如何将Firebase数据正确实现到Recyclerview中？

Question

我一直在测试如何将Firebase Realtime数据库中的数据实现到我的recyclerviews中。

我在oncreate中添加了Firebasedatabase.getInstance（）。getReference。但是它似乎没有为我提供我需要输入到recyclerview的数据

import android.os.Bundle;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import java.util.ArrayList;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import sg.edu.tp.soundup.Adapters.RecyclerViewDataAdapter;
import sg.edu.tp.soundup.Models.SectionDataModel;
import sg.edu.tp.soundup.Models.SingleItemModel;

public class Main_act extends AppCompatActivity {
private static final String TAG = "Main_act";

private ArrayList<SectionDataModel> listItem;

DatabaseReference Data;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_act);

    listItem = new ArrayList<>();
    Data = FirebaseDatabase.getInstance().getReference("Data");

    createDummyData();

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
        recyclerView.setHasFixedSize(true);
        RecyclerViewDataAdapter adapter = new RecyclerViewDataAdapter(listItem, this);
        recyclerView.setLayoutManager(new LinearLayoutManager(this, RecyclerView.VERTICAL, false));
        recyclerView.setAdapter(adapter);
}


    private void createDummyData() {
    for (int i = 1; i <= 5; i++) {
        SectionDataModel dm = new SectionDataModel();
        dm.setHeaderTitle("Section " + i);
        ArrayList<SingleItemModel> singleItemModels = new ArrayList<>();
        for (int j = 1; j <= 5; j++) {
            singleItemModels.add(new SingleItemModel("Item " + j, "art " + j));
        }
        dm.setAllItemInSection(singleItemModels);
        listItem.add(dm);
    }

}

}

public class SingleItemModel {
public String name, art;

public SingleItemModel() {

}

public SingleItemModel(String name, String art) {
    this.name = name;
    this.art = art;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getart() {
    return art;
}

public void setart(String art) {
    this.art = art;
}

}

import java.util.ArrayList;

public class SectionDataModel {
private String headerTitle;
private ArrayList<SingleItemModel> listItem;

public SectionDataModel() {
}

public SectionDataModel(String headerTitle, ArrayList<SingleItemModel> listItem) {
    this.headerTitle = headerTitle;
    this.listItem = listItem;
}

public String getHeaderTitle() {
    return headerTitle;
}

public void setHeaderTitle(String headerTitle) {
    this.headerTitle = headerTitle;
}

public ArrayList<SingleItemModel> getAllItemInSection() {
    return listItem;
}

public void setAllItemInSection(ArrayList<SingleItemModel> allItemInSection) {
    this.listItem = allItemInSection;
}

}

public class SectionListDataAdapter extends 
RecyclerView.Adapter<SectionListDataAdapter.SingleItemRowHolder>{

    private ArrayList<SingleItemModel> itemModels;
    private Context mContext;

    public SectionListDataAdapter(ArrayList<SingleItemModel> itemModels, Context mContext) {
    this.itemModels = itemModels;
    this.mContext = mContext;
}

    @Override
    public SingleItemRowHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_single_card, null);
        SingleItemRowHolder singleItemRowHolder = new SingleItemRowHolder(v);
        return singleItemRowHolder;
}

    @Override
    public void onBindViewHolder(SingleItemRowHolder holder, int position) {
    SingleItemModel itemModel = itemModels.get(position);
    holder.tvTitle.setText(itemModel.getName());
}

    @Override
    public int getItemCount() {
    return (null != itemModels ? itemModels.size() : 0);
}

    public class SingleItemRowHolder extends RecyclerView.ViewHolder {

    protected TextView tvTitle;
    protected ImageButton itemImage;

        public SingleItemRowHolder(View itemView) {
            super(itemView);
            this.tvTitle = itemView.findViewById(R.id.tvTitle);
            this.itemImage = itemView.findViewById(R.id.itemImage);
            itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                    Toast.makeText(view.getContext(), tvTitle.getText(), Toast.LENGTH_SHORT).show();
                }
            });
        }
    }

}

公共类RecyclerViewDataAdapter扩展了RecyclerView.Adapter {

private ArrayList<SectionDataModel> dataList;
private Context mContext;
private RecyclerView.RecycledViewPool recycledViewPool;

public RecyclerViewDataAdapter(ArrayList<SectionDataModel> dataList, Context mContext) {
    this.dataList = dataList;
    this.mContext = mContext;
    recycledViewPool = new RecyclerView.RecycledViewPool();
}

@Override
public ItemRowHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item, null);
    ItemRowHolder rowHolder = new ItemRowHolder(v);
    return rowHolder;
}

@Override
public void onBindViewHolder(ItemRowHolder holder, int position) {
    final String sectionName = dataList.get(position).getHeaderTitle();
    ArrayList singleSectionItems = dataList.get(position).getAllItemInSection();
    holder.itemTitle.setText(sectionName);
    SectionListDataAdapter adapter = new SectionListDataAdapter(singleSectionItems, mContext);
    holder.recyclerView.setHasFixedSize(true);
    holder.recyclerView.setLayoutManager(new LinearLayoutManager(mContext, LinearLayoutManager.HORIZONTAL, false));
    holder.recyclerView.setAdapter(adapter);
    holder.recyclerView.setRecycledViewPool(recycledViewPool);

}

@Override
public int getItemCount() {
    return (null != dataList ? dataList.size() : 0);
}

public class ItemRowHolder extends RecyclerView.ViewHolder {
    protected TextView itemTitle;
    protected RecyclerView recyclerView;

    public ItemRowHolder(View itemView) {
        super(itemView);
        this.itemTitle = itemView.findViewById(R.id.itemTitle);
        this.recyclerView = itemView.findViewById(R.id.recycler_view_list);
    }
}

}

我希望能够从Firebase接收数据并将其存储在recyclerviews中。