CODEWITHSUNDEEP
javascriptjavaspring-bootvaadin
George Z.
George Z.

Reputation: 6808

TextArea does not scroll to maximum bottom

I have a text area with long text and I want when the view shows up to be scrolled to maximum bottom:

TextArea textArea = new TextArea();
textArea.setValue(createLongText());
textArea.setHeight("500px");
textArea.setMaxHeight("500px");
textArea.setWidthFull();

textArea.setReadOnly(false);
textArea.getElement().executeJs("this.inputElement.scrollTop = 500");
//text.setReadOnly(true);
textArea.getStyle().set("overflow-y", "auto ! important");
add(currentComponent = textArea);

I tried all of the followings based on things I found on the web:

text.getElement().executeJs("this.inputElement.scrollTop = 1000"); //or scrollHeight

text.getElement().executeJs("this.scrollTop = 1000"); //or scrollHeight

text.getStyle().set("overflow-y", "auto ! important");

textArea.getElement()
        .executeJs("this.inputElement.selectionStart= 1000;this.inputElement.selectionEnd= 1001;");

but none of these works.

Here is my complete view:

@Route("")
@PWA(name = "Project Base for Vaadin Flow with Spring", shortName = "Project Base")
@Secured("ROLE_ADMIN")
public class DashboardView extends VerticalLayout {

    private Component currentComponent;

    @Autowired
    public DashboardView() {
        Button longButtonText = new Button("Long textarea");
        longButtonText.addClickListener(e -> {
            if (currentComponent != null)
                remove(currentComponent);

            TextArea textArea = new TextArea();
            textArea.setValue(createLongText());
            textArea.setHeight("500px");
            textArea.setMaxHeight("500px");
            textArea.setWidthFull();

            textArea.setReadOnly(false);
            textArea.getElement().executeJs("this.inputElement.scrollTop = 500");
//          text.setReadOnly(true);
            textArea.getStyle().set("overflow-y", "auto ! important");
            add(currentComponent = textArea);
        });

        Button logoutButton = new Button("logout");
        logoutButton.addClickListener(e -> {
            UI.getCurrent().getSession().close();
            SecurityContextHolder.getContext().setAuthentication(null);
            SecurityContextHolder.clearContext();
            UI.getCurrent().getPage().setLocation("/login");
        });

        add(new HorizontalLayout(longButtonText, logoutButton));

        longButtonText.click();
    }

    private String createLongText() {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < 2000; i++) {
            sb.append(UUID.randomUUID().toString());
            sb.append(System.lineSeparator());
        }
        return sb.toString();
    }
}

My vaadin.version: <vaadin.version>14.1.17</vaadin.version>

What should I do in order to achieve it?

Upvotes: 0

Views: 417

Answers (1)

Leif &#197;strand
Leif &#197;strand

Reputation: 8001

The element that actually scrolls is in the middle of the DOM hierarchy rather than either the top-level component or the inputElement. I didn't spot any direct way of accessing this element, so you need to use a little indirection in the form of this.inputElement.parentElement.parentElement.

To scroll to the end, you thus need to do textArea.getElement().executeJs("this.inputElement.parentElement.parentElement.scrollTop = this.inputElement.parentElement.parentElement.scrollHeight");.

It should also be mentioned this approach is dependent on implementation details related to the internal structure of the component. This means that there's a risk that the structure is changed in some future version without that change being treated as a breaking change.

Upvotes: 1

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