java - RxJava缝制两个查询

Question

如何在 RxJava 中缝合两个 Observable ？

Observable<List<CalendarEvent>> ，对于每个 CalendarEvent，我想做网络操作来读取(lat，lon)并获取地名，然后将地名组合回 CalendarEvent。

 public Observable<List<CalendarEvent>> getEvents() {
     // get events
     // translate each Event LatLng to Place and bind it to Event
     // return the events
 }

Answer 1

public Observable<List<CalendarEvent>> getEvents() {
    List<CalendarEvent> sourceList = ...
    return Observable.from(sourceList) //emits each item separately
            .concatMap(calendarEvent -> applyPlaceName(calendarEvent)) //fetches places  and applies them for each item
            //fyi: concatMap executes requests sequentially, if you want do it in parallel - use flatMap instead
            .toList(); //collects items to list
}

//somewhere in your Networking class
public Observable<CalendarEvent> applyPlaceName(CalendarEvent calendarEvent) {
    return Observable ... //do network call and apply placeName on item
}

//p.s. don't forget to apply appropriate Schedulers