Calendula

A modern Material 3 Expressive calendar app for Android.

Calendula is named after the flower of the same name, whose name comes from the Latin kalendae — the first day of the month — the same root as the word "calendar". Calendula reads from Android's built-in CalendarContract, so any calendar source synced to your device (CalDAV via DAVx5, Google, local, WebCal subscriptions, ...) is shown.

Features (V1)

• Month, Week, and Day views
• Read-only event details (write support comes in V2)
• Multi-calendar visibility toggle
• Material You Dynamic Color (Android 12+)
• Light/Dark theme follows system
• German + English UI

Building

Requires Android SDK 36 and JDK 17. The Gradle wrapper is checked in, so no host Gradle install is needed:

# Build debug APK
./gradlew assembleDebug

# Run unit tests
./gradlew test

# Run lint
./gradlew lint

If your default JDK is something other than 17, set JAVA_HOME explicitly:

JAVA_HOME=/path/to/jdk-17 ./gradlew assembleDebug

License

MIT — Jean-Luc Makiola, 2026