I dont get the point, why I have to code so much for it. Like, I dont want to care about...
- the position of the balloon (I just want to assign a geopoint)
- the layout of a basic balloon (Later on I might want to implement a xml based layout)
- the number of shown balloons (only display one at a time)
- the open/close behaviour of the balloon (close, when an other bollon is tabbed)
Update
Solved it! See my answer below...
Here is the "the missing widget"...
Balloons without icons: https://github.com/jgilfelt/android-mapviewballoons#readme
Balloons with icons (extends Jeff Gilfelt's project):
https://github.com/galex/android-mapviewballoons(Offline, see comments to this answer)