I have came up with this post but it is for the deprecated Google Maps API
http://tech.truliablog.com/2012/02/23/custom-map-markers-for-android-google-maps/
I know this question is old but I'll post my answer here in case it helps someone.
None of the above solutions were working for me because
I already have custom icons for markers in my app
My app display potentially thousands of different marker titles so creating that many images in memory would be a performance problem
As the marker icons become bigger, the map becomes very quickly unreadable
I found no solution on the internet so I rolled up my sleeves and made this library which solves my problem, hopefully it will help others too:
https://github.com/androidseb/android-google-maps-floating-marker-titles
Here is a preview of how it works: