Android Application Crashing When Switching Activities -

upon clicking item of listview want new activity start up. when run through emulator application crashes every time. positive androidmanifest correct well. appreciated.

public static class sectionfragment extends listfragment {     /**      * fragment argument representing section number      * fragment.      */     public static final string arg_section_number = "section_number";     private string dataarrayone[];     private string dataarraytwo[];      public sectionfragment() {         dataarrayone = new string[] {                 "steven's portfolio",                 "sean's portfolio",                 "logan's portfolio",         };          dataarraytwo = new string[] {                 "goog",                 "yhoo",                 "aapl",                 "msft"         };     }      @override     public void oncreate(bundle savedinstancestate)     {         super.oncreate(savedinstancestate);         switch(getarguments().getint(arg_section_number))         {         case 0:             listadapter listadapter = new arrayadapter<string>(getactivity(), android.r.layout.simple_list_item_1, dataarrayone);             setlistadapter(listadapter);             break;         case 1:             listadapter listadapter1 = new arrayadapter<string>(getactivity(), android.r.layout.simple_list_item_1, dataarraytwo);             setlistadapter(listadapter1);         }     }      @override     public view oncreateview(layoutinflater inflater, viewgroup container,             bundle savedinstancestate) {         return inflater.inflate(r.layout.fragment_main_dummy, container, false);     }      @override     public void onlistitemclick(listview list, view v, int position, long id)     {         toast.maketext(getactivity(), getlistview().getitematposition(position).tostring(), toast.length_short).show();          intent intent = new intent(getactivity(), portfolio_select.class);         intent.putextra("username", getlistview().getitematposition(position).tostring());         startactivity(intent);      } 

androidmanifest.xml

<activity         android:name=".portfolio_select"         android:label="@string/app_name" >         <intent-filter>             <action android:name="android.intent.action.main" />              <category android:name="android.intent.category.default" />         </intent-filter> </activity> 

portfolio_select code

public class portfolio_select extends activity {      // variables go here      textview display;      /** called when activity first created. */     @override     public void oncreate(final bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(com.example.stockticker.r.layout.activity_main);            display.settext("stocks go here!");       }   } 

textview display; 

is declared, references null since findviewbyid() hasn't been used give else hold.

this means when

display.settext("stocks go here!"); 

is called, you'll npe.

so use make sure have textview in r.layout.activity_main id, use findviewbyid() give display textview reference

setcontentview(com.example.stockticker.r.layout.activity_main);  display = (textview) findviewbyid (r.id.your_text_view_id);  display.settext("stocks go here!"); 

if there other issues, add stack trace question, there's no other guessing involved.