android - Filtering listView data using SimpleAdapter -

i need filtering work. listview displayed correctly, when enter letter in search field gives error

java.lang.nullpointerexception 

and application closes.

here code snippet activity think have fix, don't know how:

    protected void onpostexecute(string file_url) {         // dismiss dialog after getting albums         pdialog.dismiss();         // updating ui background thread         runonuithread(new runnable() {             public void run() {                 /**                  * updating parsed json data listview                  * */                  listadapter adapter = new simpleadapter(                         winesearchactivity_2.this, albumslist,                         r.layout.activity_search_list_of_wines, new string[] {                                 tag_wine_id, tag_wine_name,                                 tag_wine_country_id,                                 tag_wine_country_flag_pic }, new int[] {                                 r.id.wine_id, r.id.wine_name,                                 r.id.wine_country_id, r.id.imageview2 });                 listview lv = getlistview();                 layoutinflater inflater = getlayoutinflater();                 view header = inflater.inflate(r.layout.header,                         (viewgroup) findviewbyid(r.id.linearlayoutheader));                 view search_box = inflater.inflate(r.layout.search_box,                         (viewgroup) findviewbyid(r.id.relativelayoutsearchbox));                 lv.addheaderview(header, null, false);                 lv.addheaderview(search_box, null, false);                  // updating listview                 setlistadapter(adapter);                  inputsearch = (edittext) findviewbyid(r.id.inputsearch);                  inputsearch.addtextchangedlistener(new textwatcher() {                      @override                     public void ontextchanged(charsequence cs, int arg1, int arg2, int arg3) {                         // when user changed text                         ((simpleadapter)winesearchactivity_2.this.adapter).getfilter().filter(cs);                       }                      @override                     public void beforetextchanged(charsequence arg0, int arg1, int arg2,                             int arg3) {                         // todo auto-generated method stub                       }                      @override                     public void aftertextchanged(editable arg0) {                         // todo auto-generated method stub                      }                 }); 

set listadapter adapter globally. sure , work. kamal