Flutter's website

Issues, bugs, and requests

We welcome contributions and feedback on our website! Please file a request in our issue tracker and we'll take a look.

For simple changes (such as to CSS and text), you probably don't need to build this site. Often you can make changes using the GitHub UI.

If you want/need to build, read on.

Before you build this site

1. Get the prerequisites

Install the following tools if you don't have them already.

• bash, the Bourne shell. These instructions assume you're using bash -- setup might not work using other shells.
• nvm, the Node Version Manager.
• rvm, the Ruby Version Manager.
• Flutter
• Dart SDK

IMPORTANT: Follow the installation instructions for each of the tools carefully. In particular, configure your shell/environment so that the tools are available in every terminal/command window you create.

2. Clone this repo and its submodule

NOTE: This repo has a git submodule, which affects how you clone it.

To clone this repo, follow the instructions given in the GitHub help on Cloning a repository, and choose one of the following submodule-cloning techniques:

• Clone this repo and its submodule at the same, use the --recurse-submodules option:
  git clone --recurse-submodules https://github.com/flutter/website.git
• If you've already cloned this repo without its submodule, then run this command from the repo root:
  git submodule update --init --remote

IMPORTANT: Whenever you update your repo, update the submodule as well:
git pull; git submodule update --init --remote

3. Run installation scripts

NOTE: It is safe to (re-)run all of the commands and scripts given below even if you already have the required packages installed.

Open a bash terminal/command window and execute the following commands:

1. cd <path-to-this-repo>   # change to root of this repo
2. source ./tool/env-set.sh   # initialize environment variables; install/use required Node & Ruby version
3. ./tool/before-install.sh   # install core set of required tools
4. ./tool/install.sh   # install everything else needed to build this site

IMPORTANT:

• Any time you create a new terminal/command window to work on this repo, repeat steps 1 and 2 above.
• If you upgrade Dart then rerun all of the steps above.

Developing

1. Create a branch.

2. Make your changes.

3. Test your changes by serving the site locally. Run either one of these commands:

   • ./tool/serve.sh

   or

   • bundle exec jekyll serve --incremental --watch --livereload --port 4002

     Note: Unless you're editing files under site-shared, you can safely ignore ERROR: directory is already being watched messages. For details, see #1363.

4. Prior to submitting, validate site links:
   ./tool/shared/check-links.sh

TIP: Sometimes Jekyll gets confused and seems to be out-of-sync. (This might happen when you pull from master and lots of image files have moved.) To fix this, stop the serve.sh script, remove the generated site files by hand, and then restart the serve.sh script:

^C
$ rm -Rf ./_site/* ./.jekyll*
$ ./tool/serve.sh

Deploy to a staging site

You can deploy your local edits to a personal staging site as follows (steps 1 and 2 need to be done only once):

1. In the Firebase Console, create your own Firebase project (e.g. 'mit-flutter-staging')

2. Tell Firebase about that project with the firebase use command:

   $ npx firebase use --add
   ? Which project do you want to add? <select the project you created>
   ? What alias do you want to use for this project? (e.g. staging) my-foo

3. Tell Firebase that you want to deploy to staging:

   $ npx firebase use my-foo
   Now using alias staging (<your project name>)

4. Tell Firebase to deploy:

   $ ./tool/shared/deploy.sh --local my-foo
   
   === Deploying to '<your project name>'...
   
   i  deploying hosting
   i  hosting: preparing _site directory for upload...
   ✔  hosting: 213 files uploaded successfully
   i  starting release process (may take several minutes)...
   
   ✔  Deploy complete!

Deploying to the official site

Deploy to the default firebase project (hosting the official site) using this command:

./tool/shared/deploy.sh --local --robots ok default

Writing for flutter.io

(Eventually, this section should be expanded to its own page.)

Syntax highlighting

The easiest way to syntax highlight a block of code is to wrap it with triple backticks followed by the language.

Here's an example:

class ExampleWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container();
  }
}

Advanced stylization of code blocks

Do you want to highlight (make the background yellow) code inside a code block? Do you want to strike-through code inside a code block? We got that!

For syntax highlighting, plus yellow highlighting and strike-through formatting, use the prettify tag with additional custom inline markup.

If you want to highlight a specific bit of code, use the [[highlight]]highlight this text[[/highlight]] syntax with the prettify tag.

For example:

{% prettify dart %}
void main() {
  print([[highlight]]'Hello World'[[/highlight]]);
}
{% endprettify %}

If you want to strike-through a specific bit of code, use the [[strike]]highlight this text[[/strike]] syntax with the prettify tag.

For example:

{% prettify dart %}
void main() {
  print([[strike]]'Hello World'[[/strike]]);
}
{% endprettify %}

The prettify plugin will also unindent your code.

If you want to see how this functionality was added to this site, refer to this commit.

Including a region of a file

You can include a specific range of lines from a file:

{% include includelines filename=PATH start=INT count=INT %}

PATH must be inside of _include. If you are including source code, place that code into _include/code to follow our convention.

Code snippet validation

The code snippets in the markdown documentation are validated as part of the build process. Anything within a '```dart' code fence will be extracted into its own file and checked for analysis issues. Some ways to tweak that:

• If a code snippet should not be analyzed, immediately proceed it with a <!-- skip --> comment
• To include code to be analyzed, but not displayed, add that in a comment immediately proceeding the snippet (e.g., <!-- someCodeHere(); -->)
• A snippet without any import statements will have an import ('package:flutter/material.dart') automatically added to it
• We ignore special formatting tags like [[highlight]].

Updating the Sample Catalog

The sample catalog's markdown files are generated by running sample_page.dart from the Flutter github repo. Starting from the root of the Flutter repo:

cd examples/catalog
dart bin/sample_page.dart '<commit hashcode here>'
cp examples/catalog/.generated/*.md <your website repo>/catalog/samples

The generated markdown files will contain cloud storage links for sample app screenshots. Screenshots for each sample app are automatically generated for each Flutter repo commit. Choose a recent commit hashcode and confirm that the screenshots look OK.

If new sample apps have been added, update _data/catalog/widget.json. The entry for each widget class that's featured in a sample app should contain "sample" line like:

"sample": "ListView_index",

The sample_page.dart app will print a list of all of the "sample" properties that should appear in the widget.json file.