CardView不显示任何数据

Question

我已经实现了cardview来显示firebase数据库中的数据。我正在按照this这个项目的教程进行操作。我几乎按照指示进行了所有操作，但是仍然没有显示任何数据。

我的数据库结构是

Notebook
 |-0
  |-description
  |-priority
  |-title
|-1
  |-description
  |-priority
  |-title

主类（多米诺骨牌）

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

import com.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.firebase.firestore.CollectionReference;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;

public class minos extends AppCompatActivity {
    private FirebaseFirestore db = FirebaseFirestore.getInstance();
    private CollectionReference notebookRef = db.collection("Notebook");

    private NoteAdapter adapter;

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

        setUpRecyclerView();
    }

    private void setUpRecyclerView() {
        Query query = notebookRef.orderBy("priority", Query.Direction.DESCENDING);

        FirestoreRecyclerOptions<Note> options = new FirestoreRecyclerOptions.Builder<Note>()
                .setQuery(query, Note.class)
                .build();

        adapter = new NoteAdapter(options);

        RecyclerView recyclerView = findViewById(R.id.myrecycler);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);
    }

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

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

我也曾尝试将wrap_content用于RecyclerView的活动minos，但无法正常工作。

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/myrecycler"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/holo_green_dark"/>

</RelativeLayout>

CardView（note_item）

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:cardBackgroundColor="#FFFFE8">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="8dp">

        <TextView
            android:id="@+id/text_view_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_toLeftOf="@id/text_view_priority"
            android:ellipsize="end"
            android:maxLines="1"
            android:text="Title"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />

        <TextView
            android:id="@+id/text_view_priority"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:text="1"
            android:textAppearance="@style/TextAppearance.AppCompat.Large" />

        <TextView
            android:id="@+id/text_view_description"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_below="@id/text_view_title"
            android:text="Description" />

    </RelativeLayout>

</android.support.v7.widget.CardView>

NoteAdapter

import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;

public class NoteAdapter extends FirestoreRecyclerAdapter<Note, NoteAdapter.NoteHolder> {

    public NoteAdapter(@NonNull FirestoreRecyclerOptions<Note> options) {
        super(options);
    }

    @Override
    protected void onBindViewHolder(@NonNull NoteHolder holder, int position, @NonNull Note model) {
        holder.textViewTitle.setText(model.getTitle());
        holder.textViewDescription.setText(model.getDescription());
        holder.textViewPriority.setText(String.valueOf(model.getPriority()));
    }

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

    class NoteHolder extends RecyclerView.ViewHolder {
        TextView textViewTitle;
        TextView textViewDescription;
        TextView textViewPriority;

        public NoteHolder(View itemView) {
            super(itemView);
            textViewTitle = itemView.findViewById(R.id.text_view_title);
            textViewDescription = itemView.findViewById(R.id.text_view_description);
            textViewPriority = itemView.findViewById(R.id.text_view_priority);
        }
    }
}

注意Java

public class Note {
    private String title;
    private String description;
    private int priority;

    public Note() {
        //empty constructor needed
    }

    public Note(String title, String description, int priority) {
        this.title = title;
        this.description = description;
        this.priority = priority;
    }

    public String getTitle() {
        return title;
    }

    public String getDescription() {
        return description;
    }

    public int getPriority() {
        return priority;
    }
}

Gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    lintOptions {

        checkReleaseBuilds false


    }
    defaultConfig {
        applicationId "com.samin.world"
        minSdkVersion 16
        targetSdkVersion 27
        versionCode 13
        versionName '1.0'
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    //noinspection GradleCompatible
    implementation 'com.android.support:appcompat-v7:27.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.0'
    implementation 'com.google.firebase:firebase-core:15.0.2'
    implementation 'com.anjlab.android.iab.v3:library:1.0.44'
    implementation 'com.google.firebase:firebase-auth:15.0.0'
    implementation 'com.google.firebase:firebase-database:15.0.0'
    implementation 'com.google.android.gms:play-services-ads:15.0.0'
    implementation 'com.google.android.gms:play-services-auth:15.0.0'
    implementation 'com.google.firebase:firebase-messaging:15.0.2'
    implementation 'com.facebook.android:facebook-android-sdk:[4,5)'
    implementation 'com.github.florent37:materialtextfield:1.0.7'
    implementation 'pl.droidsonroids.gif:android-gif-drawable:1.2.15'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'com.android.support:design:27.1.0'
    implementation 'com.android.support:cardview-v7:27.1.0'
    implementation 'com.android.support:customtabs:27.1.0'
    implementation 'com.android.support:support-v4:27.1.0'
    implementation 'com.android.support:recyclerview-v7:27.1.0'
    implementation 'com.firebaseui:firebase-ui-firestore:4.1.0'
    implementation 'android.arch.core:runtime:1.1.1'


}
apply plugin: 'com.google.gms.google-services'