Firebase 数据库的某些数据未在 recyclerview 中显示答案

【问题标题】：Some data of Firebase databse is not displayed in recyclerviewFirebase 数据库的某些数据未在 recyclerview 中显示
【发布时间】：2022-01-26 00:17:38
【问题描述】：

我创建了一个应用程序并将一些数据存储在 firebase 数据库中。我想在 recyclerview 中显示数据，但未填充所有数据，即显示 4 个字段的数据，但 recyclerview 未显示两个字段（血组和电话号码）的数据。下面是我的代码。提前致谢

我的适配器RcvAdapter

public class RcvAdapter extends FirebaseRecyclerAdapter<ModelClass, RcvAdapter.MyViewHolder> {

    public RcvAdapter(@NonNull @NotNull FirebaseRecyclerOptions<ModelClass> options) {
        super(options);
    }

    @Override
    protected void onBindViewHolder(@NonNull @NotNull MyViewHolder holder, int position, @NonNull @NotNull ModelClass model) {

        holder.uAddress.setText(model.getAddress());
        holder.uBGroup.setText(model.getBloodGroup());
        holder.uCity.setText(model.getCity());
        holder.uDistrict.setText(model.getDistrict());
        holder.uName.setText(model.getName());
        holder.uPhone.setText(model.getPhoneNumber());
        holder.uContact.setText(model.getContact());
    }

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

    class MyViewHolder extends RecyclerView.ViewHolder{

        TextView uAddress;
        TextView uBGroup;
        TextView uCity;
        TextView uDistrict;
        TextView uName;
        TextView uPhone;
        TextView uContact;

        public MyViewHolder(@NonNull @NotNull View itemView) {
            super(itemView);

            uAddress = (TextView) itemView.findViewById(R.id.rcv_address);
            uBGroup =(TextView)  itemView.findViewById(R.id.rcv_bloodGroup);
            uCity =(TextView)  itemView.findViewById(R.id.rcv_city);
            uDistrict =(TextView)  itemView.findViewById(R.id.rcv_district);
            uName =(TextView)  itemView.findViewById(R.id.rcv_name);
            uPhone = (TextView) itemView.findViewById(R.id.rcv_phoneNumber);
            uContact =(TextView)  itemView.findViewById(R.id.rcv_contact);
        }
    }

Recyclerview 单行布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    app:cardCornerRadius="5dp"
    android:elevation="5dp"
    app:cardUseCompatPadding="true"
    android:layout_height="wrap_content">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/rcv_address"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_light"
            android:text="Lal colony"
            android:textAlignment="center"
            android:textColor="#070707"
            android:textSize="16sp"

            app:layout_constraintEnd_toEndOf="@+id/rcv_phoneNumber"
            app:layout_constraintHorizontal_bias="0.0"
            app:layout_constraintStart_toStartOf="@+id/rcv_phoneNumber"
            app:layout_constraintTop_toBottomOf="@+id/rcv_phoneNumber" />

        <TextView
            android:id="@+id/rcv_district"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_light"
            android:text="Malakand"
            android:textAlignment="center"
            android:textColor="#070707"
            android:textSize="16sp"

            app:layout_constraintEnd_toEndOf="@+id/rcv_city"
            app:layout_constraintStart_toStartOf="@+id/rcv_city"
            app:layout_constraintTop_toBottomOf="@+id/rcv_city" />

        <TextView
            android:id="@+id/rcv_city"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_light"
            android:text="Thana"
            android:textAlignment="center"
            android:textColor="#070707"
            android:textSize="16sp"

            app:layout_constraintEnd_toEndOf="@+id/rcv_address"
            app:layout_constraintStart_toStartOf="@+id/rcv_address"
            app:layout_constraintTop_toBottomOf="@+id/rcv_address" />

        <TextView
            android:id="@+id/textView6"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_medium"
            android:text="Address"
            android:textColor="#070707"
            android:textSize="16sp"

            app:layout_constraintEnd_toEndOf="@+id/textView3"
            app:layout_constraintStart_toStartOf="@+id/textView3"
            app:layout_constraintTop_toBottomOf="@+id/textView3" />

        <TextView
            android:id="@+id/textView9"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_medium"
            android:text="City"
            android:textColor="#070707"
            android:textSize="16sp"

            app:layout_constraintEnd_toEndOf="@+id/textView6"
            app:layout_constraintStart_toStartOf="@+id/textView6"
            app:layout_constraintTop_toBottomOf="@+id/textView6" />

        <TextView
            android:id="@+id/textView7"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_medium"
            android:text="District"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="@+id/textView9"
            app:layout_constraintStart_toStartOf="@+id/textView9"
            app:layout_constraintTop_toBottomOf="@+id/textView9"
        />

        <TextView
            android:id="@+id/rcv_name"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginStart="50dp"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_light"
            android:text="User Name"
            android:textAlignment="center"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toEndOf="@+id/textView"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/rcv_bloodGroup"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginStart="32dp"
            android:layout_marginTop="8dp"
            android:layout_marginEnd="32dp"
            android:fontFamily="@font/roboto_light"
            android:text="Blood Group"
            android:textAlignment="center"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="@+id/rcv_name"
            app:layout_constraintStart_toStartOf="@+id/rcv_name"
            app:layout_constraintTop_toBottomOf="@+id/rcv_name" />

        <TextView
            android:id="@+id/rcv_phoneNumber"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_light"
            android:text="+923005658587"
            android:textAlignment="center"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="@+id/rcv_name"
            app:layout_constraintTop_toBottomOf="@+id/rcv_bloodGroup" />

        <TextView
            android:id="@+id/rcv_contact"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:fontFamily="sans-serif-medium"
            android:text="Contact"
            android:textAlignment="center"
            android:textColor="#2196F3"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/textView7" />

        <TextView
            android:id="@+id/textView"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginTop="8dp"
            android:layout_marginEnd="250dp"
            android:fontFamily="@font/roboto_medium"
            android:text="Name"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_medium"
            android:text="Blood Group"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="@+id/textView"
            app:layout_constraintStart_toStartOf="@+id/textView"
            app:layout_constraintTop_toBottomOf="@+id/textView" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:fontFamily="@font/roboto_medium"
            android:text="Phone No"
            android:textColor="#070707"
            android:textSize="16sp"
            app:layout_constraintEnd_toEndOf="@+id/textView2"
            app:layout_constraintStart_toStartOf="@+id/textView2"
            app:layout_constraintTop_toBottomOf="@+id/textView2" />

    </androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>

我的 MainActivity

public class DashboardActivity extends AppCompatActivity {
    RecyclerView recyclerView;
    RcvAdapter adapter;
   

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




        recyclerView = findViewById(R.id.recyclerView);
       
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
  //      database = FirebaseDatabase.getInstance().getReference().child("Users");

// Retrive firebase data into recyclerview
        FirebaseRecyclerOptions<ModelClass> options =
                new FirebaseRecyclerOptions.Builder<ModelClass>()
                        .setQuery(FirebaseDatabase.getInstance().getReference().child("Users"), ModelClass.class)
                        .build();

        adapter = new RcvAdapter(options);
        recyclerView.setAdapter(adapter);
    }
    @Override
    protected void onStart() {
        super.onStart();
        adapter.startListening();
    }

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

            adapter.stopListening();

    }

模型类

public class ModelClass {

    String address;
    String bloodGroup;
    String city;
    String district;
    String name;
    String phoneNumber;
    String contact;

    public ModelClass() {

    }

    public ModelClass(String address, String bloodGroup, String city, String district, String name, String phoneNumber, String contact) {
        this.address = address;
        this.bloodGroup = bloodGroup;
        this.city = city;
        this.district = district;
        this.name = name;
        this.phoneNumber = phoneNumber;
        this.contact = contact;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getBloodGroup() {
        return bloodGroup;
    }

    public void setBloodGroup(String bloodGroup) {
        this.bloodGroup = bloodGroup;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getDistrict() {
        return district;
    }

    public void setDistrict(String district) {
        this.district = district;
    }

    public String getName() {
        return name;
    }

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

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getContact() {
        return contact;
    }

    public void setContact(String contact) {
        this.contact = contact;
    }
    
}

血型和电话号码的数据没有填充。

DashboardActivity 布局

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/dark_red"
    tools:context=".DashboardActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

【问题讨论】：

乍一看，代码看起来不错，并且与数据结构相匹配，但很难一目了然地对其进行调试。我建议在onCreateViewHolder 和onBindViewHolder 中设置断点并在调试器中运行以查看它们是否被调用。如果没有，这意味着没有数据从数据库返回，我建议检查 logcat 输出是否有错误。
可能是视图被剪裁（在其他字段之间被挤压）。我注意到@id/rcv_contact 有一个android:layout_width="wrap_content"，而所有其他的都有一个android:layout_width="0dp"。这是故意的吗？另外，一般建议，我建议确保使用虚拟数据正确构建视图（取出 firebase 块并创建一个模拟模型），以确保视图/适配器独立于 firebase 块工作。
@FrankvanPuffelen logcat 中没有错误。
@sleepystar96 是的，这些是故意的，我什至使用了线性布局，但是只有两个字段的数据没有填充，而 4 个字段的数据正在填充。
@sleepystar96 问题已解决。将模型类的变量名称与 firebasedatabse 匹配解决了它。请发布它作为答案。谢谢

标签： android firebase-realtime-database android-recyclerview firebaseui

【解决方案1】：

由于您将默认编码器/解码器与 FirebaseRecycler 类一起使用，因此您应确保将数据库中的键名与模型中的键名匹配。

例如，尝试将ModelClass 中的“phoneNumber”更改为“phone”（与数据库相同）。

【讨论】：