checkbox - Adding checked items in a custom list view to array list in android -

hi writing program using custom listview checkbox. intention start new activity when clicking button (add) , new activity displays selected values listview.i getting error when try add values

the error occuring line is

selecteditems.add(adapter.getitem(position));

if comment line can check box shows eror when click "add" button.

here complete code.

my mainactivity

homepage.java

public class homepage extends activity { private listview listview1; listadapter adapter; button btn; sparsebooleanarray checkedvalue; arraylist<list> selecteditems; string name; @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_home_page);      list device_data[] = new list[]                 {         new list(r.drawable.ic_pic , "actvity1"),         new list(r.drawable.ic_pic, "actvity2"),         new list(r.drawable.ic_pic, "actvity3"),         new list(r.drawable.ic_pic, "actvity4"),         new list(r.drawable.ic_pic, "actvity5")                       };       listadapter adapter = new listadapter(this,  r.layout.list_viewrow, device_data);          listview1 = (listview)findviewbyid(r.id.listview1);         view header = (view)getlayoutinflater().inflate(r.layout.listview_header, null);        listview1.addheaderview(header);         listview1.setadapter(adapter);          log.i("check box status", ""+listadapter.listholder.class);               btn= (button)findviewbyid(r.id.add);              btn.setonclicklistener(new view.onclicklistener() {                     @override                     public void onclick(view v) {                           string[] outputstrarr = new string[selecteditems.size()];                         checkedvalue= listview1.getcheckeditempositions();                         (int = 0; < selecteditems.size(); i++) {                             outputstrarr[i] = selecteditems.get(i).tostring();                         }                         intent intent = new intent(getapplicationcontext(),                                checkedvalues.class);                          bundle b = new bundle();                          b.putstringarray("selecteditems", outputstrarr);                           // add bundle intent.                          intent.putextras(b);                         startactivity(intent);                     }                 });         } private class listadapter extends arrayadapter<list> {     context context;      int layoutresourceid;        boolean checkvalue;     list data[] = null;      public listadapter(context context, int layoutresourceid, list[] data) {         super(context, layoutresourceid, data);         this.layoutresourceid = layoutresourceid;         this.context = context;         this.data = data;     }      @override     public view getview(final int position, view convertview, viewgroup parent) {         view row = convertview;         final listholder holder;          if(row == null)         {             layoutinflater inflater = ((activity)context).getlayoutinflater();             row = inflater.inflate(layoutresourceid, parent, false);              holder = new listholder();             holder.imgicon = (imageview)row.findviewbyid(r.id.imgicon);             holder.txttitle = (textview)row.findviewbyid(r.id.txttitle);             holder.checkbox=(checkbox) row.findviewbyid(r.id.check);              holder.checkbox.setoncheckedchangelistener(new compoundbutton.oncheckedchangelistener() {                  @override                 public void oncheckedchanged(compoundbutton buttonview,                     boolean ischecked) {                            selecteditems.add(adapter.getitem(position));                    }                 });              row.settag(holder);         }         else         {             holder = (listholder)row.gettag();         }          list list = data[position];         holder.txttitle.settext(list.title);         holder.imgicon.setimageresource(list.icon);          return row;     }       class listholder     {         imageview imgicon;         textview txttitle;         checkbox checkbox;     }  } } 

and second activity

checkedvalues.java

public class checkedvalues extends activity {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_checked_values);      bundle b = getintent().getextras();     string[] resultarr = b.getstringarray("selecteditems");     listview lv = (listview) findviewbyid(r.id.outputlist);      arrayadapter<string> adapter = new arrayadapter<string>(this,             android.r.layout.simple_list_item_1, resultarr);     lv.setadapter(adapter);  } 

}

thanks in advance..

initialize "arraylist"

arraylist<list> selecteditems; protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_home_page); selecteditems = new arraylist<list>(); }