This video was part of a series of presentations produced in anticipation of Drupal 8's official release. For information about theming based on official releases of Drupal 8, view tutorials in our Drupal 8 Theming Guide.
[# card #]
nid: 2512
title: D8 Theming series
[# endcard #]
This presentation outlines some of the major changes to the way that themes are built in Drupal 8 and is intended to help you generate a list of the things you're going to need to know in order to start making awesome Drupal 8 themes. A lot has changed, and there are a lot of new things to learn. However, one of the primary focuses has been on making the theme layer easier to understand, and easier to get started with.
Almost every aspect of the theming layer has been touched in one way or another during the Drupal 8 development cycle. We think some of the important ones to learn about are:
- How Drupal 8 makes the theme layer easier to understand
- Changes to help make Drupal responsive and mobile friendly
- The adoption of current best practices for HTML5, CSS, and JavaScript
- The addition of a new template engine based on Twig
After watching this presentation you should have a better understanding of the things you'll need to learn in order to create themes in Drupal 8 and where you might need to brush up.
Additional resources
- Drupal 8 Theming Guide (Drupalize.Me)
- Changes for themers
- Twig Theming video tutorial series
- Acquia's Ultimate Guide to Drupal 8: Episode 5 - Front-End Developer Improvements
- DrupalCorn Presentation by Marc Drummond: Building a Drupal 8 theme with new fangled awesomeness
- DrupalCon Sydney Presentation by Jen Lampton: Twig, and the New Theme Layer in Drupal 8
- DrupalCon Austin Presentation by Scott Reeves and Joël Pittet: Drupal 8 Theme System: hook_theme to Twig Template
This video was part of a series of presentations produced in anticipation of Drupal 8's official release. For information about multilingual sites based on official releases of Drupal 8, take a look at our Multilingual sites topic.
[# card #]
nid: 2925
title: Multilingual sites topic
[# endcard #]
This presentation outlines some of the major changes to the Drupal core multilingual system. A lot of features that were in contributed modules have been rolled into core, and a number of existing multilingual features have been greatly improved. There are a lot of cool new things to get up to speed with. In this video, we'll review:
- New and obsolete modules
- UI changes
- Developer changes
After watching this presentation you should have a better understanding of the things you'll need to learn to get up to speed with the new multilingual features in Drupal 8, including things to watch for on the module development and theming sides.
Additional resources
Drupal 8 Multilingual Initiative site
Gábor Hojtsy's Multilingual Changes Summary (PDF)
This presentation walks through quite a long list of major contributed modules and best practices that have been incorporated into Drupal 8 core. There are a lot of new features that you'll get out of the box, from Views to Services. In particular we'll cover:
- Exactly what best practices mean
- How core and contributed modules help the community define best practices
- List the major categories of features that have been incorporated
After watching this presentation you should have a better understanding of what best practices are, and a list of the major contributed modules from Drupal 7 that have been added, in one form or another, into Drupal 8.
YAML, which stands for YAML Ain't Markup Language, is a human-readable data serialization format that's been widely adopted in a variety of use cases in Drupal. Anyone wanting to write modules, or themes, for Drupal will need to understand YAML syntax. Even site builders are likely to encounter YAML at least in passing as YAML is the data-serialization format of choice for Drupal's configuration management system. Good thing it's pretty easy to learn even with the most basic of programming backgrounds.
This tutorial will look at the YAML data format and provide examples of how to write and read YAML. Starting with an introduction to the language's syntax and some of the strengths of YAML. Then looking at the difference between scalar data types like strings and integers, and collection data types like lists and associative arrays.
Since YAML in the Drupal world is read into PHP and ultimately becomes a PHP data structure that we can use in our own code we'll also look at how the YAML we write in a .yml file is represented in PHP data types. To do this we'll use the YAML Sandbox module that provides a handy textarea into which we can type YAML and have it parsed into PHP data structures.
Learning objectives
- Explain what YAML is and its strengths as a data serialization format
- Create scalar key/value pairs in YAML
- Create lists, and associative arrays using YAML collections
- Understand how the YAML you write is represented in PHP
Tips
- In Drupal, use the .yml extension and not .yaml
- Ensure your code editing application is configured to use spaces (preferably 2 spaces, as per Drupal coding standards), not the tab character when the TAB key is pressed. If you have tab characters in a YAML file within a Drupal environment, a fatal PHP error will be thrown and you'll see a White Screen of Death (WSOD).
- Copy and paste from an existing YAML file to ensure the formatting is correct, and edit from there.
Additional resources
- http://www.yaml.org
- YAML Sandbox module
- Find other tutorials and external resources related to YAML on our YAML topic page (Drupalize.Me)
Twig is the theme template engine in Drupal as of version 8. Like any code, there are guidelines and standards that dictate both the style and the structure of the code. In this tutorial we will explain how to adhere to the Drupal code standards while implementing Twig templating.
By the end of this tutorial you will be able to adhere to Drupal's coding standards when writing Twig, and know where to find more information about the guidelines when necessary.
You've got a slick responsive theme for your Drupal site that's been implemented in CSS using media queries. But the content and images on your site will regularly be updated and you want to use the Responsive Images module to create responsive image style field formatters that you can apply to image field display settings.
In this lesson, we'll review the concepts of breakpoints and media queries so that you can better understand what's going on when you encounter them in non-CSS file contexts like configuration forms for responsive image styles or breakpoint YAML files.
By the end of this tutorial, you should have an understanding of what breakpoints are, how they are expressed in media queries, and how they are relevant in the context of Drupal.
Some, but not all, themes come with administrator-configurable settings that you can change through the UI. These might allow you to upload your own logo, choose between a couple of different pre-defined layouts, or turn features of a theme on or off. In this tutorial we’ll look at where you can find these theme settings if they exist, and how to go about changing them.
Preprocess functions are specially-named PHP functions that allow themes and modules to modify the variables passed to a Twig template file. They are commonly used by themes to alter existing variables before they are passed to the relevant template files. For example; Changing the makeup of render array so that it renders an <ol>
list instead of a <ul>
list. Or appending data to the label of a node depending on custom logic.
In this tutorial we'll:
- Define a new preprocess function in our theme's .theme file
- Use the preprocess functions to modify the content of an existing variable before it's used in Twig
By the end of this tutorial you should be able to define new preprocess functions in a theme (or module) that manipulate the variables for a specific Twig template file.
Theme developers often need to add or remove classes and other attributes from an HTML tag. Template files handle this with a special Attributes object that contains the attributes and their values, as well as a handful of powerful methods to help manage these attributes.
In this tutorial we’ll cover:
- Adding/removing classes from elements in a Twig template
- The attributes object
- Examples of common tasks using various helper methods on the attributes object
Making Drupal fast by default implies having caching layers and CSS and JavaScript aggregation utilities enabled out-of-the-box. As a theme developer this can be annoying, because you must clear these various caches in order to preview any changes. In addition, inspecting variables with debugging tools often produces PHP errors. We'll make some recommendations for PHP settings on your local environment that can prevent these errors from happening so often.
By the end of this tutorial, you should be able to:
- Set up your local Drupal site for theme development
- Prepare your local development environment for working on and debugging themes
Core Themes: Bartik
FreeBartik is a core theme in Drupal. As a default theme for Drupal, it serves as an instructive example of a well-developed responsive theme. In this tutorial, we'll tour and explore Bartik, identify its primary features, and explain the use case for the Bartik theme and what you can learn from it.
Core Themes: Stark
FreeStark is one of the themes bundled with Drupal. It is intentionally bare bones and its purpose is to help Drupal theme and module developers get to the heart of Drupal's system templates. In this tutorial, we'll explore Stark and its primary features and discuss the various reasons for utilizing the Stark theme.
As we learned in the What Is a Breakpoints YAML file? tutorial, modules and themes can expose their site's CSS breakpoints and media queries to other Drupal modules and themes by implementing a breakpoints YAML file. In that tutorial, you also learned about the structure of a breakpoints configuration file and why you'd want to create one. In this tutorial, we’ll walk through the process of creating an example breakpoints file step-by-step.
By the end of this lesson, you should be able to create a working breakpoints YAML file in a theme or module. We'll test it out by enabling Drupal's Responsive Image module, where we'll be able to see it listed in the configuration form for creating a new responsive image style.
In Drupal's Appearance UI, all themes get a theme settings form. As a theme developer, you can customize the theme settings form, enabling site administrators to have more control over the appearance of the theme.
In this tutorial, we'll show you how to add admin-configurable settings to your theme. In the process of doing this, we'll use a variety of theme and module development skills and assume you have some familiarity with using Drupal's Form API, Configuration API, and theme system (see Prerequisites).
By the end of this tutorial, you will be able to provide custom theme settings that an administrator can use to modify the appearance of the theme.
New asset libraries can be defined by either modules or themes. In order to define a new asset library you need to create the requisite CSS and JavaScript files, and a new THEMENAME.libraries.yml, or MODULENAME.libraries.yml file that aggregates them together and provides metadata about the library itself and any dependencies.
In this tutorial we’ll:
- Look at the structure of a *.libraries.yml file and demonstrate how to combine a couple of CSS and JS files together into an asset library that can be used in a theme or a module
- Look at how one asset library can declare that it is dependent on another in order to ensure the assets from the dependency are loaded as well
By the end of this tutorial you should know how to define a new asset library in either a module or a theme.
Info files, aka THEMENAME.info.yml files, provide Drupal with metadata about your theme, the features it supports, and the regions that it defines. All themes are required to have a THEMENAME.info.yml file, and creating one is generally the first step you'll take when creating a new theme.
In this tutorial we'll:
- Create a new .info.yml file and define a new theme
- Review the required key/value pairs of an .info.yml file
- Enable our new theme in the Drupal UI
By the end of this tutorial you'll be able start a new theme by creating the required *.info.yml file and better understand its contents.
If you want to make changes to the HTML markup of any element on the page you need to first figure out the theme hook or base name of the template file used to generate it. This information is required to override the template in your custom theme.
There are other situations in which knowing the theme hook name of a template file is useful. Including determining which preprocess function affects a template, and which template theme hook suggestions can be used.
In this tutorial we'll learn:
- How to figure out the theme hook name for any template
By the end of this tutorial you should be able to use the output from Twig's debugging mode to determine the theme hook name of any template file.
When determining which template file to use to theme an element, Drupal uses the list of theme hook suggestions to look for the best match. This allows for fine-grained control over how things appear based on dynamic state and contextual information in your application. The list of theme hook suggestions varies for each base template, so we need a way to figure out our options.
In this tutorial we'll look at:
- How to determine the list of valid theme hook suggestions for any template file
- How theme hook suggestions are added by modules and themes
By the end of this tutorial you should be able to explain how theme hook suggestions are added, and determine the valid suggestions for any template file.
Drupal core comes with a few base themes: Stable, Stable 9, Classy, and Stark. Each one has a different intended use case. And all of them are useful as a reference for building your own themes.
In this tutorial we'll:
- Learn what each of the base themes included in Drupal core is intended to be used for
- Compare the output from the base themes with a focus on Stable and Classy
By the end of this tutorial you'll be able to explain the use case for each of the base themes included with Drupal core and make an informed decision about which, if any, to use when creating your own custom themes.
Anyone writing JavaScript for Drupal should use the Drupal.behaviors
API when writing their custom JavaScript functionality. Doing so ensures that your JavaScript is executed at the appropriate times during the life cycle of a page, such as when the page loads, or after new DOM elements have been added via an AJAX request.
In this tutorial we'll look at:
- The problem that
Drupal.behaviors
solves - How to use
Drupal.behaviors
when writing your JavaScript code
By the end of this tutorial you should be able to explain what the Drupal.behaviors
API is, and be able to use it in your own JavaScript.