public void updateHomeBadge(final int delta) {
        if (delta == 0) {
            return;
        }
        final int badgeColor;
        synchronized (hasHighPrioNotification) {
            badgeColor = hasHighPrioNotification.get() ? 0xffff0000 : 0xff0a67e2;
        }
        synchronized (lowPrioNotificationCounter) {
            lowPrioNotificationCounter.set(lowPrioNotificationCounter.get() + delta);
            final BadgeDrawable badge = ((NavigationBarView) binding.activityNavigationBar).getOrCreateBadge(MENU_HOME);
            badge.clearNumber();
            badge.setBackgroundColor(badgeColor);
            badge.setVisible(lowPrioNotificationCounter.get() > 0);
        }
    }
detect whether c:geo is unable to log in
main/src/main/java/cgeo/geocaching/activity/AbstractNavigationBarActivity.java