parse.com - How to add data from parse to an Android ListView -

i have parse account. got data parse cannot add arraylist nor listview.

i managed data string not able add list view.

here code:

public class student_login extends activity implements view.onclicklistener {  private textview mtextview; arraylist arraylist;;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_student_login);      arraylist = new arraylist();     setlisdata();      arrayadapter adapter = new arrayadapter<string>(this, r.layout.activity_list_view, arraylist);      listview listview = (listview) findviewbyid(r.id.listview);     listview.setadapter(adapter);      button sub=(button)findviewbyid(r.id.button2);     sub.setonclicklistener(this);  }  private void setlisdata() {      parseuser currentuser = parseuser.getcurrentuser();     string curser = currentuser.getusername().tostring();     final string sc = currentuser.getstring("school");     toast.maketext(getapplicationcontext(), "your id " + sc, toast.length_short).show();      parsequery<parseobject> query = parsequery.getquery("staff");     query.whereequalto("school", sc);     query.findinbackground(new findcallback<parseobject>() {         @override         public void done(list<parseobject> objects, parseexception e) {             (parseobject parseobject : objects) {                 string name = parseobject.getstring("name");                 arraylist.add(name);                 toast.maketext(getapplicationcontext(), name, toast.length_long).show();              }         }     }); }  public void onclick(view v) {      switch (v.getid()){         case r.id.button2:              // r =movie.getratingstar();             parseuser.logout();             parseuser currentuser = parseuser.getcurrentuser(); // should null isn't...             invalidateoptionsmenu();             toast.maketext(getapplicationcontext(), "disconnected...", toast.length_long).show();              intent intent = new intent(this,login.class);             startactivityforresult(intent,0);             finish();              break;     } }  } 

at runtime output names displayed in toast not adding list view.thank you.

do below changes in code works fine

arrayadapter adapter  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_student_login);      arraylist = new arraylist();       adapter = new arrayadapter<string>(this, r.layout.activity_list_view, arraylist);      listview listview = (listview) findviewbyid(r.id.listview);     listview.setadapter(adapter);      button sub=(button)findviewbyid(r.id.button2);     sub.setonclicklistener(this);      setlisdata(); }  private void setlisdata() {      parseuser currentuser = parseuser.getcurrentuser();     string curser = currentuser.getusername().tostring();     final string sc = currentuser.getstring("school");     toast.maketext(getapplicationcontext(), "your id " + sc, toast.length_short).show();     if(arraylist.size()>0){      arraylist.clear();     }     parsequery<parseobject> query = parsequery.getquery("staff");     query.whereequalto("school", sc);     query.findinbackground(new findcallback<parseobject>() {         @override         public void done(list<parseobject> objects, parseexception e) {             (parseobject parseobject : objects) {                 string name = parseobject.getstring("name");                 arraylist.add(name);                 toast.maketext(getapplicationcontext(), name, toast.length_long).show();              }              if(arraylist.size()>0 && adapter != null){                adapter.notifydatasetchanged();             }         }     });   }