问使用RxJava、Retrofit、RxKotlin flatmap依次调用多个接口

EN

public Single<List<Restaurant>> getRestaurants(int userId) {
  return ddApi.getUserInfo(userId).flapMap(user -> {
  return ddApi.getAvailableRestaurants(user.defaultAddress.lat, 
              user.defaultAddress.lng);
 });
}



public class RestaurantFragment {

private CompositeDisposables disposables = new CompositeDisposables();
private RestaurantDataSource restaurantDataSource;

@Override
public void onResume() {
// subscribe to the Single returned by RestaurantApi
restaurantDataSource
  .getRestaurants(userId)
  .subscribeOn(Schedulers.io())
  .observeOn(AndroidSchedulers.mainThread())
  .subscribe(new SingleObserver<Restaurant>() {
        @Override
        public void onSubscribe(Disposable d) {
            disposables.add(d);
        }

        @Override
        public void onSuccess(List<Restaurant> restaurants) {
            // update the adapter with restaurants
        }

        @Override
        public void onError(Throwable e) {
            // display an error message
        }
    });
}

 @Override
 public void onPause() {
   disposables.clear();
 }
}