Jean-Luc Makiolaandmakiolaj 0f75d2638b
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Show events at their real time on days the clocks change (#387) (#393)
On the day the clocks change, the day, 3-day and week views placed events by the time elapsed since midnight, so every event after the change sat an hour off. A 14:45 event on 25 October showed at 15:45. Blocks are now placed by wall clock.

When the clocks go back, 02:00 to 03:00 happens twice, and a wall-clock time alone can't say which of the two it means. This branch keeps track of it:

- The event form holds each time as a `FormTime`, the wall clock plus its UTC offset when that time is in the repeated hour. Validation and saving read the real instants from it, so a span ending in the repeated hour is valid and switching between the two passes is saved.
- A time picked in the form or dragged with a resize handle goes back to the event's original pass when it's set back to its original time. Otherwise it moves in the direction it was moved, stays after the start, and takes a pass the grid can draw where it was dropped.
- A drop onto a repeated time lands on the first pass, unless the event was already on the second.
- A block that runs into the repeated hour from before it is drawn to 03:00, and its label shows its real end.
- The editor, the event details and the pinned zone's "local time" line add the zone abbreviation (CEST or CET) to a time in the repeated hour.
- A recurring series that starts in the repeated hour keeps its pass when it's edited.

Also in this PR:

- `ZoneSource`, provided through Hilt, gives the timeline, the event form and reschedules the device zone. The timeline lays its pages out again when the zone changes.
- A drafted block (#153) opens the form at its exact start and end.
- A day move onto the spring-forward day keeps its wall-clock start, so moving a weekly series there is still offered for all events.

## Testing

The 1,258 unit tests pass. The instrumented suite has the same two failures as `release/v2.23.0` (`CalendarRepositorySmokeTest` and `PermissionScreenTest`), so nothing new.

I also checked it by hand on an emulator in Europe/Berlin, with the clock moved to each DST day:

- 25 October: the event from the issue (14:45, Europe/Brussels) is drawn at 14:45. A run from 02:10 CEST to 02:20 CET is drawn to 03:00 and labelled with its real end.
- Pulling the end of a 02:30 to 03:30 CET event up to 02:45 saves 02:45 CET, after its start.
- Pulling the end of a 01:00 CEST to 04:00 CET event up to 02:15 saves 02:15 CEST, and the block stays where it was dropped.
- 29 March: a 01:00 to 04:00 run and a 14:00 event both sit at their own times.

Picking times in the form and moving a series in the month view are covered by unit tests only.

Closes #387

Co-authored-by: Jean-Luc Makiola <business@jeanlucmakiola.de>
Reviewed-on: https://codeberg.org/jlmakiola/calendula/pulls/393
2026-10-14 15:54:14 +02:00
2026-10-01 16:21:11 +02:00
2026-10-07 20:22:50 +02:00
2026-10-01 16:21:11 +02:00
2026-10-07 09:56:00 +02:00
2026-09-02 12:44:40 +02:00
2026-10-01 16:21:11 +02:00
2026-10-07 09:56:00 +02:00
2026-10-07 09:56:00 +02:00

Calendula icon

Calendula

A Material 3 Expressive calendar for Android.
It works on top of the system calendar and has no network access.

CI Android 10+ Kotlin + Compose Material 3 Expressive MIT License

Get it on F-Droid   Get it on Google Play   Get it on Obtainium   Support me on Ko-fi

Week view  Month view  Agenda view  Event detail  Editing a recurring event  Calendars from your accounts  Dark theme

Calendula is named after the flower. Both its name and the word calendar come from the Latin kalendae, the first day of the month.

The app works directly on Android's CalendarContract. Any calendar synced to your device (CalDAV via DAVx5, Google, local, WebCal subscriptions) shows up in Calendula, and whatever you create or edit syncs back the same way. Calendula has no database or sync code of its own.

Features

Calendar

  • Month, week and day views, with a switcher in the top bar
  • Event details with attendees and their responses, reminders, recurrence in plain words, availability, visibility and foreign time zones
  • Calendars can be shown or hidden one by one, grouped by account
  • Your contacts' birthdays, anniversaries and other dates, if you turn it on. Contacts are read on the device and never changed.

Editing

  • Create, edit and delete events. For a recurring event you choose whether a change applies to only this event, this and all following, or the whole series.
  • The repeat picker has presets and custom rules (interval, weekdays, end condition). Rules it can't show are kept as they are.
  • If an event changed elsewhere while you were editing it, Calendula asks before saving over it.
  • Read-only calendars such as WebCal subscriptions and birthdays are detected and can't be edited by accident.

Reminders

  • Calendula shows event reminders as notifications itself. Android leaves reminder delivery to calendar apps, so if Calendula is your only one, this is where your reminders come from.
  • Tapping a reminder opens the event.

Design and privacy

  • Material 3 Expressive throughout, with dynamic color on Android 12+, light and dark themes, and expressive motion and shapes
  • Available in 16 languages, with a per-app language setting. Help translate.
  • No telemetry, no analytics and no internet permission. Your data stays on the device.

Install

All channels 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; add the repo once
Codeberg release / Obtainium Per release Plain APK download, or automatic with Obtainium
Google Play Per release Signed with Google's key, see below
Build from source Whenever you build Full control

Calendula is in the official F-Droid repository. Search for Calendula in any F-Droid client, or install it from f-droid.org.

F-Droid builds 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)

The release pipeline builds, signs and publishes every release to a self-hosted F-Droid repository, so new versions land there first. Add it once and your F-Droid client handles updates from then on:

  1. 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=C2C0640402BF458FC0ED957AF0B37AA4C14022E72F89CE90B5965B458CF73425
    

    Repo: 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

  2. Refresh, search for Calendula and install it.

Codeberg release / Obtainium

Every release is also on Codeberg with the signed APK (calendula_vX.Y.Z.apk) and a .sha256 checksum. Download it and install it directly.

For automatic updates from Codeberg, use Obtainium. On your phone, add Calendula in one tap, or add it by hand: Add App, paste https://codeberg.org/jlmakiola/calendula, then Add. Obtainium then watches the releases and tells you when a new one is out. Betas of upcoming versions are published there too, as pre-releases; to test them, switch on Include prereleases for Calendula in Obtainium.

Google Play

Calendula is on Google Play.

Play builds are signed with Google's key rather than mine, so switching between Play and any other channel means uninstalling first. You lose the app settings. Your events live in the system calendar and aren't affected.

Build from source

It's a plain Gradle build with no proprietary dependencies. See docs/BUILDING.md, and note the floret-kit submodule.

Official F-Droid, the self-hosted repo and the Codeberg releases share the same signing key, so you can switch between them without reinstalling. Google Play is the exception (see above).

Documentation

Contributing

Bug reports, ideas and patches are welcome on Codeberg.

Start with an issue. A feature gets a yes or no before anyone writes code, and features and bugs are assigned a milestone whose release/vX.Y.Z branch your pull request targets. Typo and docs fixes can go straight to a pull request. Translations go through Weblate, not pull requests.

Read CONTRIBUTING.md before writing code. It covers the workflow, the build (including the floret-kit submodule) and the architectural rules changes are reviewed against.

Translations

Calendula is written in English. Translators on Weblate have added Arabic, Belarusian, Chinese (Simplified), Czech, French, German, Hungarian, Italian, Japanese, Polish, Portuguese (Portugal and Brazil), Russian, Slovak and Spanish, some of them partly. Untranslated strings fall back to English, so a partial translation is fine. Translations are managed on a self-hosted Weblate:

Help translate Calendula

You don't need to code. Register on the Weblate server, pick a language (or request one) and translate in your browser. The app links here from the top of Settings → App language.

Privacy

Calendula has no analytics, tracking, ads, crash-reporting SDK or third-party services. It doesn't have the internet permission, so it can't send anything anywhere. Your events stay in Android's own calendar store.

Privacy policy, written in docs/PRIVACY.md, which is what that page renders.

License

MIT, Jean-Luc Makiola, 2026

S
Description
Build infrastructure only — canonical repo: https://codeberg.org/jlmakiola/calendula
Readme MIT
17 MiB
v2.22.5
Latest
2026-10-07 18:37:06 +00:00
Languages
Kotlin 98.5%
Shell 0.9%
Python 0.5%
Ruby 0.1%