title: RxJava, show updated list in Activity's onResume
body: <p>I need to fill the RecylcerView with list of data when activity starts. I implemented this by subscribe, where in onSuccess method I showing my list.
  But how can I again show updated list when Activity onResume. I mean after switching to another activity and then on returned to previous, I need to show updated RecylcerView again. How can I implemented this, or I need every time subscribe for showing. Maybe multiple subscribe on same observable in Activity's onResume is a bad practice?</p>
  
  <p>Presenter</p>
  
  <pre><code>@Override
  public void setCitiesList() {
      disposables.add(getCitiesListObservable()
              .subscribe(list -&gt; view.showCitiesList(list)));
  
  }
  
  private Single&lt;List&lt;City&gt;&gt; getCitiesListObservable() {
      Observable&lt;City&gt; citiesFromDb = dataManager.getCitiesFromDb();
      return citiesFromDb
             .switchMapSingle(city -&gt;
              // logic
  }
  </code></pre>
  
  <p>Activity </p>
  
  <pre><code>@Override
  protected void onResume() {
      super.onResume();
      presenter.setCitiesList();
  }
  </code></pre>
  
  <p>In a word, how can I avoid multiple subscribing? I need to show updated cities on each onResume.</p>