RxJava：链接可观察量 [英] RxJava: chaining observables

问题描述

是否可以使用RxJava实现下一个链接：

Is it possible to implement something like next chaining using RxJava:

loginObservable()
   .then( (someData) -> {
      // returns another Observable<T> with some long operation
      return fetchUserDataObservable(someData);

   }).then( (userData) -> {
      // it should be called when fetching user data completed (with userData of type T)
      cacheUserData(userData);

   }).then( (userData) -> {
      // it should be called after all previous operations completed
      displayUserData()

   }).doOnError( (error) -> {
      //do something
   })

我发现这个库非常有趣，但无法计算我们如何将请求链接到彼此依赖的先前。

I found this library very interesting, but can't figure our how to chain requests where each other depends on previous.

推荐答案

当然，RxJava支持 .map 这是做什么的。来自RxJava Wiki：

Sure, RxJava supports .map which does this. From the RxJava Wiki:

基本上，它是：

loginObservable()
   .switchMap( someData -> fetchUserDataObservable(someData) )
   .map( userData -> cacheUserData(userData) )
   .subscribe(new Subscriber<YourResult>() {
        @Override
        public void onCompleted() {
           // observable stream has ended - no more logins possible
        }
        @Override
        public void onError(Throwable e) {
            // do something
        }
        @Override
        public void onNext(YourType yourType) {
            displayUserData();
        }
    });

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