Fragment fragment = new MyAccount();
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment).addToBackStack(null)
.commit();

if(RegDetails.contains("MSISDN")&&RegDetails.contains("PIN")){
            Fragment fragment = new ReferFriend();
            FragmentManager fragmentManager = getFragmentManager();
            fragmentManager.beginTransaction()
            .replace(R.id.frame_container, fragment)
            .commit();
        }