Rxjava链式多于一个请求

Rxjava chain more than one request

我是 RxJava 的新手。 我想链接一些电话:

Observable<RoomList> listRoomsCall = mRoomServiceApi.listRooms();

//这个电话会给我 RoomIds 下一步是调用所有 RoomIds - 请求后请求

mMeetingServiceApi.listMeetings(roomID, startsAtString, endsAtString, free))

我应该如何将第一个调用与下一个调用链接起来?

我认为我应该使用 flatMap 并循环调用所有请求,但如何在最后连接所有响应?

  listRoomsCall.flatMap(v -> {
            for (ExchangeRoom exchangeRoom : v.getExchangeRoomList()) {
               mMeetingServiceApi.listMeetings(roomID, startsAtString, endsAtString, free);
            }
        })

将内部列表再次变成 ObservableflatMap

listRoomsCall
.flatMapIterable(v -> v.getExchangeRoomList())
.flatMap(exchangeRoom -> {
    mMeetingServiceApi.listMeetings(roomID, startsAtString, endsAtString, free);
})
.subscribe(/* */);

listRoomsCall
.flatMap(v -> 
     Observable.fromIterable(v.getExchangeRoomList())
     .flatMap(exchangeRoom -> {
         mMeetingServiceApi.listMeetings(roomID, startsAtString, endsAtString, free);
     })
)
.subscribe(/* */);