Split calendar notifications into channels

[Wv5twkFEKh54vo4tta9yu7dHa3]

Closes #1493, closes #67, closes #783, closes #1138

[Gitsaibot]

Thanks for the PR I think the users will love it ;). What does the @RequiresApi(Build.VERSION_CODES.O) refer to? So far we support Api 21.

[Wv5twkFEKh54vo4tta9yu7dHa3]

That code is only called by the createChannels function which has a if (Utils.isOreoOrLater()) guard around its content (because channels only exist for Oreo and later, so function calls regarding channels need Oreo or later)

[Gitsaibot]

Would it be possible to display the notification channel for each calendar directly in its settings and also change it there? Or a direct link to the channel setting?

[Wv5twkFEKh54vo4tta9yu7dHa3]

It's not possible to change it in the app, but I'll try to add a link to the channel setting

[Wv5twkFEKh54vo4tta9yu7dHa3]

How's this?

[Wv5twkFEKh54vo4tta9yu7dHa3]

Any other things you need to get this merged? :)

[Gitsaibot]

Any other things you need to get this merged? :)

No, for me it fits like this. Hopefully the users like it too ;)

[jondo]

(Note: F-Droid rollout is blocked by #1607.)

[Zocker1999NET]

Really, Thanks for implementing this feature, I'm sure this will also be helpful for me in the future.

(I do not know yet a better place to post this, so I post it here.)
However I want to add one thing: For me this was a breaking change because I configured the former notification channel to be able to override "Do not disturb" so I can use "Do not disturb" without blocking calendar notifications (Android has no setting for this for the whole app).
After this update, I missed important reminder notifications because the new notifications were not able to override Do not Disturb. It took me a week until I realized that this was the issue.
So please, the next time, announce this as a breaking change (with a pop-up in the app, or by making this feature optional, or at least by marking it in the release notes as a breaking change).

[Wv5twkFEKh54vo4tta9yu7dHa3]

@Zocker1999NET Sorry I really did not think of this usecase. I don't think there is much we should do about it now, two months later, but I hope the impact was not too great for you!