This One Line of Code Can Change Your Entire Vaadin App’s Look

This article is part of the series: 'Towards Vaadin Developer Certification,' which aims to explain the fundamentals of Vaadin while I study for this certification. The topics covered here are an integral part of the 'Vaadin Developer' Certification. Theming is a fundamental aspect of any Vaadin application, allowing developers to define the look and feel of their UI. In Vaadin, themes are applied using the @Theme annotation, which provides flexibility to choose between predefined themes like Lumo or create fully customized ones. This article explores how @Theme works and its variations. @Theme @Theme 1. Applying a Theme with @Theme 1. Applying a Theme with @Theme The @Theme annotation is used to specify the theme for a Vaadin application. By default, if no theme is set, the application uses Lumo. However, we can explicitly declare it: @Theme Additionally, we can define theme variants like Lumo.DARK: Lumo.DARK 2. Disabling Themes with @NoTheme 2. Disabling Themes with @NoTheme Sometimes, a specific view might need to be rendered without any theme, even the default Lumo theme. This is where @NoTheme comes into play: @NoTheme However, disabling themes entirely is not recommended unless absolutely necessary. Instead, extending and modifying Lumo is the preferred approach. Conclusion Conclusion The @Theme annotation provides a structured way to apply theming in Vaadin applications. Whether using predefined themes like Lumo or creating custom themes, understanding how to manage them effectively ensures a consistent user experience while maintaining flexibility in UI design. @Theme Disclaimer Disclaimer This content is drawn from studies and notes related to the Vaadin 24 certification. For deeper details, please consult the official documentation and learning materials for Vaadin certification. AI tools assisted in the structuring of this content; however, the writing and original content are solely done by the author. Authors Authors Paulo B. A. is an 'Oracle Certified Java Developer' and 'Spring Certified Professional' with a deep passion for Vaadin Flow. He crafts UIs with Vaadin and strives to make it the leading frontend framework for full-stack Java developers worldwide. He loves teaching, sharing knowledge, and creating content. While he enjoys learning theory through certifications, he always advocates for a practical approach. Linkedin.com/in/pbalves X.com/p_b_alves Mastodon.social/@pbalves Linkedin.com/in/pbalves X.com/p_b_alves Mastodon.social/@pbalves Staff Writer: Fábio A. P. is a technology enthusiast, self-taught writer, and scholar of society's relationship with technology. Passionate about sharing insights, he provides reliable perspectives on how technology shapes our lives. With clear and precise writing, Fábio simplifies complex topics, empowering readers to navigate the digital age with confidence. Staff Writer: Staff Writer: Medium.com/@fabioape Medium.com/@fabioape