There are two ways I’ve managed to do this:
1) The first one is by adding an .ICS cal to your calendars. This will result in a Read-Only calendar, which might be okay if you’re ok with adding all your appointments from your mobile phone. If this solution actually was stable, it could be enough in some instances. Unfortunately Kontact gives me regular warning messages that the calendar is not accessible. Therefore I wouldn’t recommend this approach at all.
Basically you need to login to your Google account and activate sharing of your calendar. Once you know the URL to use, this information can be entered in Kontact. After this sharing of the calendar can be disabled.
2) Two-way editing from your desktop and from your mobile is the way to go. I’ve successfully used this approach for two days now. This is how to do it:
Install the akonadi google resource package:
Start the akonadi tray icon from a shell:
Right-click the akonadi tray icon and choose Start Akonadi
It’s the blue sphere icon to the right in this picture:
You may need to expand the system tray if the icon is not visible.
Right-click the akonadi icon again and choose Configure…
You’ll be asked how you’d like Kwallet to handle future logins, click Always for convenience
Enter your google account name and password and click OK
Time to switch over to Kontact!
Click the green plus sign to add a new calendar of the type Akonadi:
Find the resource named akonadi_gcal_resource_1 and tick the Events box:
Click OK and you’re done!