rxExample1.java

    button.setOnClickListener(v -> getData(new DataSubscriber()));

    public void getData(DataSubscriber subscriber) {
        Subscription s = apiEndpoints.getData()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(subscriber);
        compositeSubscriptions.add(s);
    }

    private class DataSubscriber extends Subscriber<Data> {
        @Override
        public void onCompleted() {
            //we are done, yey!
        }

        @Override
        public void onError(Throwable e) {
            showError("oh no!");
        }

        @Override
        public void onNext(Data data) {
            displayData(data);
        }
    }