如何在vaadin中使用标题复选框选中所有复选框

List<Person> people = Arrays.asList(
            new Person("Nicolaus Copernicus", 15),
            new Person("Galileo Galilei", 15),
            new Person("Johannes Kepler", 15));
     TextField txt =new TextField();
      CheckBox chk=new CheckBox();
        // Create a grid bound to the list
        Grid<Person> grid = new Grid<>();
        grid.setItems(people);
        grid.addColumn(Person::getName).setCaption("Name");
        grid.addColumn(Person::getAge).setCaption("Year of birth");
       grid.addColumn(Person-> new TextField());


        layout.addComponents(grid);


    setParent(layout);