Apps keep showing progressdialog on screen rotation

[Asaak]

Hi!

I have an activity where I have to do som background tasks. I am using a observable/subscriber with rxandroid. Just before starting the background task I show a progressdialog and when the job is done I dissmiss it. Problem is, if I rotate the screen, progressdialog dissapear. What I want is to keep showing progressdialog until the background task finishs.

This is my code:

private Subscriber suscriptor;

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        suscriptor = new Subscriber() {
            @Override
            public void onCompleted() {
                progressDialog.dismiss();
                Log.d("SUSCRIPTOR","ON COMPLETE");
            }

            @Override
            public void onError(Throwable e) {
                Log.d("SUSCRIPTOR","ON ERROR");
            }

            @Override
            public void onNext(Object o) {
                Log.d("SUSCRIPTOR","ON NEXT");
            }
        };

//at some point when a button is clicked

reset_database.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference preference) {

                ACTION = LOAD_DATA;
                progressDialog = ProgressDialog.show(getActivity(), getString(R.string.dialog_carga_configuracion_background),getString(R.string.dialog_carga_porfavor_espere), false, false);

                backgroundTask();
                return true;


            }
        });

private void backgroundTask()
    {
        setRetainInstance(true);
       Observable.create(
                new Observable.OnSubscribe<String>() {
                    @Override
                    public void call(Subscriber<? super String> sub) {
                        accionBackground();
                        try {
                            Thread.sleep(5000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        sub.onNext("cargar");
                        sub.onCompleted();

                    }

                    @Override
                    protected void finalize() throws Throwable {
                        super.finalize();
                        Log.d("OBSERAVBLE","FINALIZADO");
                    }
                })
        .observeOn(AndroidSchedulers.mainThread())
        .subscribeOn(Schedulers.newThread())
               .cache()
        .subscribe(suscriptor);

@Override
public void onDestroy()
{
    if(suscriptor!=null)
    {
        if(!suscriptor.isUnsubscribed())
        {
            suscriptor.unsubscribe();
        }
    }

    super.onDestroy();
}

When I rotate screen is not crashing but I am not sure it is finishing job completely. 

Any ideas how to do what I want?

Thanks!