Ok guys it was my error, because the Tobii team sent me the libraries for Android.
Now I have my example android app (compiled with the libraries) and my driver for 64 bit Android Platform installed. I connect the Tobii rex with my Android Smartphone through an USB adaptor, but when I look for the Tobii within the app (the app the Tobii team sent me with the libraries), nothing happens.
What am I missing? Do I need root permissions?