Contributing to Sky Map

First off, thank you for considering contributing to Sky Map! It's a labor of love maintained in our spare time by a couple of ex-Googlers here in Pittsburgh, and community contributions help keep it alive. However...

We are not accepting most PRs at the moment.

Why? We're in the midst of a major rewrite and adding more features will just move the goalposts! When this is complete we'll gladly accept help.

Before You Start

Please email us (or file a feature request) before embarking on any major changes or feature additions. We may have a different vision for the direction of the app and it would be a pity to do work that we can't accept and would be wasted.

Bug fixes, dependency upgrades, and translation contributions are generally welcome without prior discussion.

A Note on Response Times

It is likely we'll be slow to respond to emails and PR requests. Depending on what else is going on it might be days, it might be months. I do apologize for that — life is busy. Sometimes the reply might be simply to point you at this documentation, which will seem very ungrateful and unfriendly.

Thanks for your contributions! They're definitely appreciated even if our slowness to respond might make it seem otherwise.

Types of Contributions

Despite the temporary moratorium on new features, we're always grateful for:

• Bug fixes — Simple, focused, few line fixes are very easy for us to approve.
• Dependency upgrades — Keeping things up to date is always welcome.
• Translations — We're particularly grateful for fixed or new translations since we've lost the 100% coverage of non-English languages that we once had.
• Documentation — Improvements to docs, README, comments, etc.
• Feature additions — Please email us first (see above).

Pro-tip: Small, focused PRs are easier for us to approve! If your PR does too much it might get stalled because even if 90% of it is welcome there might be 10% that we're not happy with. So keep them small if you can. Plus, we'll be able to review them faster.

Development Setup

Prerequisites

• Android Studio (latest stable recommended)
• Android SDK (API level 26–35)
• Java 17 toolchain
• A local.properties file in the project root containing:

sdk.dir=<path to your Android SDK>

Android Studio can create this file for you.

Project Structure

You should see the following directories (from within the stardroid-v1 directory):

• app/ — Application source
• datamodel/ — Protocol buffer definitions for astronomical objects
• tools/ — Source for generating binary data used by the app

See docs/ARCHITECTURE.md for a detailed architecture overview.

Building

All commands below should be run from within the stardroid-v1 directory:

Quick Build (Debug APK)

./gradlew :app:assembleGmsDebug

The APK can be found in app/build/outputs/apk/.

Quick Build (Default)

./build.sh             # GMS release
./build.sh --fdroid    # F-Droid release
./build.sh -d          # GMS debug

Full Build (Including Data Generation)

./build.sh --full             # GMS including data generation
./build.sh --full --fdroid    # F-Droid including data generation

Use --full when modifying star catalog or astronomical data.

Build Flavors

• gms — Includes Google Play Services (Analytics, Location)
• fdroid — Pure open source, no Google dependencies

Always specify the flavor when building: assembleGmsDebug not assembleDebug.

Building a Release APK

Note: Sky Map team only

Create a file in the app directory called no-checkin.properties with appropriate values:

store-pwd=
key-pwd=
analytics-key=

and overwrite google-services.json with the correct file. Then:

./gradlew :app:assembleGms

Running Tests

Unit Tests

./gradlew :app:test

Instrumented Tests

Requires a connected device or emulator:

./gradlew :app:connectedAndroidTest

Deploying to a Device

Plug your phone in and run:

./deploy.sh       # Release build
./deploy.sh -d    # Debug build
./undeploy.sh     # Remove the app

Submitting Changes

1. Fork the repository and create a branch from master.
2. Make your changes, keeping commits focused and atomic.
3. Run the unit tests to make sure you didn't break anything.
4. If you have multiple commits, please combine them into one by squashing.
5. Open a Pull Request with a clear description of what you changed and why.

Coding Style

We follow the Google Java Style Guide (or try to):

• 100 character line wrap
• Do not prefix member variables with m (unlike common Android convention)
• Java 17 toolchain features are available

Translations

Translation files live under app/src/main/res/values-<language>/. If you'd like to contribute a new translation or fix an existing one, those PRs are very welcome. See the existing language directories for the format.

Deploying to the Google Play Store

Note: Sky Map team only

We use fastlane to manage updates to the Play Store. Available commands can be seen by running:

bundle exec fastlane

or by reading fastlane/README.md.

Before deploying a new release you will most likely want to update the whatsnew text and the list of contributors. Both these tasks can be done by Claude - see the Claude skills under .claude/.