Question

我的会议室数据库中有3种方法

Flowable<List<Book>> getBooks() {....}
Flowable<List<Author>> getAuthors(int bookId) {....}
Flowable<List<Category>> getCategories(int bookId) {....}

Book对象

Book {int id; List<Author> authors; List<Category> categories}

我正在尝试做类似的事情

Flowable<List<Book>> getBookFullBooks() {
    return getBooks()
    //1. get the list of books from flowable??
    //2. get each book from the list??
    //3. set properties of each book from getAuthors(book.id) and 
    //   getCategories(book.id)
    // Something like:
        .switchMap(book -> _getCategories(book.id).map(categories -> {
            book.categories = categories;
            return book;
        }))
       .switchMap(book -> _getAuthors(book.id).map(authors -> {
           book.authors = authors;
           return book;
       }));// collect the books into a sequentioal Flowable<List<Book>>
}
//4. then return all the books as Flowable<List<Book>>

我一直在尝试这样做，但是没有成功。我们该怎么做？

Answer 1

我会做这样的事情

getBooks()
    .flatMapSingle(bookList -> Flowable.fromIterable(bookList)
        .flatMap(book -> getCategories(book.id)
            .map(categories -> {
                   book.setCategories(categories);
                   return book;
            }))
        .flatMap(book -> getAuthors(book.id)
            .map(authors -> {
                   book.setAuthors(authors);
                   return book;
             }))
          .toList())
    .subscribe(bookList -> {
        // done
    });

我认为这是第一次无效，因为您的Flowable<List<Book>>未完成并且toList()被卡住了。尝试嵌套flatMap，因为Flowable.fromIterable()在完成循环后完成，因此它应该无法工作。

我创建了这样的测试，效果很好 https://pastebin.com/Fus4MvXW

根据RxJava中的另一个Flowable <list <item2 >>修改Flowable <list <item >>中的每个项目

1 个答案: