I am looking for a recommendation for an Android calendar app that includes some essential features.

The catch is that I need it to work with offline calendars. Offline calendars are Android calendars that are not synced with Google. They are often called local calendars.

Here are the only features that are required (more advanced features are welcome, but this is all I need):

  1. Can add/edit/delete calendar events, including repeating ones.
  2. Can delete and edit individual events in a repeated series.
  3. Can edit or delete all the remaining events in a series without affecting prior events.
  4. Is not plagued by bugs.

Seems simple, right?

That's what I thought too, but I have not found anything, so I've added a bounty to this question in hopes of getting some recommendations.

Whatever app I use, I need to be able to successfully backup and restore the calendar offline. That can be done within the app itself, or by using an additional app such as Calendar Import / Export.

Although gratis and open-source software are always preferred, neither is a requirement. KitKat compatibility, on the other hand, is a requirement.

So far, I have spent hours trying all the following apps, and none of them have this basic functionality actually working:

  1. Business Calendar
  2. Business Calendar Pro
  3. Business Calendar 2
  4. Business Calendar 2 Pro
  5. aCalendar
  6. aCalendar+ Calendar & Tasks
  7. Today Calendar
  8. Today Calendar Pro
  9. Sol Calendar
  10. Jorte Calendar
  11. isoTimer
  12. vcCalendar Lite

Info you only need to read if interested:

In my testing:

  • Business Calendar 2, and Business Calendar 2 Pro appear to suffer from a serious bug that makes successful export/import impossible and poses serious privacy/security issues. See https://security.stackexchange.com/questions/124310/are-deleted-offline-calendar-events-in-android-actually-deleted

  • aCalendar and aCalendar+ Calendar & Tasks repeatedly failed to export calendar data without issues. These issues revealed what could possibly be reliability problems with how aCalendar and aCalendar+ manage the user's data.

  • Sol Calendar would not allow the user to edit or delete individual events in a repeated series. Also, although not a requirement, the UI employs mid-tone gray text in minuscule fonts on light-blue backgrounds, making the text impossible to read except in perfect lighting conditions.

  • Jorte Calendar does not depend on Android's calendar system, which made it look promising. But it would not allow the user to end a repeated event without undeleting all deleted events in the series. Although not requirements:

    • I found the UI to be poorly designed.
    • It does not allow .ics imports/exports (only .csv).
    • It requires recurring payments to the developer just to have more than one calendar.
  • isoTimer was buggy. It has it's own non-synced mode, which is nice. But editing the name of a recurring event would appear to change the name of the event (for all events in the series), but that change was not reflected when actually viewing the calendar. Also, just to backup your calendar locally, the user has to pay $1.97 every month.

  • vcCalendar Lite looked promising. It has a completely offline calendar mode that does not even use Android's calendar system. But when editing a recurring event to specify an end data, the user loses every edit they made to that series. For example, if the user had deleted the second event in the series, it will suddenly reappear.

  • Just to make sure, you don't need compatibility with any particular Google product, right? – Nicolas Raoul Jan 19 '16 at 6:06
  • @NicolasRaoul What is this Google of which you speak? – RockPaperLz- Mask it or Casket Jan 19 '16 at 6:14
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    @NicolasRaoul IOW, not at all ;-) – RockPaperLz- Mask it or Casket Jan 19 '16 at 6:15
  • Maybe not possible to do everything with a single app. You could try Offline Calendar and Calendar Import/Export for managing your calendars, plus whatever calendar app you like. – vclaw May 27 '16 at 12:05
  • @vclaw Thanks! I might have to reword the question a touch based on your feedback. What you propose is exactly what I've been trying to do, but I have not found any calendar app that can successfully perform items #1-#3 and not have so many bugs that it prevents successful export/import, even by the third party tools you mentioned. – RockPaperLz- Mask it or Casket May 27 '16 at 18:53

For quiet some time I'm using Personal Calendar. I wasn't sure if it supports all your requirements, so I made some quick tests:

  1. Offline calendar: Yes that was my reason to use it. With CalDAV-Sync I'm also able to synchronize it with my email provider (instead of Google cloud).
  2. Backup: Export to *.ics file.
  3. Edit events: Yes
  4. Edit events in in a repeated series: Tried it out and it worked, deleting the series with edited events was a bit tricky.
  5. Edit remaining events: Test worked.
  6. No bugs: Works like a charm. The only problem I encountered is, that the non-free version repeatedly checks the license (every week or so) and therefore needs WLAN at this moment.
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    Thanks so much. The developer has, perhaps accidentally, restricted his app to a very narrow locale. If the app has a feedback form, can you ask him to make it available everywhere? – RockPaperLz- Mask it or Casket May 28 '16 at 20:11
  • @RockPaperLizard - Didn't know that, too bad. You can contact him via his homepage: www.miwiapps.de the email adress you can find on the impressum page. Some time ago he even sent me the newest *.apk file to make some tests. If the language should be a problem, I will gladly help you out. – martinstoeckli May 29 '16 at 10:16
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    @RockPaperLizard - I had short email contact with the developer, and he was willing to publish it in other countries too. After the play store has synchronized the app information, you should be able to download and test it. – martinstoeckli Jun 1 '16 at 5:48
  • Thank you! That's kind of both of you! I just got it. I see the export requires a reasonable 1-time payment (which is fine), but before I pay, would you mind creating a new offline calendar, make 2 events in it, and then delete the first one. Then perform an export and see if the export contains 1 or 2 events. Of course, it should have only 1, but Business Calendar 2 Pro fails at this simple test. So before I buy yet another useless app, do you have a moment to give it a quick try? – RockPaperLz- Mask it or Casket Jun 1 '16 at 6:28
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    @RockPaperLizard - That's not a secret, but i doubt it helps you a lot, because it is a german site www.gmx.net. Actually every provider supporting the CalDav protocol can be used to synchronize a calendar. – martinstoeckli Jun 2 '16 at 7:52

I think Etar deserves a mention.

Edit: I noticed deleted events (even from years ago) in my .ics export, like you mentioned. I investigated, and initially thought that the problem didn't happen with Etar, so I mistakenly thought Samsung's S Planner was the culprit. However, I tried to reproduce the problem again, and found out that whether this problem occurs probably depends on the version of the com.android.providers.calendar (Calendar Storage) system app. I've updated the answer at security.stackexchange.com to reflect this as well.

With some other apps (like Samsung's S Planner) I noticed the same export issue that you mention (about deleted events still appearing in calendar exports). Etar doesn't suffer from the same issue, deleted events are properly cleaned up (even if you use local/offline calendars rather than cloud-based calendars).

The problem can observed by using the Calendar Import-Export app, and looking at the event counter. After deleting an event, it didn't decrease for me when using S Planner, but it does decrease when using Etar. So Etar does properly clean up.



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