mobile_app

The MBTA mobile app.

Project Setup

This project uses Kotlin Multiplatform Mobile (KMM). Native application code can be found in the iosApp and androidApp directories. Common code is within the shared directory.

Prerequisites

Install the tools specified in .tool-versions. You can use asdf to help manage the required versions.

Install direnv if you don't already have it, copy .envrc.example to .envrc, populate any required values, then run direnv allow.

Install and set up the GitHub CLI.

For Android development, brew install librsvg.

For iOS development, brew install swiftlint.

External Dependencies

Mapbox - docs

We use mapbox for custom interactive maps.

ios - guide - docs - keys

Mapbox requires 2 keys - a private key for installing the library and a public key for rendering map tiles. Follow the above keys link for instructions on how to configure the secret key. The public key is fetched dynamically from the backend. Be sure to follow the Firebase App Check instructions for access to the protected endpoint while developing locally.

android - guide - docs - keys

Like on iOS, Mapbox for Android requires two keys. Follow the above keys link for instructions on how to configure the secret and public key.

Note: The property name in ~/.gradle/gradle.properties is MAPBOX_SECRET_TOKEN, not MAPBOX_DOWNLOADS_TOKEN as used in the Mapbox documentation. Also, the public token should be stored in androidApp/src/main/res/values/secrets.xml, which will be created with a placeholder value if it does not already exist at build time.

Sentry - docs - keys

Sentry is used for error logging and aggregation.

Editor

The recommendation for KMM projects is to use Android Studio for editing & running the android app or shared code and XCode for only editing & running the ios app. See this KMM guide for installation instructions.

Gotchas

• Be sure to install the Android SDK Command-line Tools via Android Studio > Settings Android SDK > SDK Tool Tabs > Android SDK Command Line Tools.
• If you're seeing the error "undefined method 'map' for nil:NilClass" when running pod installs locally, you likely need to run bundle exec gem uninstall ffi then bundle install to get a cocoapods requirement to be installed properly on M1 Macs.

Running Locally

iOS

The shared library dependency is managed using Cocoapods. To install the dependency and build the ios app:

• Run a gradle sync of the project from Android Studio, or you may run ./gradlew :shared:generateDummyFramework from the root directory
• bundle install to install cocoapods and fastlane
• bundle exec pod install from within the iosApp directory.
• Open the project from /iosApp/iosApp.xcworkspace in Xcode (not iosApp.xcodeproj).
• Populate any configuration needed in your the .envrc file. These will be read by a build phase script and set as info.plist values so that they can be read by the application.

Android

To switch between the staging and prod app flavors, go to Build > Select Build Variant and then set the :androidApp Active Build Variant.

Running Tests

Unit Tests

ios

Run from XCode by navigating to Product > Test or using the test navigator. We use ViewInspector to write unit tests for SwiftUI views.

android & shared

Run within Android Studio, or by running the commands ./gradlew androidApp:check ./gradlew shared:check

Integration Tests

Team Conventions

Editing Code

• Create each new feature in its own branch named with the following naming format: initials-description (for example, Jane Smith writing a search function might create a branch called js-search-function).
• This repo uses pre-commit hooks, which will automatically run and update files before committing. Install with brew install pre-commit and set up the git hook scripts by running pre-commit install.
• Use meaningfully descriptive commit messages to help reviewers understand the changes. Consider following Conventional Commits guidelines.

Code Review

All new features are required to be reviewed by a team member. Department-wide code review practices can be found here.

Some specifics for this repo:

• Follow Conventional Commits for pull request titles.
• New pull requests will automatically kick off testing and request a review from the mobile-app team. If you aren't yet ready for a review, create a draft PR first.
• When adding commits after an initial review has been performed, avoid force-pushing to help reviewers follow the updated changes.
• Once a PR has been approved and all outstanding comments acknowledged, squash merge it to the main branch.

CI

iOS

XCode Cloud workflows are triggered on changes to the following directories:

• /iosApp
• /shared/common*
• /shared/src/ios*

If files are changed outside of those target directories but a new workflow run is reason, you can manually trigger a run through the XCode Cloud UI.

If new files or directories need to be added to the list of triggers, be sure to update the list for each relevant XCode Cloud workflow

Deploying

Development Deploys

Merging to main will automatically kick off deploys that are visible for internal testing (TestFlight for ios, internal track for android).

To upload the code signing key if it needs to be updated (which is unlikely):

aws secretsmanager put-secret-value --secret-id mobile-app-android-upload-key --secret-binary fileb://upload-keystore.jks
cat key.properties | grep storePassword | cut -f2 -d= | tr -d '\n' > passphrase.txt
aws secretsmanager put-secret-value --secret-id mobile-app-android-upload-key-passphrase --secret-string file://passphrase.txt
shred --remove passphrase.txt

To download the code signing key if you need it locally (which is unlikely):

aws secretsmanager get-secret-value --secret-id mobile-app-android-upload-key --output json | jq -r '.SecretBinary' | base64 --decode > /path/to/upload-keystore.jks
aws secretsmanager get-secret-value --secret-id mobile-app-android-upload-key-passphrase --output json | jq -r '"storePassword=\(.SecretString)"' >> /path/to/key.properties

Production Deploys

Pushing a new tag will automatically deploy to the internal testing group (on iOS), and then release notes can be added and the build can be more widely published manually.

The tag should match the version exactly - no v prefix - and the version needs to be set beforehand in iosApp/iosApp/Info.plist.

Android production deploys aren't set up yet.