android - Firebase RecyclerView UI 未显示

Question

这个问题已经有答案了:

FirebaseListAdapter not pushing individual items for chat app - Firebase-Ui 3.1 (2 个回答)

已关闭 5 年前。

我一直在尝试实现firebase ui在我的应用程序中 recyclerview 。我的 firebase 数据库中有一些我想要使用 firebase ui recycler view 的项目。到目前为止，我认为我已经做对了一切，但是，当我运行我的应用程序时，它仍然显示空白。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:

The FirebaseRecyclerAdapter uses an event listener to monitor changes to the Firebase query. To begin listening for data, call the startListening() method. You may want to call this in your onStart() method. Make sure you have finished any authentication necessary to read the data before calling startListening() or your query will fail.

@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