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Questions tagged [vaadin-flow]

Use the [vaadin] and [vaadin-flow] tags for any posts relating to the use of Vaadin Flow. For posts related to any other Vaadin topic, such as Fusion or a specific component, instead tag the post with its corresponding tag, for example: [vaadin-fusion] or [vaadin-upload], respectively.

Vaadin Flow is the new generation of the user-interface toolkit for building professional-looking, business-oriented single-page web apps in Java. Now based on standard Web Components technology.

Vaadin Flow is the major re-write of the venerable Vaadin Framework tool for building professional-looking business-oriented user-interfaces for web apps. This new generation of Vaadin replaces the internal use of GWT with the use of modern Web Components technology.

Vaadin apps are written in Java, executing server-side in a Java Servlet web container. At runtime Vaadin automatically renders a web-standards based user-interface in the client-side web browser via HTML, CSS, JavaScript, DOM, AJAX, XML & JSON, WebSocket, and Push technologies, all done transparently to the Java programmer.

The current Long Term Support (LTS) version of Vaadin is 14. The previous LTS version is 10. Version 10 succeeded Vaadin 8 (Framework).

The current major version is 22.

The next LTS version will be version 23, slated for March 2022.

1023 questions
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Vaadin Flow app switch between light and dark modes automatically

Vaadin Flow 14 ships with light and dark versions of its two bundled themes, Lumo and Material. And now browsers can ask the host OS for the user’s preference for light or dark modes. Is there a way to have a Vaadin app automatically use the light…
Basil Bourque
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Why is the Guava library included with Vaadin 14 not appearing on my project's classpath?

Vaadin 14.1.0alpha4 automatically includes the Google Guava version 25 library via its Maven configuration. See the screenshot below, listed on the left side. Yet in my own code, when referring to a class in Google Guava, IntelliJ marks it as a…
Basil Bourque
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Where to store `UI`-object scoped state in a Vaadin 14 app?

Context (web app) To store state available to our entire Vaadin app, we can get and set "Attribute" on the VaadinContext object that represents our entire Vaadin-based web app at runtime. These attributes act as a key-value collection, where the key…
Basil Bourque
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Why do I get NullPointerException with @Autowired Repository in Vaadin / SpringBoot application?

I am starting to build a web application with vaadin and spring boot. I want to create a vaadin site which lists data from a MSSQL Server in a grid. I always get NullPointerException when trying to use my @Autowired CrudRepository. I have read…
tigu
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User Sessions with Vaadin Flow

I am currently a budding Java developer that wants to get into Vaadin development and currently trying to implement User Session login for my application. I have read about the content regarding the usage of VaadinServlets to do so :…
Cheong Ming Lun
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Handling login with a Vaadin Flow webapp, across all layouts globally and across "route" URLs

Vaadin 8 In Vaadin 8, in my UI subclass I handled login by examining if a user’s session carried an attribute noting whether they had successfully logged in or not. If not, my UI subclass displayed a login layout rather than other content with…
Basil Bourque
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How to manage sessions in Vaadin 10?

I have a web page in Vaadin 10 that process files. How do I make different user have different sessions? When I try to open my page in different browsers to process files I get: java.lang.IllegalStateException: Cannot access state in VaadinSession…
John
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Enter press event for vaadin 10 TextField

Is there any specific way to add shortcut Listener for the Enter Key on a specific TextField element in Vaadin Flow. The documentation is silent about this.
Aiden
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Vaadin 23 not resolving URL's, instead showing errorpage

Problem summary: we've upgraded our Java 17 monolith application with multiple modules from Vaadin 21.0.1 to 23.3.5 and now our application routes don't resolve anymore, instead resulting in 404 Whitelabel errorpages. This not being our first Vaadin…
Paul
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Java double colon (::) operator equivalent in Scala

I've seen a few examples of how to write :: equvalant in Scala, for eg passing System.out::println to a function, but I'm unable to figure out how to write this Vaadin Grid component in Scala: Grid grid = new Grid<>(Person.class,…
TiN
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Creating a hierarchical menu in Vaadin 23

I returned to the Vaadin ecosystem after some years out and I can't find the good old Tree component for creating a left navigational menu hierarchies in Vaadin 23. What I found is a TreeGrid, however, it is explicitly stated in the docs, that it is…
Kivan
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Vaadin and markdown

I searched through the Vaadin documentation but couldn't find a way to render markdown. Is there a widget allowing that ? Or should I convert markdown into HTML ?
BenjaminD
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Problems deploying a Vaadin App to production

I'm working with Java 8 and Vaadin 22. When I want to deploy my starter app to production by mvnw clean package -Pproduction I find several problems while it is building the frontend. It is continuously saying "Cannot find module 'name of module'".…
Tomás Atrat
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Vaadin-flow non-critical validation that still returns isValid=true

we are currently trying to implement a non-critical validation layer that checks field inputs against certain validators without marking the form as "not valid", but rather as "out of specification" so that we can highlight the fields to the user.…
Benedikt Schmidt
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Vaadin Grid sortable date column

i want to add a sortable date column to my vaadin grid component. Unfortunately it doesn't work with formatted dates, I think after formatting the date object it is just a String and therefore sorting with this column doesn't work correctly, but I…
Hakan Akkurt
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