给定的汽车列表(汽车List<Car> cars ),我可以这样做: Observable.just(cars); //returns an Observable that emits one List<Car> Observable.from(cars); //returns an Observable that emits a squence of Car 有没有办法从一个List<Car>的Observable<Car>到一个Observable<Car>的序列? 像没有参数的东西 Obserable.just(cars).from()