Multi ComboBox for Vaadin Flow

Description

The Multicombobox component provides support to select multiple items for a dropdown.

It's optimized to be used with a keyboard:

  • Filtering selects the first non-selected item
  • Enter toggles the selection
  • Arrow up/down to navigate to the next/previous item.

"Select All" selects all the items.

"Cancel" closes and resets the selection (replace the current value with the value when the user opened the combobox)

It's recommended to use the page size to activate the filtering on client side.

Usage

Create a new component MultiComboBox and use it like a ComboBox. The API is quite similar.

The value returned is a Set of beans.

Limitations

  • Custom value does not work, you can't add value that are not in the list.
  • This add-on implements HasHelper, so it requires Vaadin 14.4+.

Examples

Basic example

    public SimpleView() {
        MultiComboBox<Person> combobox = new MultiComboBox<>();
        combobox.setLabel("Persons");
        List<Person> personList = getItems();
        combobox.setItems(personList);
        add(combobox);
    }

    private List<Person> getItems() {
        PersonService personService = new PersonService();
        return personService.fetchAll();
    }

Item label Generator

    public LabelGeneratorView() {
        List<Person> personList = getItems();
        MultiComboBox<Person> combobox = new MultiComboBox<>();
        combobox.setLabel("Persons Phone");
        combobox.setItemLabelGenerator(person -> {
            if (person.getEmail() != null) {
                return person.getPhoneNumber();
            } else {
                return "No phone for " + person.getId();
            }
        });
        combobox.setItems(personList);
        add(combobox);
    }

    private List<Person> getItems() {
        PersonService personService = new PersonService();
        return personService.fetchAll();
    }

Client side filtering

You can set a page size > your list size to enable the filtering on the client side.


    private Span itemsSelected = new Span();

    public InMemoryView() {
        MultiComboBox<Person> combobox = new MultiComboBox<>(1000);
        combobox.setLabel("Persons");
        List<Person> personList = getItems();
        combobox.setItems(personList);
        add(combobox);

        HashSet<Person> value = new HashSet<>();
        value.add(personList.get(0));
        value.add(personList.get(5));
        combobox.setValue(value);
        combobox.addValueChangeListener(e -> {
            if (e.getValue() != null) {
                itemsSelected.setText("Items selected:" + e.getValue().toString());
            } else {
                itemsSelected.setText("No item selected");
            }

        });
    }

    private List<Person> getItems() {
        PersonService personService = new PersonService();
        return personService.fetchAll();
    }

Binding and validation

    private BackendBean backendBean = new BackendBean();
    private Binder<BackendBean> binder = new Binder<>();

    public BindingView() {

        MultiComboBox<Person> combobox = new MultiComboBox<>();
        combobox.setLabel("Persons");
        List<Person> personList = getItems();
        combobox.setItems(personList);
        HashSet<Person> value = new HashSet<>();
        value.add(personList.get(0));
        value.add(personList.get(5));
        backendBean.setPersons(value);
        add(combobox);
        binder.setBean(backendBean);
        binder.forField(combobox).asRequired().withValidator(val -> {
            return (val != null) && (val.size() == 2);
        }, "You have to select exactly 2 persons")
            .bind(BackendBean::getPersons,BackendBean::setPersons);
    }

    private List<Person> getItems() {
        PersonService personService = new PersonService();
        return personService.fetchAll();
    }

    public static class BackendBean {
        private Set<Person> persons;

        public Set<Person> getPersons() {
            return persons;
        }

        public void setPersons(Set<Person> persons) {
            this.persons = persons;
        }
    }

Demo

You can check the demo here: https://incubator.app.fi/multi-combo-box-flow-demo/

Missing features or bugs

You can report any issue or missing feature on github: https://github.com/vaadin-component-factory/multiselect-combo-box

Install

Link to this version
ExperimentalReleased 21 December 2020Apache License 2.0
Framework Support
Vaadin platform 14
Install with
Release notes - Version 0.4.0
  • Avoid an infinite loop when more than 500 items are selected
  • Fix the style of the Select all / Clear buttons