Firebase RecyclerView UI 未显示 [重复]

Question

我一直在尝试使用recyclerview 在我的应用程序中实现firebase ui。我的 firebase 数据库中有我想使用firebase ui recycler view 的项目。到目前为止，我认为我做的一切都是正确的，但是，当我运行我的应用程序时，它仍然显示为空白。任何帮助将不胜感激。

public class UsersActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private Query query;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_users);
        query = FirebaseDatabase.getInstance().getReference().child("Users");
        mRecyclerView = findViewById(R.id.recycler_view);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    }

    @Override
    protected void onStart() {
        super.onStart();
        FirebaseRecyclerOptions <Users> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<Users>()
                .setQuery(query, Users.class).build();
        FirebaseRecyclerAdapter firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Users, UsersViewHolder>(firebaseRecyclerOptions){

            @NonNull
            @Override
            public UsersViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                View mView = LayoutInflater.from(parent.getContext()).inflate(R.layout.users_single_layout, parent,false);
                return new UsersViewHolder(mView);
            }

            @Override
            protected void onBindViewHolder(@NonNull UsersViewHolder holder, int position, @NonNull Users model) {
                holder.setName(model.getName());

            }
        };
        mRecyclerView.setAdapter(firebaseRecyclerAdapter);
    }
    public static class UsersViewHolder extends RecyclerView.ViewHolder{
View mView;
        UsersViewHolder(View itemView) {
            super(itemView);
            mView = itemView;
        }
        public void setName (String name){
            TextView mName = mView.findViewById(R.id.user_name);
            mName.setText(name);
        }
    }
}

Answer 1

您需要添加以下内容：

FirebaseRecyclerAdapter 使用事件侦听器来监控 Firebase 查询的更改。要开始侦听数据，请调用startListening() 方法。您可能想在 onStart() 方法中调用它。在调用startListening() 之前，请确保您已完成读取数据所需的任何身份验证，否则您的查询将失败。

@Override
protected void onStart() {
super.onStart();
firebaseRecyclerAdapter.startListening();
}

@Override
protected void onStop() {
super.onStop();
firebaseRecyclerAdapter.stopListening();
 }

更多信息在这里：

https://github.com/firebase/FirebaseUI-Android/tree/master/database