Question about delete operation

[requery]

Question about delete operation

[npurushe]

Hi. The issue here is delete().get() just creates the operation of type Scalar<Integer> that has to evaluated. You can evaluate it by calling value() or consume(Consumer<? super E> action). Something like:

Integer rowsDeleted = MyApplication.getInstance().getData().toBlocking().delete(City.class).get().value();
List<City> wasCities=MyApplication.getInstance().getData().select(City.class).get().toList(); // will be empty now

Will make this more clear in the examples and documentation. Sorry about any confusion. Thanks for reporting!

[oleonov]

Thanks! Looks complicated)

[npurushe]

The reason for that is the API is designed to be fully non-blocking/reactive. I agree its a little bit more complicated in blocking use cases, there will be some improvements there

[oleonov]

I know, but using retrofit+rxAndroid I need blocking operation inside onNext. How can I do it simpler?

NetworkApi.getServerApi().getCities()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Observer<List<City>>() {
                    @Override
                    public void onCompleted() {
                        sendBroadcast(new Intent(BroadcastHelper.ACTION_CITY_LOADED));
                        System.out.println("onCompleted");
                    }

                    @Override
                    public void onError(Throwable e)
                    {
                        ...
                    }

                    @Override
                    public void onNext(List<City> cities) {
                        System.out.printf("onNext %s\n", cities);
                        if(cities!=null)
                        {
                            MyApplication.getInstance().getData().toBlocking().delete(City.class).get().value();
                            MyApplication.getInstance().getData().toBlocking().insert(cities);
                        }
                    }
                });

[npurushe]

I'm not sure that's what you want because then you are doing the database operations on the main thread then. You probably want to use the rx map() operator to apply functions to the observable which can do the database work before the final subscription.

[oleonov]

Thank you! I did so and get more speed for UI.