android - How to pass a string from a list in one activity to another -

what convert list of user string , on click pass selected string next activity. tried on messaging feature have used on app , has worked fine. attempting work gallery feature. section supposed find users in parse, convert them string , display them on list view. on click supposed collect string on list , use in gallery view activity display images username equal 1 selected list.

listuseractivity

list view of usernames saved in database.

//display clickable list of users private void setconversationslist() {     currentuserid = parseuser.getcurrentuser().getobjectid();     names = new arraylist<string>();      parsequery<parseuser> query = parseuser.getquery();     query.wherenotequalto("objectid", currentuserid);     query.findinbackground(new findcallback<parseuser>() {         public void done(list<parseuser> userlist, com.parse.parseexception e) {             if (e == null) {                 (int i=0; i<userlist.size(); i++) {                     names.add(userlist.get(i).getusername().tostring());                 }                  userslistview = (listview)findviewbyid(r.id.userslistview);                 namesarrayadapter =                         new arrayadapter<string>(getapplicationcontext(),                                 r.layout.user_list_item, names);                 userslistview.setadapter(namesarrayadapter);                  userslistview.setonitemclicklistener(new adapterview.onitemclicklistener() {                     @override                     public void onitemclick(adapterview<?> a, view v, int i, long l) {                         openconversation(names, i);                     }                 });              } else {                 toast.maketext(getapplicationcontext(),                         "error loading user list",                         toast.length_long).show();             }         }     }); } 

what happens on clicking name on list view.

public void openconversation(arraylist<string> names, int pos) {     parsequery<parseuser> query = parseuser.getquery();      query.whereequalto("username", names.get(pos));     query.findinbackground(new findcallback<parseuser>() {         public void done(list<parseuser> user, com.parse.parseexception e) {             if (e == null) {                 // intent intent = new intent(getapplicationcontext(), gridactivity.class);                 intent intent = new intent(listusersactivity.this, gridactivity.class);                 intent.putextra("recipient_id", user.get(0).getobjectid());                 startactivity(intent);             } else {                 toast.maketext(getapplicationcontext(),                         "error finding user",                         toast.length_short).show();             }         }     }); } 

galleryactivity

i've tried convert recipient_id string variable called recipientid , add in line query.whereequalto("username", recipientid); keeps creating message telling me null.

 @override     protected void doinbackground(void... params) {         // create array          intent intent = getintent();         recipientid = intent.getstringextra("recipient_id");         currentuserid = parseuser.getcurrentuser().getobjectid();           phonearraylist = new arraylist<phonelist>();         try {              parsequery<parseobject> query = new parsequery<parseobject>("imageupload");               usernametxt = usernameimgshow.gettext().tostring();             //query.whereequalto("username", userstr);             query.whereequalto("username", recipientid);             query.orderbyascending("createdat");             ob = query.find();             (parseobject country : ob) {                 parsefile image = (parsefile) country.get("imagefile");                 phonelist map = new phonelist();                 map.setphone(image.geturl());                 phonearraylist.add(map);             }         } catch (parseexception e) {             log.e("error", e.getmessage());             e.printstacktrace();         }         return null;     } 

if second activity's launch mode singleinstance or singletop , it's created when send intent desired intent arrive in onnewintent. if case, current getintent returns intent when activity first created.