android - Issue with ViewHolder pattern -

so i'm using known viewholder pattern in app. viewholder:

protected static class viewholder{     final imageview itemimage;     final textview txtname;     final textview txttitle;     final webview webview;      public viewholder (final imageview itemimage,  final textview txtname, final textview txttitle, final webview webview){         this.itemimage = itemimage;         this.txtname = txtname;         this.txttitle = txttitle;         this.webview = webview;     }      public viewholder (view convertview){         itemimage = (imageview) convertview.findviewbyid(r.id.fav_item_icon);         txtname = (textview) convertview.findviewbyid(r.id.fav_item_name);         txttitle = (textview) convertview.findviewbyid(r.id.fav_item_title);         webview = (webview) convertview.findviewbyid(r.id.fav_webview);     } } 

so works fine if use 1st constructor like:

...                 public view getview(final int position, view convertview, final viewgroup parent) {                      final searchable searchresultsitem = searchresults.get(position);                      viewholder viewholder = null;                     if (convertview==null){                         convertview = inflater.inflate(r.layout.search_list_item, null);                          final imageview itemimage = (imageview) convertview.findviewbyid(r.id.search_item_icon);                         final textview txtname = (textview) convertview.findviewbyid(r.id.search_item_name);                         final textview txttitle = (textview) convertview.findviewbyid(r.id.search_item_title);                         final webview webview = (webview) convertview.findviewbyid(r.id.search_webview);                         viewholder = new viewholder(itemimage, txtname, txttitle, webview);                          convertview.settag(viewholder);                     }else                         viewholder = (viewholder)convertview.gettag();                      viewholder.webview.setfocusable(false);     ... 

but fails if try use 2nd constructor:

...                 public view getview(final int position, view convertview, final viewgroup parent) {                      final searchable searchresultsitem = searchresults.get(position);                      viewholder viewholder = null;                     if (convertview==null){                         convertview = inflater.inflate(r.layout.search_list_item, null);                          viewholder = new viewholder(convertview);                         convertview.settag(viewholder);                     }else                         viewholder = (viewholder)convertview.gettag();                      viewholder.webview.setfocusable(false);     ... 

it crashes npe @ line viewholder.webview.setfocusable(false). when try debug says created viewholder instance has fields null. why happen?

the ids seems different, intentional?
final webview webview = (webview)convertview.findviewbyid(r.id.search_webview); r.id.search_webview (this 1 works)

and

webview = (webview) convertview.findviewbyid(r.id.fav_webview);
r.id.fav_webview (this 1 not work)