How to update a firebase list?

Question

Android

Good day to all. Need help. When I switch the date, I want the list (of clients from Firebase) to change, through the method I display the date for the current moment, everything works fine, but when I click on another day, the list is not updated. Can you please tell me how to update the list?

Calendar c = Calendar.getInstance();
        SimpleDateFormat sdf = new SimpleDateFormat("dd_MM_yyyy");
        Date date = new Date();
        calendarView = (CalendarView) findViewById(R.id.calendarView);
        selectedDate = sdf.format(date);
        try {
            calendarView.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
                @Override
                public void onSelectedDayChange(@NonNull CalendarView calendarView, int year, int month, int dayOfMonth) {
                    int mYear = year;
                    int mMonth = month;
                    int mDay = dayOfMonth;
                    selectedDate = new StringBuilder().append(mDay).append("_").append(mMonth + 1).append("_")
                            .append(mYear).toString();
                    Toast.makeText(MainActivity.this, selectedDate, Toast.LENGTH_SHORT).show();
                    result.clear();
                    reference = database.getReference(selectedDate);

                }
            });
        } catch (NullPointerException e) {
        }

The database is only full for 2 days. When you click on May 10, it does not display data from the table