Android - How to manage multiples user levels and types

I have project be used by different group then user.

For example: one group is secretary user, another is the admin user, medical user.

Currently my code this so below:

 if(App.getInstance().getCustomer().isAdmin())
        replaceFragment(R.id.view_main,new AdminFragment);
 if(App.getInstance().getCustomer().isMedical())
        replaceFragment(R.id.view_main,new MedicalFragment);

My question is, what is the way more sophisticated to accomplish this control