README.md

Vaadin on Grails 3 Example

This example application is again based upon the examples within the Vaadin manual "Book of Vaadin", but this project uses Grails 3 and an alternative Vaadin plugin.

If you have SDKMAN (the latest version of GVM) installed you can switch between versions of Grails with, for example,

sdk default grails 3.0.9
sdk default groovy 2.4.5

Getting Started with Vaadin for Grails 3

This project was created within IntelliJ Idea. Some instructions are available on github and within the documentation The following instructions may be useful if starting a new project.

1. Install Grails 3 and Groovy 2.4.5

2. Create a Grails 3 project within the IDE

3. Add the repo vaadin/grails3 plugin repo to your build.gradle file.
   IMPORTANT: this should go in the repositories { ... } section and NOT the buildscript { repositoriies { ...} } section!

   maven { url "https://dl.bintray.com/vaadin-for-grails/plugins" }
   

4. Add the plugin dependency to your build.gradle file..

   compile 'org.grails.plugins:vaadin7:3.+'
   

5. Finally execute the grails command grails vaadin-quickstart com.yourcompany and run your app. If you get an error message Error Could not resolve all dependencies for configuration ':testRuntime' then you have probably added the maven url to the wrong 'repositories { ... }' section in build.gradle.

6. Run the gradle build

7. If you want to use conf/vaadin.yml to list out the views and navigation then your root url must include a hash-bang #! or else it will fail 'Trying to navigate to an unknown state'. (I think this is a bug in the plugin). For example,

   mappings:
   
   - uri: '/vaadin#!'
     theme: 'grails'
     pageTitle: 'Vaadin for Grails 3'
     view: 'app.views.StartView'
   

   You can implement your own Vaadin UI, as per the Grails 2 plugin example if you prefer.

Running this project

Vaadin for Grails 3 runs Vaadin alongside Grails. If you access the root of the application you will reach Grails content; if you access paths which are mapped to Vaadin, you will get Vaadin content.

So when this project runs if you go to http://localhost:8080 you will get a Grails/GSP page; the vaadin aspect of the application is at http://localhost:8080/vaadin

Navigator

If using the conf/vaadin.yml mappings, there is no need to use the Navigator directly - unlike the Grails 2 example.

Declarative Design

Vaadin for Grails 3 can use declarative design, but you have to put the design HTML files on the classpath. I have only been able to get this to work by placing the images in grails/conf/. However it should be possible to add custom gradle build tasks to store the files elsewhere.
In this project they are hosted in grails-app/conf/app/views.

Static Content

In the original example in the Book of Vaadin, it contains cartoon pictures of various animals which are served as images. In the example, these images are part of the Vaadin 'reindeer' theme; however, these images are not present in the theme - at least, not in Vaadin v7.5.

Static assets which are not handled by the Asset Pipeline can be placed in src/main/resources/public and accessed with,

pic.source = new ExternalResource("/cat-128px.png")

Its not yet clear how to access assets in the asset pipeline as there is no runtime I can get working!

References

• Vaadin For Grails Documentation
• Vaadin For Grails 3 plugin