android - AsyncTask not updating the TextView inside First fragment in Viewpager -

i've started programming android (from ios), , working boiler plate code adt generates me when choose activity+scrollable tabs option in new project wizard. in code below i've marked same in comments.

the scenario enter text in edittext, press button , fetch data webservice. wish put data in appropriate fragment (there 3 fragments) inside view pager. getting data , able set on fragment 2 , fragment 3 when swipe, data relevant fragment 1 not getting set once asyctask complete. however, after swiping fragment 3, when come fragment 1, data there.

here code:

activity

public class xxxx extends fragmentactivity {  sectionspageradapter msectionspageradapter; viewpager mviewpager;  //my additions boiler plate source generated adt public arraylist<string> p1t,p2t,p3t,p4t; private edittext edittext; private button button; private boolean flag;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.konjugation);     msectionspageradapter = new sectionspageradapter (getsupportfragmentmanager());     mviewpager = (viewpager) findviewbyid(r.id.pager);     mviewpager.setadapter(msectionspageradapter);      //my additions boiler plate source below     flag=false;     p1t = new arraylist<string>(6);      p2t = new arraylist<string>(6);      p3t = new arraylist<string>(6);      p4t = new arraylist<string>(6);       edittext = (edittext) findviewbyid(r.id.edittext1);     button = (button) findviewbyid(r.id.button1);      button.setonclicklistener(new onclicklistener() {         @override         public void onclick(view v) {             string url = edittext.gettext().tostring();             if(!url.isempty()) {                 url="http://.../?q="+edittext.gettext().tostring();                 pasynctask task = new pasynctask();                 task.execute(url);             }      mviewpager.setonpagechangelistener(new viewpager.simpleonpagechangelistener(){         @override         public void onpageselected(int pos) {             if(flag==true) {                 if(pos==0) dummysectionfragment.settext(p4t,p1t);                 if(pos==1) dummysectionfragment.settext(p4t,p2t);                 if(pos==2) dummysectionfragment.settext(p4t,p3t);             }             else {                 log.d("ts","data not arrived");             }         }     }); }  @override public boolean oncreateoptionsmenu(menu menu) {     getmenuinflater().inflate(r.menu.konjugation, menu);     return true; } 

pageradapter

    public class sectionspageradapter extends fragmentstatepageradapter {     public sectionspageradapter(fragmentmanager fm) {         super(fm);     }      @override     public fragment getitem(int position) {         fragment fragment = new dummysectionfragment();         return fragment;     }      @override     public int getcount() {         return 3;     }      @override     public charsequence getpagetitle(int position) {         switch (position) {         case 0:             return getstring(r.string.title_section1);         case 1:             return getstring(r.string.title_section2);         case 2:             return getstring(r.string.title_section3);         }         return null;     }      @override     public void notifydatasetchanged() {         int pos = mviewpager.getcurrentitem();         if(pos==0) dummysectionfragment.settext(p4t,p1t);         else if(pos==1) dummysectionfragment.settext(p4t,p2t);         else if(pos==2) dummysectionfragment.settext(p4t,p3t);     }  } 

asynctask

private class pasynctask extends asynctask<string, void, string> {     @override     protected string doinbackground(string... params)      {         string response = "";         (string url : params) {             defaulthttpclient client = new defaulthttpclient();             httpget httpget = new httpget(url);             try {                 httpresponse execute = client.execute(httpget);                 inputstream content = execute.getentity().getcontent();                 bufferedreader buffer = new bufferedreader(new inputstreamreader(content));                 string s = "";                 while ((s = buffer.readline()) != null) {                     response += s;                 }             } catch (exception e) {                 e.printstacktrace();             }         }         return response;     }      protected void onpostexecute(string result)      {         try {             p1t.clear();             p2t.clear();             p3t.clear();              //do important result here               flag=true;             //hoping somehow viewpager adapter refresh view             msectionspageradapter.notifydatasetchanged();         } catch (exception e) {             e.printstacktrace();         }     } } 

viewpager's fragment

public static class dummysectionfragment extends fragment {     private static textview dummytextview;      @override     public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) {         view rootview = inflater.inflate(r.layout.fragment_konjugation_dummy, container, false);         dummytextview = (textview) rootview.findviewbyid(r.id.section_label);         return rootview;     }      public static void settext(arraylist<string> s, arraylist<string> t) {         try {             dummysectionfragment.dummytextview.settext("");             for(int i=0;i<s.size();i++) {                 dummysectionfragment.dummytextview.append(s.get(i)+" "+t.get(i)+"\n\n");             }         } catch(nullpointerexception e) {             e.printstacktrace();         }     } } } 

i feel kinda lost, after reading threads here. please :-(

you should update inside of runonuithread() method, takes runnable object argument, can pass implementation in it.