private void RetriveAllAppointment(ArrayList<String> id_list) {
 mrefDatabase = FirebaseDatabase.getInstance().getReference("Appointments").child("Active");
 mrefDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
 @Override
 public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
 if (dataSnapshot.exists()) {
 for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
 times_list = new ArrayList<>();
 for (DataSnapshot snapshot1 : snapshot.getChildren()) {
 appointmantdate = snapshot.child("Date").getValue().toString();
 selectedVenueName = snapshot.child("venueName").getValue().toString();
 if (snapshot.hasChild("times")) {
 for (DataSnapshot timesnapshot :snapshot.child("times").getChildren()) {
 String time = timesnapshot.getValue().toString();
 times_list.add(time);}
 CreateEvent(year, month);}

 public void CreateEvent(int year, int month) {
 String[] separated = appointmantdate.split("-");
 int year_ = Integer.parseInt(separated[0]);
 int month_ = Integer.parseInt(separated[1]);
 int day = Integer.parseInt(separated[2]);
 for (int a = 0; a < times_list.size(); a++) {
 String[] timeSplit = times_list.get(a).split(":");
 int time_hour = Integer.parseInt(timeSplit[0]);
 int time_minute = Integer.parseInt(timeSplit[1]);
 Calendar startTime = Calendar.getInstance();
 startTime.set(Calendar.HOUR_OF_DAY, time_hour);
 startTime.set(Calendar.MINUTE, time_minute);
 startTime.set(Calendar.DAY_OF_MONTH, day);
 startTime.set(Calendar.MONTH, month_ - 1);
 startTime.set(Calendar.YEAR, year_);
 Calendar endTime = (Calendar) startTime.clone();
 String[] endtimeSplit = times_list.get(times_list.size() - 1).split(":");
 int endtime_hour = Integer.parseInt(endtimeSplit[0]);
 int endtime_minute = Integer.parseInt(endtimeSplit[1]);
 endTime.add(Calendar.HOUR, endtime_hour);
 startTime.set(Calendar.MINUTE, endtime_minute);
 endTime.set(Calendar.MONTH, month - 1);
 event = new WeekViewEvent(1, selectedVenueName, startTime, endTime);
 event.setColor(getActivity(). getResources().getColor(R.color.event_color_03));
 events.add(event);}

 onMonthChange method

@Override
 public List<? extends WeekViewEvent> onMonthChange(int newYear, int newMonth) {
 List<WeekViewEvent> lastone = new ArrayList<WeekViewEvent>();
 
 if (appointmantdate != null && times_list != null) {
 lastone = CreateEvent(newYear, newMonth);
 events.addAll(lastone);
 }
 ArrayList<WeekViewEvent> matchedEvents = new ArrayList<WeekViewEvent>();
 for (WeekViewEvent event : events) {
 if (eventMatches(event, newYear, newMonth)) {
 matchedEvents.add(event);
 }
 return matchedEvents;