controls.pde

//here we setup the dropdown list.
void customize(DropdownList ddl) {
  ddl.setBackgroundColor(color(190));
  ddl.setItemHeight(20);
  ddl.setBarHeight(15);
  
  ddl.addItem("Filter", 0);
  ddl.addItem("1Euro", 1);
  ddl.addItem("No Filter", 1);
  
  ddl.setColorBackground(color(60));
  ddl.setColorActive(color(255, 128));
}

void controlEvent(ControlEvent theEvent) {
  // DropdownList is of type ControlGroup.
  // A controlEvent will be triggered from inside the ControlGroup class.
  // therefore you need to check the originator of the Event with
  // if (theEvent.isGroup())
  // to avoid an error message thrown by controlP5.

  if (theEvent.isGroup()) {
    // check if the Event was triggered from a ControlGroup
    println("event from group : "+theEvent.getGroup().getValue()+" from "+theEvent.getGroup());
    filterMode = (int)theEvent.getGroup().getValue();
  } 
  else if (theEvent.isController()) {
    println("event from controller : "+theEvent.getController().getValue()+" from "+theEvent.getController());
  }
}