Vaadin 7 UI Design By Example Beginner's Guide

Time for action – showing the results

The default behavior of the application is to show only the results of the last execution. We need to remove all the results that have been previously added to the resultsLayout component if the user has not checked Keep previous results. To do that, implement your showResults method:

private void showResults(Collection<String> results) {
  if(!checkBox.getValue()) {
    resultsLayout.removeAllComponents();
    
  } else if(resultsLayout.getComponentCount() > 0) {
    resultsLayout.addComponent(new Label("--"));
  }
  
  for(String result : results) {
    resultsLayout.addComponent(new Label(result));
  }
}

What just happened?

If the checkbox is not checked, we can remove all the components in resultsLayout (not in layout, we don't want baffled ...