Change icon on a selected row in a Vaadin Grid

Question

So, I have a grid called "eventGrid". I added a component column with a down-arrow icon. When a user clicks on a row, addition information is displayed for that row. I want to change the down arrow to an up arrow for the selected row. How can I achieve this?

 eventGrid.addColumn(Person::getFirst).setHeader("First Name");
    eventGrid.addColumn(Person::getLast).setHeader("Last Name");
    eventGrid.addColumn(Person::getNumber).setHeader("Phone Number");


 eventGrid.addComponentColumn(item -> {
      Icon icon = new Icon("lumo", "angle-down");
      return icon;
    }).setWidth("6em").setFlexGrow(0);

Answer 1

Assuming you have an in-memory DataProvider:

        Grid<Person> eventGrid = new Grid<Person>();
        eventGrid.addColumn(Person::getFirst).setHeader("First Name");
        eventGrid.addColumn(Person::getLast).setHeader("Last Name");
        eventGrid.addColumn(Person::getNumber).setHeader("Phone Number");
        eventGrid.addComponentColumn(item -> {
            Icon icon = new Icon("lumo", "angle-down");
            if (item.equals(eventGrid.asSingleSelect().getValue())) {
                icon = new Icon("lumo", "angle-up");
            }
            return icon;
        }).setWidth("6em").setFlexGrow(0);
        eventGrid.addSelectionListener(e -> {
            eventGrid.getListDataView().refreshAll();
        });