Jean-Luc Makiola
809013997d
Both home-screen widgets kept highlighting yesterday as "today" after the date changed — and the agenda kept dimming events against yesterday — until the user paged the month arrows or removed and re-added the widget. The data layer was never the problem: the month cache guard already drops its window as soon as the anchor date differs, which is exactly why an arrow tap fixed it instantly. What was missing was anything to *trigger* a redraw at the day boundary. The manifest asked for DATE_CHANGED and the receiver's KDoc presented it as the rollover mechanism, but DATE_CHANGED is not on the implicit-broadcast exemption list, so a manifest-declared receiver has not been given it since Android 8 — this has never worked on any device the app supports. That left only updatePeriodMillis, which the system defers in doze and OxygenOS-style skins throttle harder still; the reporter's is a 30-minute backstop that in practice never ran. So the app now holds its own wake-up. WidgetRolloverScheduler arms a single alarm for just after the next local midnight and every firing re-arms the next, the same shape as ReminderAlarmScheduler. It is deliberately inexact: setAndAllowWhileIdle needs no permission and survives doze, and a rollover a few minutes late is invisible on a sleeping screen — exact alarms stay reserved for reminder snooze. The target is the *actual* start of the day rather than a literal 00:00, so it stays right in Havana, where DST means midnight does not happen, and it walks on past a whole date skipped by a date-line move. The alarm is only armed while a widget is actually placed: onEnabled/onDisabled on both Glance receivers re-sync it, and sync() cancels only when neither kind is left, so removing the month widget never stops the agenda one rolling over. WidgetUpdateReceiver re-arms on everything that can invalidate the alarm — boot and package-replace wipe it, a clock or timezone change moves the boundary it was aimed at — and CalendulaApp does the same on start, which is what arms existing installs that upgrade into this without re-adding their widget. It also gained an action allowlist, matching ReminderScheduleReceiver: it is exported and the broadcasts it takes are protected. DATE_CHANGED stays in the filter as a free extra for any OEM that does deliver it, but the docs no longer claim anything depends on it. Adding the two overrides makes the receivers as structurally alike as the widgets they wrap, which is how #89 collapsed Glance's provider map, so the keep rule now covers GlanceAppWidgetReceiver as well. Verified in the releaseTest mapping: all four classes keep their real names. Tests cover the arithmetic that decides when to wake — ordinary days, the re-arming instant itself, both DST transitions, a zone whose midnight does not exist, a half-hour offset, and the same instant seen from two zones. Closes #228.
Calendula
A modern Material 3 Expressive calendar for Android.
Reads, writes, and reminds — on top of the system calendar, with zero network access.
Calendula is named after the flower whose name — like the word calendar —
comes from the Latin kalendae, the first day of the month. It lives
entirely on top of Android's CalendarContract: any calendar synced to your
device (CalDAV via DAVx5, Google, local, WebCal subscriptions, …) simply
appears, and everything you create or edit syncs back the same way. No own
database, no sync stack reinvented.
✨ Features
Calendar
- Month, week, and day views with a one-tap view switcher
- Full event details — attendees and their responses, reminders, recurrence (humanized), availability, visibility, foreign time zones
- Per-calendar visibility toggle, grouped by account
Editing
- Create, edit, and delete events — including recurring events with scoped writes: only this event, this and all following, or the whole series
- Recurrence picker with one-tap presets and custom rules (interval, weekday toggles, end conditions); rules it can't express are preserved verbatim
- Conflict-safe saves: if an event changed elsewhere while you were editing, Calendula asks instead of silently overwriting
- Read-only calendars (WebCal, birthdays) are detected and respected
Reminders
- Event reminders delivered by Calendula itself as notifications — essential when it's your only calendar app, since Android delegates reminder delivery to calendar apps
- Tap a reminder to land on the event
Design & privacy
- Real Material 3 Expressive throughout — dynamic color (Android 12+), expressive motion and shapes, light/dark theme
- English and German UI plus community translations (Spanish, French, Italian, Polish, and more in progress), per-app language setting — and open to more languages
- Zero telemetry, zero analytics, no internet permission — your data never leaves the device
📦 Install
Pick whichever channel you already use — they all install the same app:
| Channel | Updates | Notes |
|---|---|---|
| Official F-Droid | On F-Droid's build schedule | Recommended; no extra setup |
| Self-hosted F-Droid repo | Minutes after a release | Fastest; needs the repo added once |
| Codeberg release / Obtainium | Per release | Plain APK download, or automated by Obtainium |
| Google Play | Per release | Signed with Google's key — see below |
| Build from source | Whenever you build | Full control |
F-Droid (recommended)
Calendula is on the official F-Droid repository — just search for Calendula in any F-Droid client, or install it from f-droid.org.
F-Droid rebuilds from source on its own schedule, so a new version usually shows up there a few days after release.
Self-hosted F-Droid repo (fastest updates)
Every release is built, signed, and published to a self-hosted F-Droid repository as part of the release pipeline, so it lands there first. Add it once and your F-Droid client handles updates from then on:
-
In your F-Droid client, open Settings → Repositories → Add (or open the link below on your phone):
https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo?fingerprint=C2C0640402BF458FC0ED957AF0B37AA4C14022E72F89CE90B5965B458CF73425Repo:
https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo· fingerprint (SHA-256):C2C0 6404 02BF 458F C0ED 957A F0B3 7AA4 C140 22E7 2F89 CE90 B596 5B45 8CF7 3425 -
Refresh, search for Calendula, install.
Codeberg release / Obtainium
If you'd rather not use F-Droid at all, every release is also published on
Codeberg with the
signed APK (calendula_vX.Y.Z.apk) and a .sha256 checksum attached — download
and install it directly.
For automatic updates from that channel, use
Obtainium — on the phone,
add Calendula in one tap,
or do it by hand: Add App → paste https://codeberg.org/jlmakiola/calendula
→ Add. Either way, Obtainium tracks the releases and prompts you when a new
one appears.
Google Play
Calendula is live on Google Play: play.google.com/store/apps/details?id=de.jeanlucmakiola.calendula.
Play builds are signed with Google's key rather than mine, so switching between Play and any other channel requires an uninstall (and with it, a fresh start for app settings — your events live in the system calendar and are unaffected).
Build from source
The build is a plain Gradle build with no proprietary dependencies — see
docs/BUILDING.md (note the floret-kit submodule).
Official F-Droid, the self-hosted repo, and the Codeberg releases all share the same signing key, so you can switch freely between them without reinstalling. Google Play is the exception — see above.
📚 Documentation
- Contributing — how to report, propose, and patch
- Building from source — requirements and Gradle tasks
- Architecture — the layered design and key pipelines
- Milestones — what's shipped and what's next
🤝 Contributing
Bug reports, ideas, and patches are all welcome on Codeberg.
The short version: start with an issue. Features get a yes-or-no before they
get code, and both features and bugs are assigned a milestone whose
release/vX.Y.Z branch your pull request then targets. Typo and docs fixes can
skip straight to a pull request. Translations don't go through pull requests at
all — Weblate owns them.
Read CONTRIBUTING.md before writing code: it covers the
workflow, the build (note the floret-kit submodule), and the architectural
rules a change is reviewed against.
🌍 Translations
Calendula ships in English and German, with community translations in Arabic, Chinese, French, Italian, Polish, Portuguese, Russian, and Spanish at varying degrees of completeness — partial is fine, untranslated strings simply fall back to English. You're warmly invited to add or finish your language. Translations are managed on a self-hosted Weblate:
No coding needed — register on the Weblate server, pick (or request) a language, and translate the strings in your browser. You can also reach this link in the app from the top of Settings → App language.
📜 License
MIT — Jean-Luc Makiola, 2026