在Android的RecyclerView中顯示Firebase中的數據

Question

我目前已經實現了RecyclerView，但是我的CarView不顯示數據。

這些是我當前在Firebase中的數據：

但是RecyclerView顯示了所有三個CardView，但是沒有記錄：

這些是我正在使用的文件：DomiciliarySearchFragment.java

import android.os.Bundle;
import android.os.AsyncTask;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.didierzuniga.domix.R;
import com.didierzuniga.domix.adapter.OrderAdapterRecyclerView;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.HashMap;

import butterknife.Bind;
import butterknife.ButterKnife;

/**
 * A simple {@link Fragment} subclass.
 */
public class DomiciliarySearchFragment extends Fragment {

    @Bind(R.id.recycler_order) RecyclerView recyclerView;

    public DomiciliarySearchFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        super.onCreate(savedInstanceState);
        View view = inflater.inflate(R.layout.fragment_domiciliary_search, container, false);
        showToolbar(getResources().getString(R.string.tab_search), true, view);
        ButterKnife.bind(this, view);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
        new GetDataFromFirebase().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

        // Read from the database
        FirebaseDatabase database = FirebaseDatabase.getInstance();
        DatabaseReference myRef = database.getReference("order");

        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                HashMap<String, String> values = (HashMap<String, String>) dataSnapshot.getValue();
                recyclerView.setAdapter(new OrderAdapterRecyclerView(values));
            }

            @Override
            public void onCancelled(DatabaseError error) {
                // Failed to read value
                System.out.println("Failed to read value." + error.toException());
            }
        });

        return view;
    }

    private class GetDataFromFirebase extends AsyncTask<Void,Void,Boolean>{

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected Boolean doInBackground(Void... voids) {
            return false;
        }

        @Override
        protected void onPostExecute(Boolean aBoolean) {
            super.onPostExecute(aBoolean);
        }
    }

    public void showToolbar(String tittle, boolean upButton, View view){
        Toolbar toolbar = (Toolbar) view.findViewById(R.id.toolbar);
        ((AppCompatActivity) getActivity()).setSupportActionBar(toolbar);
        ((AppCompatActivity) getActivity()).getSupportActionBar().setTitle(tittle);
        ((AppCompatActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(upButton);
    }
}

OrderAdapterRecyclerView.java

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.didierzuniga.domix.R;
import java.util.HashMap;
import java.util.Map;

public class OrderAdapterRecyclerView extends RecyclerView.Adapter<OrderAdapterRecyclerView.ViewHolder>{
    private HashMap<String, String> values;
    public OrderAdapterRecyclerView(HashMap<String, String> values) {
        this.values = values;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.cardview_order,parent,false));
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.fromm.setText(values.get(position));
        holder.too.setText(values.get(position));
        holder.moneyToPayy.setText(values.get(position));
    }

    @Override
    public int getItemCount() {
        return values.size();
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        private TextView fromm;
        private TextView too;
        private TextView moneyToPayy;
        ViewHolder(View itemView) {
            super(itemView);
            fromm = (TextView) itemView.findViewById(R.id.from);
            too = (TextView) itemView.findViewById(R.id.to);
            moneyToPayy = (TextView) itemView.findViewById(R.id.moneyToPay);
        }
    }
}

型號：Order.java

public class Order {
    public String uid;
    public String oFrom;
    public String oTo;
    public String oHeader;
    public String oDescription;
    public String oMoneyToPay;
    public String oAuthor;
    public boolean completed;

public Order(){

    }

public Order(String oFrom, String oTo, String oHeader, String oDescription, String oMoneyToPay, String oAuthor) {
    this.oFrom = oFrom;
    this.oTo = oTo;
    this.oHeader = oHeader;
    this.oDescription = oDescription;
    this.oMoneyToPay = oMoneyToPay;
    this.oAuthor = oAuthor;
    this.completed = false;
}

public String getUid() {
    return uid;
}

public void setUid(String uid) {
    this.uid = uid;
}

public String getoFrom() {
    return oFrom;
}

public void setoFrom(String oFrom) {
    this.oFrom = oFrom;
}

public String getoTo() {
    return oTo;
}

public void setoTo(String oTo) {
    this.oTo = oTo;
}

public String getoHeader() {
    return oHeader;
}

public void setoHeader(String oHeader) {
    this.oHeader = oHeader;
}

public String getoDescription() {
    return oDescription;
}

public void setoDescription(String oDescription) {
    this.oDescription = oDescription;
}

public String getoMoneyToPay() {
    return oMoneyToPay;
}

public void setoMoneyToPay(String oMoneyToPay) {
    this.oMoneyToPay = oMoneyToPay;
}

public String getoAuthor() {
    return oAuthor;
}

public void setoAuthor(String oAuthor) {
    this.oAuthor = oAuthor;
}

public boolean isCompleted() {
    return completed;
}

public void setCompleted(boolean completed) {
    this.completed = completed;
}
}

¿能做什么才能顯示每個CardView中的寄存器？

謝謝！

Answer 1

在DomiciliarySearchFragment.java / onDataChange中，您可以確認哈希圖已正確填充嗎？

我有一個類似的問題，但是原因是數據沒有正確存儲在集合中

Answer 2

謝謝uguboz，我應該使用dataSnapshot.getChildren（），並在循環中一一獲取所有記錄

        rv = (RecyclerView) view.findViewById(R.id.recycler_order);
        rv.setLayoutManager(new LinearLayoutManager(getContext()));
        orders = new ArrayList<>();
        FirebaseDatabase database = FirebaseDatabase.getInstance();
        adapter = new OrderAdapter(orders);
        rv.setAdapter(adapter);

        database.getReference().child("order").addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                orders.removeAll(orders);
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    Order order = snapshot.getValue(Order.class);
                    orders.add(order);
                }
                adapter.notifyDataSetChanged();
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

謝謝大家。