The frontend of this project is a Flutter application designed to run on both Android and iOS devices (and possibly as a PWA). The frontend is responsible for displaying the user interface and handling user input. It communicates with the backend via a REST-api to retrieve and send data.

Getting Started

The flutter application is divided into multiple chunks of code.

the lib directory contains the main code of the application.
the android and ios directories contain platform-specific code.
the root directory contains configuration files and metadata.

To run the application, you need to have the Flutter SDK installed. You can find instructions on how to do this here.

Once you have the Flutter SDK installed, you can locally install the dependencies by running:

flutter pub get

Development

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Icons and logos

The application uses a custom launcher icon and splash screen. These are managed platform-independently using the flutter_launcher_icons package.

To update the icons, change the flutter_launcher_icons.yaml configuration file. Especially the image_path is relevant. Then run

dart run flutter_launcher_icons

Deploying a new version

To truly deploy a new version of the application, i.e. to the official app stores, a special CI step is required. This listens for new tags. To create a new tag position yourself on the main branch and run

git tag -a v<name> -m "Release <name>"
git push origin v<name>

We adhere to the Semantic Versioning standard, so the tag should be of the form v0.1.8 for example.

Fastlane - in depth

The application is deployed to the Google Play Store and the Apple App Store using fastlane: https://docs.fastlane.tools/

Fastlane is installed as a Ruby gem. Since the bundler-gemfile is scoped to a single directory, a Gemfile is included in both the android and ios directories. Once installed, the usage is

cd frontend/android # or ios
bundle install
bundle exec fastlane <lane>

This is reused in the CI/CD pipeline to automate the deployment process.

Fastlane assumes mutliple secrets to be present as files in the platform directories. These are:

for android:
- secrets.properties used by gradle to load secrets needed at execution time
- release.keystore used by gradle to sign the apk
- google-key.json used by fastlane to authenticate with the Google Play Store
for ios:
- TODO

These files are stored as secrets in the GitHub repository so that the CI pipeline can access them.