Question

我制作了一个测试应用，试图找出Firestore数据库和RecyclerAdapter的功能。我按照了一些关于这个主题的教程，但我得到的最接近的是这个，当应用程序加载时，它可以看到数据库对象，因为它加载了正确的数字，当我这样做时有3个存储。但是当我设置句柄文本时，它会给我一个空字符串。

public class MainActivity extends AppCompatActivity {

FirebaseFirestore mDatabase;
private FirestoreRecyclerAdapter mFirestoreRecyclerAdapter;
RecyclerView mRecyclerView;
LinearLayoutManager mLayoutManager;
Toolbar mToolbar;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    init();
    initRecyclerAdapter();
    setSupportActionBar(mToolbar);
    FloatingActionButton fab = findViewById(R.id.fab);

    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });
}

@Override
public void onStart() {
    super.onStart();
    mFirestoreRecyclerAdapter.startListening();
}

@Override
public void onStop() {
    super.onStop();
    mFirestoreRecyclerAdapter.stopListening();
}
public void init() {
    mToolbar = findViewById(R.id.toolbar);
    mRecyclerView = findViewById(R.id.recycler_view);
    mLayoutManager = new LinearLayoutManager(getApplicationContext(), 
LinearLayoutManager.VERTICAL, false);
    mRecyclerView.setLayoutManager(mLayoutManager);
    mDatabase = FirebaseFirestore.getInstance();
}

private void initRecyclerAdapter() {
    Query query = mDatabase.collection("users");

    FirestoreRecyclerOptions<User> response = new 
FirestoreRecyclerOptions.Builder<User>()
            .setQuery(query, User.class)
            .build();

    mFirestoreRecyclerAdapter = new FirestoreRecyclerAdapter<User, 
MainActivity.UserHolder>(response) {
        @Override
        public MainActivity.UserHolder onCreateViewHolder(ViewGroup 
parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.list_item, parent, false);

            return new UserHolder(view);            }

        @Override
        protected void onBindViewHolder(MainActivity.UserHolder holder, 
int position, User model) {
            holder.setFirstName(model.getFirstName());
            holder.setLastName(model.getLastName());
            holder.setBornDate(model.getBornDate());
        }
    };
    mFirestoreRecyclerAdapter.notifyDataSetChanged();
    mRecyclerView.setAdapter(mFirestoreRecyclerAdapter);

}
public class UserHolder extends RecyclerView.ViewHolder {
    TextView textName;
    CircleImageView imageView;
    TextView textTitle;
    TextView textCompany;
    public View itemView;

    public UserHolder(View itemView) {
        super(itemView);
        textName = itemView.findViewById(R.id.name);
        textTitle = itemView.findViewById(R.id.title);
        textCompany = itemView.findViewById(R.id.company);
        this.itemView = itemView;
    }
    public void setFirstName(String name) {
        textName.setText(name);
    }
    public void setLastName(String lastName) {
        textTitle.setText(lastName);
    }
    public void setBornDate(String bornDate) {
        textCompany.setText(bornDate);
    }
}
}

public class User {

private String born;
private String first;
private String last;

public User() { }

public User(String born, String first, String last) {
    this.born = born;
    this.first = first;
    this.last = last;
}

public String getFirstName() {
    return first;
}

public void setFirstName(String first) {
    this.first = first;
}

public String getLastName() {
    return last;
}

public void setLastName(String last) {
    this.last = last;
}

public String getBornDate() {
    return born;
}

public void setBornDate(String born) {
    this.born = born;
}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

dependencies {

    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:27.0.2'
    implementation 'com.android.support:design:27.0.2'
    implementation 'com.android.support:cardview-v7:27.0.2'
    implementation 'com.android.support:recyclerview-v7:27.0.2'

    implementation 'de.hdodenhof:circleimageview:2.0.0'

    implementation 'com.google.firebase:firebase-core:11.4.2'
    implementation 'com.google.firebase:firebase-firestore:11.4.2'
    implementation 'com.firebaseui:firebase-ui-firestore:3.0.0'

    implementation 'com.android.support.constraint:constraint- 
    layout:1.1.2'
    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'
}
apply plugin: 'com.google.gms.google-services'

截图

Answer 1

代码中的问题是您的所有字段都有错误的getter。因此，像born这样的字段应该具有getBorn()方法作为getter而不是getBornDate()。对于first和last，正确的获取者为getFirst()和getLast()，而不是getFirstName()和getLastName()，因为它现在位于您的代码中。请参阅下面的模型类应该如何：

public class User {
    private String born;
    private String first;
    private String last;

    public User() { }

    public User(String born, String first, String last) {
        this.born = born;
        this.first = first;
        this.last = last;
    }

    public String getBorn() { return born; }
    public void setBorn(String born) { this.born = born; }

    public String getFirst() { return first; }
    public void setFirst(String first) { this.first = first; }

    public String getLast() { return last; }
    public void setLast(String last) { this.last = last; }
}

其余代码是正确的。

Firestore在填充时使文本字段为空

1 个答案: