android - Type mismatch: cannot convert from FragmentOne to Fragment when create FragmentOne in seperate class? -

when fragment fr=new fragmentone(); gives me error if create fragmentone() class in same activity not give error when create fragmentone() out side of activity gives me error

public class mainactivity extends actionbaractivity implements         navigationdrawerfragment.navigationdrawercallbacks {      /**      * fragment managing behaviors, interactions , presentation of      * navigation drawer.      */     private navigationdrawerfragment mnavigationdrawerfragment;      /**      * used store last screen title. use in      * {@link #restoreactionbar()}.      */     private charsequence mtitle;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          mnavigationdrawerfragment = (navigationdrawerfragment) getsupportfragmentmanager()                 .findfragmentbyid(r.id.navigation_drawer);         mtitle = gettitle();          // set drawer.         mnavigationdrawerfragment.setup(r.id.navigation_drawer,                 (drawerlayout) findviewbyid(r.id.drawer_layout));          fragment fr=new fragmentone();         fragmentmanager fragmentmanager = getsupportfragmentmanager();         fragmentmanager .begintransaction().replace(r.id.container, fr).commit();      }      @override     public void onnavigationdraweritemselected(int position) {         // update main content replacing fragments        } 

guess problem package imports should have figured out. either use android.app.fragment (or) android.support.v4.app.fragment based on app requirements :-)