code: private boolean isEventsCollide(WeekViewEvent event1, WeekViewEvent event2) {
          long start1 = event1.getStartTime().getTimeInMillis();
          long end1 = event1.getEndTime().getTimeInMillis();
          long start2 = event2.getStartTime().getTimeInMillis();
          long end2 = event2.getEndTime().getTimeInMillis();
          return !((start1 >= end2) || (end1 <= start2));
      }
docs: Checks if two events overlap.
  @param event1 The first event.
  @param event2 The second event.
  @return true if the events overlap.