Question

基本上，这是我在Firestore中的数据模型：集合>文档>包含地图数组>包含数组的地图>包含地图的数组

我能够读取和显示这些地图及其值，并且我学会了如何更新单个地图的值，但不能更新如下所示的地图数组：https://firebase.google.com/docs/firestore/manage-data/add-data#update_fields_in_nested_objects

应用逻辑是这样的：用户将获得程序（文档）列表，单击将要求输入学期，输入学期后，将加载该特定学期的论文列表，现在用户将选择特定论文，然后加载该论文。 TotalDays 和该论文中的学生列表及其 ID 和 DaysPresent 。

但是，我正试图找到一种方法来更新多个对象（又称地图）的字段。具体来说，我正在尝试为每个纸质地图和每个学生地图的 DaysPresent 更新 DaysTotal 。

我使用RecyclerView来显示数据。

纸张模型类：

public final class Paper {
private String name;
private String courseCode;
private Long totalDays;
private List<Student> studentList;

public Paper(String name, String courseCode, Long totalDays) {
    this.name = name;
    this.courseCode = courseCode;
    this.totalDays = totalDays;
}

public void setTotalDays(Long totalDays) {
    this.totalDays = totalDays;
}

public void setStudentList(@NonNull List<Student> studentList) {
    this.studentList = studentList;
}

public String getName() {
    return name;
}

public String getCourseCode() {
    return courseCode;
}

public Long getTotalDays() {
    return totalDays;
}

public List<Student> getStudentList() {
    return studentList;
}
}

学生模型类：

public final class Student {
private String studentId;
private Long daysPresent = 0L;

public Student(String studentId, Long daysPresent) {
    this.studentId = studentId;
    this.daysPresent = daysPresent;
}

public void setDaysPresent(Long daysPresent) {
    this.daysPresent = daysPresent;
}

public String getStudentId() {
    return studentId;
}

public Long getDaysPresent() {
    return daysPresent;
}
}

我显示DaysTotal，ID和出现的天数并需要实现更新方法的代码：

public class EditAttendance2 extends AppCompatActivity implements StudentAdapter.OnItemClickListener {
private static final String TAG = EditAttendance2.class.getSimpleName();

private RecyclerView recyclerView;

Long semesterValue;
Integer paperID;
public String Dept;
private EditText total;

private List<Paper> paperList;
//private List<Student> studentList;
private StudentAdapter studentAdapter;

private boolean activeDbCall;
private FirebaseFirestore db = FirebaseFirestore.getInstance();
String documentID;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_edit_attendance2);
    recyclerView = findViewById(R.id.student_recyclerview);
    recyclerView.setLayoutManager(new LinearLayoutManager(EditAttendance2.this));
    total = findViewById(R.id.totalEdit);

    Bundle extras = getIntent().getExtras();
    if (extras != null) {
        paperID = extras.getInt(EditAttendance.PAPER_POS);
        semesterValue = extras.getLong(EditAttendance.SEMESTER_ID);
        documentID = extras.getString(EditAttendance.DOCUMENT_ID);
        //Log.d(TAG, documentID);
    }
    Dept = PrefUtilities.with(this).getDepartment();
    Display();
}

public void Display() {
    if (!activeDbCall) {
        activeDbCall = true;
        final CollectionReference Department = db.collection(Dept);
        final DocumentReference dbDocs = Department.document(documentID);
        dbDocs.addSnapshotListener(this, new EventListener<DocumentSnapshot>() {
            @Override
            public void onEvent(@Nullable DocumentSnapshot documentSnapshot, @Nullable FirebaseFirestoreException e) {
                if (documentSnapshot != null) {
                    Map<String, Object> data = documentSnapshot.getData();
                    if (data != null) {
                        Semesters semesters = new Semesters(data);
                        paperList = semesters.getPaperList(semesterValue);
                        Paper paper =paperList.get(paperID);
                        Long totalDays = paper.getTotalDays();
                        Log.d(TAG,"****************************************************");
                        Log.d(TAG,"Total Days: " + totalDays);
                        Log.d(TAG,"****************************************************");


                        List<Student> studentList = paper.getStudentList();
                        total.setText(totalDays.toString());
                        studentAdapter = new StudentAdapter(studentList);
                        studentAdapter.setOnItemClickListener(EditAttendance2.this);
                        recyclerView.setAdapter(studentAdapter);
                    }
                }

            }
        });
    }
}

@Override
public void onItemClick(int position) {

}

@Override
public void onUpdateClick(int position) {

}

@Override
public void onDeleteClick(int position) {

}
}

如何一次性更新Android（Firestore）中多个嵌套对象中的字段？

0 个答案: