fruux Android app / Sync Plugin
We absolutely agree that the Android support is currently lacking.
Right now our suggestion is to use the third party extensions for CardDAV and CalDAV from http://dmfs.org
Instead of building another third party solution we hope that Google will finally implement native support for CardDAV and CalDAV – since Android is an open system it should absolutely support open standards.
We have some hope that this might happen soon since CardDAV and CalDAV support are one of the biggest feature requests for Android:
So lets hope that Google finally wakes up instead of keeping Android locked down to it’s own services.
Don't count on Google!
My suggestion is to have a look at https://f-droid.org/repository/browse/?fdid=org.gege.caldavsyncadapter :-)
It's a calDAV sync adapter just like Marten Gajda's app CalDAV-Sync (dmfs.org). Not as mature yet but it's free and open source, so feel free to improve it!
Also available at Google Play: https://play.google.com/store/apps/details?id=org.gege.caldavsyncadapter
Though you could kill 2 birds with one stone, or should I say... Zwei Fliegen mit einer Klappe schlagen, if one could just sync Fruux account online with Google Contacts. :)