尝试在Recyclerview中显示用户信息-Firebase [英] Trying to display users information in a recyclerview - Firebase

问题描述

我的应用正在使用Firebase.用户可以注册和登录.在主要活动中，有一个名为所有用户的菜单选项.我现在想要的只是在recyclerview中显示注册的用户.当然，这意味着我将不得不使用

My app is using Firebase. The user can register and login. In the main activity, there is a menu option called All Users. All I want for now is to display the registered users in a recyclerview. Of course this means that I will have to query the database using

    mUsersDatabase = FirebaseDatabase.getInstance().getReference().child("Users");

如果我在此行中设置断点，则可以读取用户.没关系.

If I put a breakpoint in this line, I can read the users. That's no problem.

接下来，我将这个页面用于实施 FirebaseRecyclerAdapter

Next, I use this page to implement the FirebaseRecyclerAdapter

完整代码如下所示.

public class UsersActivity extends AppCompatActivity {
private Toolbar mToolbar;
private RecyclerView mUserList;
private DatabaseReference mUsersDatabase;

private FirebaseRecyclerOptions<Users> options;
private FirebaseRecyclerAdapter firebaseRecyclerAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_users);

    mToolbar = (Toolbar)findViewById(R.id.users_appBar);
    setSupportActionBar(mToolbar);
    getSupportActionBar().setTitle("All Users");
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    mUsersDatabase = FirebaseDatabase.getInstance().getReference().child("Users");

    mUserList = (RecyclerView)findViewById(R.id.users_list);
    mUserList.setHasFixedSize(true);
    mUserList.setLayoutManager(new LinearLayoutManager(this));

}

@Override
protected void onStart() {
    super.onStart();

    options =
            new FirebaseRecyclerOptions.Builder<Users>()
            .setQuery(mUsersDatabase, Users.class)
            .build();


    firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Users, UsersViewHolder>(options) {

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

            return new UsersViewHolder(view);
        }

        @Override
        protected void onBindViewHolder(UsersViewHolder usersViewHolder, int i,Users users) {
            usersViewHolder.setName(users.getName());
        }
    };
    mUserList.setAdapter(firebaseRecyclerAdapter);

}


public static class UsersViewHolder extends RecyclerView.ViewHolder{

    View mView;

    public UsersViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
        }

    public void setName (String name){
        TextView userNameView = (TextView) mView.findViewById(R.id.singleUserName);
        userNameView.setText(name);
    }
  }
}

但是，不显示用户.为什么会这样?

However, users are not displayed. Why is this happening?

谢谢

Theo.

推荐答案

如链接页面中所述，您需要执行以下操作:

As explained in the page that you linked, you need to do the following:

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

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

您需要添加startListening()才能开始侦听数据，并且stopListening()调用将删除事件侦听器和适配器中的所有数据.

You need to add startListening() to begin listening for data, and the stopListening() call removes the event listener and all data in the adapter.

这篇关于尝试在Recyclerview中显示用户信息-Firebase的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！