Most web applications delegate to Cascading Style Sheets (CSS) the stylistic details of the page – fonts, colors, margins, borders and alignment. This helps the remaining HTML to remain simple and semantic, which usually makes it easier to read and maintain.
Tapestry includes sophisticated support for CSS in the form of annotation-based linking, far-future expire headers, automatic duplicate removal, and other features provided for assets.
Default style sheet
Tapestry 5.5.0 and later also includes Bootstrap 4.3.1. To use it, just add @ImportModule(Bootstrap4Module.class) to your application's module class (normal AppModule.java):
Tapestry 5.5.0 and later also allows you to have Tapestry not provide any CSS at all. To do that, just add @ImportModule(NoBootstrapModule.class) to your module class. In this case, you'll need to set the tapestry.default-stylesheet (SymbolConstants#DEFAULT_STYLESHEET) configuration symbol to tell Tapestry what's your main CSS file. Otherwise, an exception will be thrown and the webapp won't start.
Adding your own CSS
A page or component (for example, a layout component) that is rendering the <head> tag can add a style sheet directly in the markup.
If you want to leverage Tapestry's localization support, you may want to make use of an expansion and the "asset:" or "context:" binding prefix:
The "context:" prefix means that the remainder of the expansion is a path to a context asset, a resource in the web application root (
src/main/webapp in your workspace). By contrast, the "asset:" prefix tells Tapestry to look in the class path. See CSS.
Using the @Import annotation
Another approach to adding a style sheet is to include an @Import annotation (starting with Tapestry 5.2) on your component class:
(For Tapestry 5.0 and 5.1, use the deprecated @IncludeStyleSheet annotation instead.)
Conditionally loading IE-only style sheets
For Tapestry 5.2 and later, if you need to load a different style sheet for Internet Explorer browsers, or for certain versions of IE browsers, you can use Tapestry's built-in support for IE conditional comments. Just add something like the following to your page or component (or layout) class:
The above will render something like:
Naturally, the conditional part can be any other IE conditional expression, such as "lt IE 8".
Suppressing the default style sheet (Tapestry 5.3 and earlier)
Though it should be rarely needed, you can prevent Tapestry's default style sheet from loading by overriding the configuration in your application's module (normally AppModule.java):
Note: In Tapestry 5.3 and later, the misspelled "InjectDefaultStyleheet" is corrected to "InjectDefaultStylesheet".
Overriding Bootstrap (Tapestry 5.4 and later)
The SymbolConstants.BOOTSTRAP_ROOT ("tapestry.bootstrap-root") symbol tells Tapestry where the Bootstrap CSS file is. You can override that symbol (see CSS) to have it point to your own version of Bootstrap (or even to an empty file if you want to eliminate Bootstrap entirely).
For the above, your bootstrap.css file would be in your app's META-INF/assets/css folder.