AddRemoveSnippet.java

private void handleEvent(String eventName, Object data) {
    if (HorizontalArticlesFragment.ITEM_CLICKED.equals(eventName)) {
      Article article = (Article) data;
      getHorizontalArticlesFragment().removeArticle(article.dupe());
      getArticleGridFragment().addArticle(article.dupe());
    } else if (ArticleGridFragment.ITEM_CLICKED.equals(eventName)) {
      Article article = (Article) data;
      getArticleGridFragment().removeArticle(article.dupe());
      getHorizontalArticlesFragment().addArticle(article.dupe());
    }
 }

//somewhere else in the fragment

public void addArticle(Article article) {
   dataset.add(article);
}

public void removeArticle(Article article) {
  dataset.remove(article);
}

//somewhere else in the dataset

public void remove(Article article) {
  sortedList.beginBatchedUpdates();
  sortedList.remove(article);
  sortedList.endBatchedUpdates();
}

public void add(Article article) {
  sortedList.beginBatchedUpdates();
  sortedList.add(article);
  sortedList.endBatchedUpdates();
}