Fragment - InstantiationException: no empty Constructor -> Google Maps v2?

Question

I get this error message, when I open a closed App again via App-Change button:

Caused by: java.lang.InstantiationEx         


        

Answer 1

But these FragmentContact is a public class in a *.java-file and has a public empty constructor.

The error is not complaining about FragmentContact. It is complaining about the first inner class of FragmentContact (FragmentContact$1). You cannot have a Fragment implemented as an inner class of anything, as it cannot be instantiated from outside the outer class. A static inner class is fine.