当从 FirestoreRecyclerAdapter 调用时，为什么某些 Firestore 文档值为 null？ （在课堂上找不到...的设置器/字段）

Question

我有一个 Firestore 购买集合，其中包含 companyId、storeId、value、timestamp 和 purchaseId 的文档值。我试图在 FirestoreRecyclerAdapter 中调用这些以显示收据列表。

我的问题是一些文档值（companyId、storId、purchaseId）返回空值，而一些（时间戳、值）根据需要返回值。

日志说，对于这些返回 null 的值，在类 Receipt 上没有设置器/字段。我一直试图在 Stackexchange 上找到答案，但找不到相关的答案。我发现的最接近的是在类 Receipt 中启动值的类类型与数据库中的类型不匹配，但我仔细检查了它们在这两种情况下都是字符串。

对此的任何帮助将不胜感激！

这是 Firestore 结构：

我有一个 Receipt 类：

import com.google.firebase.Timestamp;

public class Receipt {
    private String companyId, purchaseId, storeId, value;
    Timestamp timestamp;

    public Receipt() {
    }

    public Receipt(String companyId, String purchaseId, String storeId, Timestamp timestamp, String value) {
        this.companyId = companyId;
        this.purchaseId = purchaseId;
        this.storeId = storeId;
        this.timestamp = timestamp;
        this.value = value;
    }

    public String getCompany() {
        return companyId;
    }

    public void setCompany(String companyId) {
        this.companyId = companyId;
    }

    public String getPurchase() {
        return purchaseId;
    }

    public void setPurchase(String purchaseId) {
        this.purchaseId = purchaseId;
    }

    public String getStore() {
        return storeId;
    }

    public void setStore(String storeId) {
        this.storeId = storeId;
    }

    public Timestamp getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(Timestamp timestamp) {
        this.timestamp = timestamp;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

}

有一个DisplayReceiptsViewHolder：

import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;

import androidx.recyclerview.widget.RecyclerView;

import com.dummies.rbncr.tapaidhscanner4.R;

public class DisplayReceiptsViewHolder extends RecyclerView.ViewHolder implements 
View.OnClickListener {
    public TextView date, company, amount;
    public Button viewReceiptButton;
    private AdapterView.OnItemClickListener itemClickListener;

    public DisplayReceiptsViewHolder(View itemView){
        super(itemView);
        date = itemView.findViewById(R.id.receipt_list_date_tv);
        company = itemView.findViewById(R.id.receipt_list_company_tv);
        amount = itemView.findViewById(R.id.receipt_list_amount_tv);
        viewReceiptButton = itemView.findViewById(R.id.view_receipt_list_btn);
    }
    @Override
    public void onClick(View v) {
        //itemClickListener.onItemClick(v, v, getAdapterPosition(), false);
    }

    public void setItemClickListener(AdapterView.OnItemClickListener itemClickListener) {
        this.itemClickListener = itemClickListener;
    }
}

然后在 DisplayReceiptsActivity 中，我现在只是检索值并将它们记录到控制台：

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.dummies.rbncr.tapaidhscanner4.Models.Receipt;
import com.dummies.rbncr.tapaidhscanner4.ViewHolders.DisplayReceiptsViewHolder;
import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.firebase.Timestamp;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;


public class DisplayReceiptsActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    FirestoreRecyclerAdapter<Receipt, DisplayReceiptsViewHolder> receiptAdapter;

    FirebaseFirestore db = FirebaseFirestore.getInstance();
    FirebaseUser currentUser = FirebaseAuth.getInstance().getCurrentUser();

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

        recyclerView = findViewById(R.id.display_receipt_list);

        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);

        Query receiptsQuery = FirebaseFirestore.getInstance()
                .collection("Users")
                .document(currentUser.getUid())
                .collection("Purchases");

        FirestoreRecyclerOptions<Receipt> receiptOptions = new FirestoreRecyclerOptions.Builder<Receipt>()
                .setQuery(receiptsQuery, Receipt.class)
                .build();

        receiptAdapter = new FirestoreRecyclerAdapter<Receipt, DisplayReceiptsViewHolder>(receiptOptions) {
            @SuppressLint("SetTextI18n")
            @Override
            protected void onBindViewHolder(@NonNull DisplayReceiptsViewHolder displayReceiptsViewHolder,
                                        int i,
                                        @NonNull Receipt receipt) {

                String company = receipt.getCompany();
                displayReceiptsViewHolder.company.setText(company);
                Log.d("TESTING", "Company = " + company);

                String purchaseId = receipt.getPurchase();
                Log.d("TESTING", "Purchase = " + purchaseId);

                String storeId = receipt.getStore();
                Log.d("TESTING", "Store = " + storeId);

                Timestamp timestamp = receipt.getTimestamp();
                displayReceiptsViewHolder.date.setText(timestamp.toString());
                Log.d("TESTING", "Timestamp = " + timestamp);

                String value = receipt.getValue();
                displayReceiptsViewHolder.amount.setText(value);
                Log.d("TESTING", "Value = " + value);
            }

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

    @Override
    protected void onStart() {
        super.onStart();
        recyclerView.setAdapter(receiptAdapter);
        receiptAdapter.startListening();
    }

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

    public void returnHome(View view) {
        Intent intent = new Intent(DisplayReceiptsActivity.this, ShopHomeActivity.class);
        startActivity(intent);
    }

    @Override
    public void onBackPressed(){
        Intent intent = new Intent(DisplayReceiptsActivity.this, ShopHomeActivity.class);
        startActivity(intent);
    }

}

这是日志的副本：

2021-12-23 15:48:56.330 2462-2462/com.dummies.rbncr.tapaidhscanner4 W/Firestore: (24.0.0) [CustomClassMapper]: No setter/field for companyId found on class com.dummies.rbncr.tapaidhscanner4.Models.Receipt
2021-12-23 15:48:56.330 2462-2462/com.dummies.rbncr.tapaidhscanner4 W/Firestore: (24.0.0) [CustomClassMapper]: No setter/field for purchaseId found on class com.dummies.rbncr.tapaidhscanner4.Models.Receipt
2021-12-23 15:48:56.330 2462-2462/com.dummies.rbncr.tapaidhscanner4 W/Firestore: (24.0.0) [CustomClassMapper]: No setter/field for storeId found on class com.dummies.rbncr.tapaidhscanner4.Models.Receipt
2021-12-23 15:48:56.331 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Company = null
2021-12-23 15:48:56.331 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Purchase = null
2021-12-23 15:48:56.331 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Store = null
2021-12-23 15:48:56.332 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Timestamp = Timestamp(seconds=1640270467, nanoseconds=629000000)
2021-12-23 15:48:56.332 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Value = 0.75
2021-12-23 15:48:56.358 2462-2462/com.dummies.rbncr.tapaidhscanner4 W/Firestore: (24.0.0) [CustomClassMapper]: No setter/field for companyId found on class com.dummies.rbncr.tapaidhscanner4.Models.Receipt
2021-12-23 15:48:56.358 2462-2462/com.dummies.rbncr.tapaidhscanner4 W/Firestore: (24.0.0) [CustomClassMapper]: No setter/field for purchaseId found on class com.dummies.rbncr.tapaidhscanner4.Models.Receipt
2021-12-23 15:48:56.359 2462-2462/com.dummies.rbncr.tapaidhscanner4 W/Firestore: (24.0.0) [CustomClassMapper]: No setter/field for storeId found on class com.dummies.rbncr.tapaidhscanner4.Models.Receipt
2021-12-23 15:48:56.359 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Company = null
2021-12-23 15:48:56.360 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Purchase = null
2021-12-23 15:48:56.360 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Store = null
2021-12-23 15:48:56.360 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Timestamp = Timestamp(seconds=1640273317, nanoseconds=835000000)
2021-12-23 15:48:56.360 2462-2462/com.dummies.rbncr.tapaidhscanner4 D/TESTING: Value = 0.75

Answer 1

好的 - 所以我通过将 Receipt 类中的 getter 和 setter 的名称编辑为与变量名称相同来解决了这个问题。我不确定为什么会这样，但确实有效：

import com.google.firebase.Timestamp;

public class Receipt {
    private String companyId, purchaseId, storeId, value;
    Timestamp timestamp;

    public Receipt() {
    }

    public Receipt(String companyId, String purchaseId, String storeId, Timestamp timestamp, String value) {
        this.companyId = companyId;
        this.purchaseId = purchaseId;
        this.storeId = storeId;
        this.timestamp = timestamp;
        this.value = value;
    }
    
    // updated from getCompany()
    public String getCompanyId() {
        return companyId;
    }
    
    // updated from setCompany(String companyId)
    public void setCompanyId(String companyId) {
        this.companyId = companyId;
    }

    // updated from getPurchase()
    public String getPurchaseId() {
        return purchaseId;
    }

    // updated from setPurchase(String purchaseId)
    public void setPurchaseId(String purchaseId) {
        this.purchaseId = purchaseId;
    }

    // updated from setStore()
    public String getStoreId() {
        return storeId;
    }

    // updated from setStore(String storeId)
    public void setStoreId(String storeId) {
        this.storeId = storeId;
    }

    public Timestamp getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(Timestamp timestamp) {
        this.timestamp = timestamp;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

}