder{    View mView;    public UsersViewHolder(@NonNull View itemView) {        super(itemView);        mView = itemView;    }    public void setName(String name)    {        TextView userNameView = (TextView) mView.findViewById(R.id.user_name);        userNameView.setText(name);    }}