qw

    @FXML
    void initialize() {
        change_format(calendar);
        calendar.valueProperty().addListener(new ChangeListener<LocalDate>() {
            @Override
            public void changed(ObservableValue<? extends LocalDate> observable, LocalDate oldValue, LocalDate newValue) {
                //System.out.println("changed " + oldValue + "->" + newValue);
                refresh_page();
            }
        });

        calendar.setValue(LocalDate.now());
        groups.add(new GroupPage(0, Controller.this));
        for (int i=2; i<MAX_GROUPS; i++) {                                                   // we assume 1.txt is there
            if (new File(Integer.toString(i) + ".txt").exists()) {
                group_pagination.setPageCount(group_pagination.getPageCount() + 1);
                groups.add(new GroupPage(i-1, Controller.this));
            }
            else
                break;
        }
        AllStudents.set_attendance();
        group_pagination.setPageFactory((Integer pageIndex) -> createPage(pageIndex));
    }

    private ListView<String> createPage(Integer pageIndex) {
        GroupPage group = groups.get(group_pagination.getCurrentPageIndex());
        result = new ListView<>(items = group.get_student_names());
        result.setOrientation(Orientation.VERTICAL);
        result.setPrefSize(450, 450);
        //result.setCellFactory(TextFieldListCell.forListView());
        //result.setCellFactory(TextFieldListCell.forListView());
        result.setEditable(true);
        if (lankomumas) {
            result.setCellFactory(CheckBoxListCell.forListView(new Callback<String, ObservableValue<Boolean>>() {
                @Override
                public ObservableValue<Boolean> call(String item) {
                    //BooleanProperty observable = new SimpleBooleanProperty(false);
                    BooleanProperty observable = new SimpleBooleanProperty(AllStudents.get_student(item).is_visited(calendar.getValue().toString()));
                    observable.addListener(new ChangeListener<Boolean>() {
                        @Override
                        public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) {
                            date_change(group.get_student(item), newValue);
                        }
                    });
                    //observable.set(true);
                    return observable;
                }
            }));
        }
        else {
            result.setCellFactory(TextFieldListCell.forListView());
        }

        result.setOnEditCommit(new EventHandler<ListView.EditEvent<String>>() {
            @Override
            public void handle(ListView.EditEvent<String> t) {
                change_student_name(t.getIndex(), t.getNewValue());
                result.getItems().set(t.getIndex(), t.getNewValue());
                //System.out.println(result.getItems(t.getIndex()));
                //change_student_name(t.getIndex(), t.getNewValue());
                //result.getItems().set(t.getIndex(), t.getNewValue());
            }
        });
        return result;
    }