Images & Icons
Images and icons are the basic custom visual elements to add visual content, guides, and style. You can display images using the Image component. Many web components allow you to display an icon along with a title or inside the component.
The Image Component
The Image component allows you to embed images. It’s a wrapper around the HTML <img> element. You can display either static images or images generated on the fly.
Static Resources
A servlet container can serve images as static resources. This is more efficient than streaming them through the application, as described later. You can also serve static resources from a frontend server.
Image image = new Image("images/myimage.png", "My Alt Image");
add(image);The second parameter to the constructor is alternative text, which is displayed if the image can’t be displayed for some reason. It’s also used in assistive technologies.
The location of static image resources in the project depends on the deployment method:
- Web Archive (WAR) packaging
-
Under
/src/main/webapp, such as/src/main/webapp/images/myimage.png. - JAR packaging (Spring Boot applications)
-
Under
/src/main/resources/META-INF/resources, such as/src/main/resources/META-INF/resources/images/myimage.png.
The access URL of the image resource depends on how the application is deployed.
If the resources are deployed under the application root URL, you could access the example file with images/myimage.png, as in the earlier Java example.
Embedding can further complicate the access URL.
In addition to the static path you can also dynamically load servlet container resources using the forServletResource() of DownloadHandler
Image image = new Image(DownloadHandler.forServletResource("/images/myimage.png"), "My Streamed Image");Class Resources
You can use DownloadHandler to load images from the Java class path.
In this case, the images need to be below src/main/resources in the Java compilation path.
The path for forClassResource() can be either absolute considering src/main/resources as the root path and in that case you need to include the leading / or the path can be relative to the class package. For instance, if the class is com.example.ui.MyData the image can be below src/main/resources/com/example/ui
Sample code when path is absolute
Image image = new Image(DownloadHandler.forClassResource(getClass(),"/images/myimage.png"), "My Streamed Image");Sample code when path is same as the package of the class in parameter
Image image = new Image(DownloadHandler.forClassResource(MyData.class,"myimage.png"), "My Streamed Image");Icons
Icons are small graphical symbols intended to represent the various functions of an application, as well as different types of data. Vaadin has over 600 built-in icons for you to use in your applications.
You can use icons in the same way as any other components:
Most components allow you to place icons beside the title or inside the component, as a prefix, a suffix, or a helper component. The placement options depend on the component.
new tab
TextField field = new TextField("Street Address");
field.setPrefixComponent(new Icon("vaadin", "map-marker"));
field.setSuffixComponent(new Icon("vaadin", "building"));
// Wrap the icon inside a composition
HorizontalLayout helper = new HorizontalLayout();
helper.add(new Icon("vaadin", "info-circle-o"));
helper.add(new NativeLabel("Here be help"));
field.setHelperComponent(helper);
add(field);You can use either a helper component (such as an icon) or text, but not both.
If you need both, you can put them inside a compositing component, such as a HorizontalLayout, as in the example above.
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