private void checkEvents() {
        boolean eventsOnly = !list.isEmpty();
        for (final Geocache cache : list) {
            if (!cache.isEventCache()) {
                eventsOnly = false;
                break;
            }
        }
        sortContext.getSort().setEventList(eventsOnly);
    }
Apply a new filter to the adapter (e.g. after filter was changed by user in menu)
main/src/main/java/cgeo/geocaching/ui/CacheListAdapter.java