JavaFX how to make the selected level from the dropdown menu affect the button?

Question

JavaFX

Hello. I have a play button that, when pressed, generates a table (this calls a method into which I pass the desired table size) and a menu with difficulty levels. How can I make the selected level in the menu affect the size of the generated table? Simply put, how to link a menu and a button?

@Override
    public void start(Stage stage) throws Exception {
        ObservableList<String> parameters = FXCollections.observableArrayList("9 x 9", "16 x 16", "25 x 25");
ComboBox<String> par = new ComboBox<String>(parameters);
        par.setValue("9 x 9");
Button play = new Button("Начать игру");
        VBox root = new VBox(par, play);

        Scene scene = new Scene(root, 600, 600);
        stage.setScene(scene);
        stage.setTitle("Судоку");
        stage.show();
play.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                TableFactory tablefactory = new TableFactory();
                int[][] board = tablefactory.generateBoard(9); // Вот сюда я передаю нужный размер таблицы
                tablefactory.printTheBoard(board);
            }
        });

Answer 1

Read the basics of javafx and javadoc components.