Material Clock

! This project is currently in beta expect a lot of bugs

A Material 3 Expressive clock app for Android, built entirely in Jetpack Compose. It has alarms, a world clock, timers and a stopwatch, plus a home-screen analog clock widget you can reshape.

It is based on rbouaf/material-clock, so huge thanks to him.

Features

Alarms

• One-shot or repeating alarms with a custom label, per-alarm ringtone and vibration
• Pick which days repeat, with a configurable week start (system default, Saturday, Sunday or Monday)
• Snooze (default 10 min) and auto-silence (default 10 min, or never)
• Rings over the lock screen with a full-screen Snooze / Dismiss screen
• Rearmed automatically after a reboot, time change or timezone change
• Handles "set an alarm for…" requests from Assistant and other apps

World clock

• Add cities by searching real IANA time zones, so daylight saving is handled by the platform
• Shows the offset from your home zone, including half- and quarter-hour zones
• Rows invert at night; optional seconds and 12/24-hour override

Timers

• Multiple labelled countdowns with start, pause and resume
• Stored as deadlines, so they stay accurate if the app is killed
• Live notification you can control from the shade, with its own sound and vibration

Stopwatch

• Hundredths-of-a-second display with laps
• Highlights the fastest and slowest lap
• Runs on elapsed-realtime, so changing the clock or crossing a DST change can't move it

Clock widget

• An analog clock you can shape: circle, squircle, rounded square, flower and more
• Five presets (Classic, Bare, Roman, Railway, Bloom) or a fully custom face
• Eleven hand styles, several numeral systems (including Roman and Eastern Arabic), tick and index options, optional date and a seconds hand
• Follows the app's colours or its own palette

Theming

• Dynamic colour from your wallpaper on Android 12+, with static fallbacks
• Eleven Expressive palettes (Baseline, Expressive, Concept, Violet, Coral, Ember, Citron, Forest, Lagoon, Azure, Fuchsia)
• System, light or dark mode, plus an AMOLED black option
• Google Sans Flex variable font

Privacy

• No accounts, no analytics, no crash reporting, no ad IDs
• No INTERNET permission, so Android itself prevents the app from using the network
• Alarms, timers, cities and settings are stored in the app's private storage

Permission	Why
USE_EXACT_ALARM (SCHEDULE_EXACT_ALARM up to API 32)	Ring at the exact minute you set
POST_NOTIFICATIONS	Ringing alarm and live timer/stopwatch notifications
USE_FULL_SCREEN_INTENT	Show the alarm over a locked screen
RECEIVE_BOOT_COMPLETED	Re-arm alarms after a reboot
FOREGROUND_SERVICE (media playback)	Keep alarm audio playing while it rings
VIBRATE, WAKE_LOCK	Vibration and keeping the screen on while ringing

Requirements

• Android 8.0 (API 26) or newer
• Dynamic colour needs Android 12 (API 31) or newer; older versions use the built-in palettes

Building

You'll need Android Studio with JDK 17. The project uses Android Gradle Plugin 9.2, Kotlin 2.4 and compileSdk 37.

git clone https://github.com/breadworkz/Clock.git
cd Clock
./gradlew assembleDebug

The debug build installs alongside a release build (application ID app.materialclock.debug). The APK ends up in app/build/outputs/apk/debug/.

Material 3 Expressive components currently require the alpha Compose BOM (compose-bom-alpha) and material3 1.5.0 alpha, which are pinned in gradle/libs.versions.toml.

Release builds

./gradlew assembleRelease produces a minified, resource-shrunk APK. To sign it with your own key, add these to ~/.gradle/gradle.properties (not the project's):

clockStoreFile=/path/to/keystore.jks
clockStorePassword=...
clockKeyAlias=...
clockKeyPassword=...

Without them the release build falls back to the debug key. That is fine for sideloading a personal build, but not for distribution.

Project structure

app/src/main/java/app/materialclock/
├── alarm/    Alarm and timer scheduling, ringing service and screen, notifications
├── core/     Models: Alarm, WorldCity, ClockTimer, Stopwatch
├── data/     DataStore-backed settings, widget configuration and presets
├── ui/       Compose app shell, screens, sheets and theme (palettes, type, clock face)
└── widget/   Home-screen widget provider, config screen and canvas renderers
tools/        Scripts that generate the palettes and the bundled font subsets
licenses/     Third-party licence texts (SIL OFL 1.1)

Regenerating the palettes (tools/gen_palettes.py) needs pip install materialyoucolor.

Built with

• Kotlin and Jetpack Compose
• Material 3 Expressive (androidx.compose.material3)
• AndroidX DataStore, Lifecycle and androidx.graphics.shapes

Credits

• rbouaf/material-clock, which this app is based on
• Google Sans Flex (© Google LLC) and Noto Sans Arabic (© The Noto Project Authors), used under the SIL Open Font License 1.1

Google, Google Sans, Material, Android and Pixel are trademarks of Google LLC. This app is not affiliated with or endorsed by Google.

License

Released under the GNU General Public License v3.0. The bundled fonts keep their own licences (see above).