I thought it was awesome that Ubuntu 16.04 shipped with gnome-calendar, but I noticed that holidays were not included. I also noticed that there is an option to sync the calendar with an online one, how do I do this? I don't know of any online calendars I could use.
You can achieve that using the gnome control center in Ubuntu:
Type gnome-control-center into dash, settings will appear select that and select online account:
Then add your google account by clicking the plus sign at the bottom of the dialogue window that appears:
Then turn the calendar associated with that gmail account on, and this should sync it with Ubuntu Calendar.:
If you want more Calendars set it up in Calendar in google from the settings options top right corner of calendar page.
Google has changed how apps communicate with your google account so you have to setup your phone from here else you won't be able to add an account.
Go to google calendar:
Get to settings, top right of page:
In ther click on the Calendars tab, top left of page:
In there click on export calendars:
That will export your calendar in a .ics file format. Now Lets instruct Calendar to sync back in Ubuntu desktop.
.ics fileExtract the downloaded .ics file
Start up Calendar and click on Calendar Settings
Form the dialogue box that appears select from file
Navigate to that extracted .ics file location, select it and choose the one without the #[tag] at the start of the name.
Back in Calendar select synchronize and make sure your internet is working and after a few minutes your synced calendars will appear.
To get all my Google calendars to sync, I had to go enable syncing them in a hidden Google sync settings page:
https://calendar.google.com/calendar/syncselect
Then I had to disable Calendar for my Google account in Gnome Online Accounts settings, and re-enable it. After that all my calendars are synced.
The same is actually needed for the Windows 10 Calendar, which is how I found it.
For Ubuntu 20.04, following these steps should enable syncing Google services.
Go to Settings from the Dash.
From Online Accounts(1) select Google(2).
Give your Username for Google account.
Give your Password for Google account.
Allow access on your Google account.
Select what services you want to be synced.
I think ubuntu 17.10 and 18.04 do not sync the Gnome Calendar with google calendar automatically.
I would suggest, since Evolution Mail treats the Gnome Contacts and Calendar, that you install Evolution with the important file evolution-data-server. Then you have to configure the google account within the Evolution Calendar. Some pictures of this operation were shown upstairs.
In the settings it is possible to choose even the important option "sync time" (the default 30 min is for me too much so I set it to 1 min) which is the time lapse between every synchronization. Finally you can see all Google events in the Gnome Calendar in the top bar. After these operations you can remove Evolution Mail but not evolution-data-server which is necessary to do the sync.
Note: you have to do this operation if you want to use Thunderbird and not Evolution Mail. Thunderbird is the default application in Ubuntu 18.04.
For me, there was a bug with the gnome-calendar app where I could not click the "Add" button (the one in your screenshot), no matter what I entered.
I found a workaround by using the way the GOA (Gnome Online Accounts) works:
In short, since Evolution also uses the GOA, just like gnome-calendar does, any calendar that you add there will also be added to gnome-calendar. The same should in theory apply for every other app that uses the GOA.
Regarding which calendar you should use, it depends. Holidays can be very different in different locations or even schools, so you need to find a source for yourself.
In general you have two options of adding holidays to gnome-calendar: Import an offline file (.ics) or the one I described above. Using one of the providers from the GOA Menu, like Google, Nextcloud or Microsoft Exchange is just a bit easier than importing a calendar from a custom provider.
More on this matter: ctrl.blog
This issue was fixed for me on Ubuntu 18.04 after I did the following (in terminal):
pkill -f calendar.rm -rf ~/{.local/share,.cache}/evolution/calendar/Now start Gnome Calendar again as usual.
After this it downloaded all the updated calendar entries from my Google calendar. Also, the Synchronize button started working and the new entries from Google calendar started being visible in Gnome Calendar.
Start by adding your google account to your online accounts in the settings. Make sure to be connected to the internet so that your online account calendar will automatically sync with the local calendar.
In your case as you don't see the holidays,
Go to https://calendar.google.com and login to access your calendar. On the left pane, you will see my calendars, if holidays is not ticked, tick that checkbox.
If this option is not there, click the plus option on other calendars, and select browse calendars of interest, select the holidays that apply to you. After that save and reload the page.this will sync with your local calendar
Hope this helps,am using Ubuntu 18.04
November 2022: this link shows how to get a secret address to share your calendar with Desktop applications. I confirm that it work to sync and to see (not to write) appointments on google-calendar. Again, do not expect to be able to create an appointment google-calendar and have it synced on the cloud.
https://support.google.com/calendar/answer/37648#private&zippy=%2Csecret-address
If you're looking to add a simple published ical link/URL. I just installed Evolution (which interfaces with gnome-calendar apparently) and add it that way.
sudo apt install evolution