virtualList

LIVE DEMO

The virtualList component is designed for displaying lists of items with a complex content. Only the visible portion of items is rendered at a time.

  • XML element: virtualList

  • Java class: JmixVirtualList

Basics

virtualList is connected to a data container. By default, it shows the instance name of the entity in the container. Using the renderer handler, you can display custom content.

virtual list basics

Below is an example of using virtualList in a list view instead of dataGrid:

<data>
    <collection id="usersDc" class="com.company.onboarding.entity.User">
        <loader id="usersDl" readOnly="true">
            <query>
                <![CDATA[select e from User e]]>
            </query>
        </loader>
        <fetchPlan extends="_base"/>
    </collection>
</data>
<layout>
    <virtualList id="virtualList" itemsContainer="usersDc"/>
</layout>
@Autowired
private Messages messages;

@Autowired
protected MetadataTools metadataTools;

@Autowired
private FileStorage fileStorage;

@Autowired
private UiComponents uiComponents;

@Supply(to = "virtualList", subject = "renderer")
private Renderer<User> virtualListRenderer() {
    return new ComponentRenderer<>(this::createUserRenderer);
}

protected HorizontalLayout createUserRenderer(User user) {
    HorizontalLayout cardLayout = uiComponents.create(HorizontalLayout.class);
    cardLayout.setMargin(true);
    cardLayout.addClassNames(LumoUtility.Border.ALL,
            LumoUtility.BorderColor.CONTRAST_10,
            LumoUtility.BorderRadius.MEDIUM);

    Image image = uiComponents.create(Image.class);
    FileRef fileRef = user.getPicture();
    if (fileRef != null) {
        image.setWidth("50px");
        image.setHeight("50px");
        StreamResource streamResource = new StreamResource(
                fileRef.getFileName(),
                () -> fileStorage.openStream(fileRef));
        image.setSrc(streamResource);
    }

    VerticalLayout infoLayout = new VerticalLayout();
    infoLayout.setSpacing(false);
    infoLayout.setPadding(false);

    HorizontalLayout itemDetailLayout = new HorizontalLayout();
    itemDetailLayout.add(new Text(user.getUsername()));
    itemDetailLayout.add(new Html(
            messages.formatMessage(getClass(), "statusDescription",
                    user.getOnboardingStatus() == null ? ""
                            : metadataTools.format(user.getOnboardingStatus()))));

    itemDetailLayout.setPadding(false);
    itemDetailLayout.setAlignItems(FlexComponent.Alignment.CENTER);

    H4 userName = new H4(user.getFirstName() + " " + user.getLastName());

    infoLayout.add(userName);
    infoLayout.add(itemDetailLayout);

    cardLayout.add(image,infoLayout);
    return cardLayout;
}

Note that items in virtualList can’t be selected or navigated using the keyboard. The standard List Component Actions will not work with virtualList. If needed, define your own actions for CRUD operations.

Inline Editor

LIVE DEMO

You can use virtualList to build an inline editor. Check out an example in the UI Samples application.

Attributes

id - alignSelf - classNames - colspan - css - enabled - focusShortcut - height - itemsContainer - itemsEnum - maxHeight - maxWidth - minHeight - minWidth - tabIndex - visible - width

itemsContainer

Sets the name of a data container which contains a list of items. The component will display the entity’s instance name.

itemsEnum

LIVE DEMO

Defines the enumeration class for creating a list of items.

Handlers

AttachEvent - BlurEvent - DetachEvent - FocusEvent - Renderer - ValueProvider

To generate a handler stub in Jmix Studio, use the Handlers tab of the Jmix UI inspector panel or the Generate Handler action available in the top panel of the view class and through the Code → Generate menu (Alt+Insert / Cmd+N).

Renderer

A custom renderer for list items can only be set in the view controller using Java code.

You can use the setRenderer() method or @Supply annotation to do this.

  • Example of using @Supply annotation:

    @Supply(to = "usersVirtualList", subject = "renderer")
private Renderer<User> usersVirtualListRenderer() {
    return new ComponentRenderer<>(user -> {
        Button button = uiComponents.create(Button.class);
        button.setText(user.getFirstName() + ", " + user.getLastName());
        return button;
    });
}

  • Example of using the setRenderer() method:

    @Subscribe
public void onInit(final InitEvent event) {
    ComponentRenderer<Button, User> renderer = new ComponentRenderer<>(user -> {
        Button button = uiComponents.create(Button.class);
        button.setText(user.getFirstName() + ", " + user.getLastName());
        return button;
    });
    usersVirtualList.setRenderer(renderer);
}

ValueProvider

It’s possible to specify a renderer using ValueProvider if you want to display plain text.

See Also

See Vaadin Docs for more information.