Java 从云Firestore Android检索复杂对象

我试图从

云Firestore

数据库中检索一组复杂对象。这是我的班级：

public class Book {
    private String id;
    private String name;
    private String original;
    private ArrayList<Author> authors;
    private ArrayList<Translator> translators;
    private Series series;
    private Float no;
    private String seriesNo;
    private Integer published;
    private Borrower borrower;
    private Boolean isCollection;
    private Status status;
}

从数据库检索保存的值的最佳方法是什么？很难找到一种同时访问所有值的好方法。我目前使用以下方法检索作者和翻译人员（ArrayList）的值除外

public void getBooks（final BookRetrievable BookRetrievable，String userId）{
FirebaseFirestore=FirebaseFirestore.getInstance（）；
ArrayList books=新建ArrayList（）；
firebaseFirestore.收藏（“书籍”）
.get（）
.addOnCompleteListener（新的OnCompleteListener（）{
@凌驾
未完成的公共void（@NonNull任务）{
if（task.issusccessful（））{
对于（DocumentSnapshot DocumentSnapshot:task.getResult（））{
书=新书（）；
book.setId（documentSnapshot.getString（“id”）；
book.setName（documentSnapshot.getString（“名称”））；
book.setOriginal（documentSnapshot.getString（“original”）；
系列=新系列（）；
setId（documentSnapshot.getString（“series.id”）；
series.setName（documentSnapshot.getString（“series.name”）；
丛书（系列）；
book.setNo（documentSnapshot.getDouble（“no”）.floatValue（）；
book.setSeriesNo（documentSnapshot.getString（“seriesNo”）；
book.setPublished（documentSnapshot.getLong（“published”）.intValue（））；
借款人=新借款人（）；
setId（documentSnapshot.getString（“series.id”）；
follower.setNameInEnglish（documentSnapshot.getString（“series.nameInEnglish”）；
借款人.setNameInSinhalese（documentSnapshot.getString（“series.nameinsinsinhalese”）；
setFacebook（documentSnapshot.getString（“series.facebook”）；
setMobile（documentSnapshot.getString（“series.mobile”）；
帐面收款人（借款人）；
book.setIsCollection（documentSnapshot.getBoolean（“isCollection”）；
book.setStatus（Status.valueOf（documentSnapshot.getString（“Status”））；
图书。添加（图书）；
}
books.sort（（bookb1，bookb2）->b1.getName（）.compareTo（b2.getName（））；
可检索书籍。一次性回拨（书籍）；
}否则{
}
}
});
}

有什么比这更好的方法吗？请告诉我一次检索ArrayList的最佳方法是什么

为了便于理解，我添加了一个已保存在数据库中的示例的屏幕截图：

提前谢谢

将此Book对象保存到数据库的最佳方式是什么

将数据添加到数据中的方式没有错误。没有最好的办法。最好的解决方案是适合您的需要并使您的工作更轻松的解决方案。如果您在使用

地图时感到舒适，请让代码保持原样。如果您需要另一种方法，我可以为您提供另一种解决方案，即使用模型（POJO）类。这就是你的
书籍
课程的样子：

public class Book {
    private String id;
    private String name;
    private String original;
    private ArrayList<Author> authors;
    private ArrayList<Translator> translators;
    private Series series;
    private Float no;
    private String seriesNo;
    private Integer published;
    private Borrower borrower;
    private Boolean isCollection;
    private Status status;

    public Book() {}

    public Book(String id, String name, String original, ArrayList<Author> authors, ArrayList<Translator> translators, Series series, Float no, String seriesNo, Integer published, Borrower borrower, Boolean isCollection, Status status) {
        this.id = id;
        this.name = name;
        this.original = original;
        this.authors = authors;
        this.translators = translators;
        this.series = series;
        this.no = no;
        this.seriesNo = seriesNo;
        this.published = published;
        this.borrower = borrower;
        this.isCollection = isCollection;
        this.status = status;
    }

    public String getId() { return id; }
    public String getName() { return name; }
    public String getOriginal() { return original; }
    public ArrayList<Author> getAuthors() { return authors; }
    public ArrayList<Translator> getTranslators() { return translators; }
    public Series getSeries() { return series; }
    public Float getNo() { return no; }
    public String getSeriesNo() { return seriesNo; }
    public Integer getPublished() { return published; }
    public Borrower getBorrower() { return borrower; }
    public Boolean getCollection() { return isCollection; }
    public Status getStatus() { return status; }
}

公共课堂教材{
私有字符串id；
私有字符串名称；
私人字符串原件；
private ArrayList更多详细信息。
感谢您的评论。我非常了解异步行为，需要澄清我所做的是否错误，以及是否有更好、更简单的方法。我通过另一次回拨检索了我的子收集数据，现在一切似乎都失败了地点：）
public void getBooks(final BookRetrievable bookRetrievable, String userId) {
    FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
    ArrayList<Book> books = new ArrayList<>();

    firebaseFirestore.collection("books")
            .get()
            .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
                @Override
                public void onComplete(@NonNull Task<QuerySnapshot> task) {
                    if (task.isSuccessful()) {
                        for (DocumentSnapshot documentSnapshot : task.getResult()) {
                            Book book = new Book();
                            book.setId(documentSnapshot.getString("id"));
                            book.setName(documentSnapshot.getString("name"));
                            book.setOriginal(documentSnapshot.getString("original"));
                            Series series = new Series();
                            series.setId(documentSnapshot.getString("series.id"));
                            series.setName(documentSnapshot.getString("series.name"));
                            book.setSeries(series);
                            book.setNo(documentSnapshot.getDouble("no").floatValue());
                            book.setSeriesNo(documentSnapshot.getString("seriesNo"));
                            book.setPublished(documentSnapshot.getLong("published").intValue());
                            Borrower borrower = new Borrower();
                            borrower.setId(documentSnapshot.getString("series.id"));
                            borrower.setNameInEnglish(documentSnapshot.getString("series.nameInEnglish"));
                            borrower.setNameInSinhalese(documentSnapshot.getString("series.nameInSinhalese"));
                            borrower.setFacebook(documentSnapshot.getString("series.facebook"));
                            borrower.setMobile(documentSnapshot.getString("series.mobile"));
                            book.setBorrower(borrower);
                            book.setIsCollection(documentSnapshot.getBoolean("isCollection"));
                            book.setStatus(Status.valueOf(documentSnapshot.getString("status")));

                            books.add(book);
                        }

                        books.sort((Book b1, Book b2) -> b1.getName().compareTo(b2.getName()));
                        bookRetrievable.onCallback(books);
                    } else {
                    }
                }
            });
}

public class Book {
    private String id;
    private String name;
    private String original;
    private ArrayList<Author> authors;
    private ArrayList<Translator> translators;
    private Series series;
    private Float no;
    private String seriesNo;
    private Integer published;
    private Borrower borrower;
    private Boolean isCollection;
    private Status status;

    public Book() {}

    public Book(String id, String name, String original, ArrayList<Author> authors, ArrayList<Translator> translators, Series series, Float no, String seriesNo, Integer published, Borrower borrower, Boolean isCollection, Status status) {
        this.id = id;
        this.name = name;
        this.original = original;
        this.authors = authors;
        this.translators = translators;
        this.series = series;
        this.no = no;
        this.seriesNo = seriesNo;
        this.published = published;
        this.borrower = borrower;
        this.isCollection = isCollection;
        this.status = status;
    }

    public String getId() { return id; }
    public String getName() { return name; }
    public String getOriginal() { return original; }
    public ArrayList<Author> getAuthors() { return authors; }
    public ArrayList<Translator> getTranslators() { return translators; }
    public Series getSeries() { return series; }
    public Float getNo() { return no; }
    public String getSeriesNo() { return seriesNo; }
    public Integer getPublished() { return published; }
    public Borrower getBorrower() { return borrower; }
    public Boolean getCollection() { return isCollection; }
    public Status getStatus() { return status; }
}