Change layout using a spinner in Android -

i'm trying change layout of activity according selection inside spinner. after first selection, spinner become white , i'm not able decide selection. code i'm using following:

public class mainactivity extends activity implements onitemselectedlistener {  spinner spinner; string[] options = { "modulo1", "modulo2" };  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      spinner = (spinner) findviewbyid(r.id.spinner);     arrayadapter<string> adapter_state = new arrayadapter<string>(this,             android.r.layout.simple_spinner_item, options);     adapter_state             .setdropdownviewresource(android.r.layout.simple_spinner_dropdown_item);     spinner.setadapter(adapter_state);     spinner.setonitemselectedlistener(this);  }  int check = 0;  public void onitemselected(adapterview<?> parent, view view, int position,         long id) {     check = check + 1;     if (check > 1) {         int selstate = spinner.getselecteditemposition();         switch (selstate) {         case 0:             setcontentview(r.layout.activity_main);              break;         case 1:             setcontentview(r.layout.activity2_main);              break;          }      } }  @override public void onnothingselected(adapterview<?> arg0) {     // todo auto-generated method stub  }  // @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; } 

}

any suggestion? thanks

the spinner referring in first activity. after have replaced content, spinner isn't there anymore. if have spinner in second layout, have reconnect , set listener again. have run oncreate stuff after every setcontentview...

as side note, whatever trying do, not way go. show full layout, better use activity.