android - Why is my doInBackground called so many times? -

i have navigation drawer , onclick follows:

private class slidemenuclicklistener implements     listview.onitemclicklistener {         @override         public void onitemclick(adapterview<?> parent, view view, final int position,                 long id) {             //  system.out.println("clicked");             mdrawerlayout.postdelayed(new runnable() {                 @override                 public void run() {                     displayview(position);                 }             }, 200);          }     } 

my displayview(position); method is:

private void displayview(int position) {         // update main content replacing fragments         fragment fragment = null;         switch (position) {         case 0:              fragment = new fragmenttab1();             break;         case 1:             fragment = new fragmenttab2();             break;         case 2:             fragment = new fragmenttab3();             break;         case 3:             fragment = new fragmenttab3();             //create dialog                 break;         default:             break;         }          if (fragment != null) {             fragmentmanager fragmentmanager = getfragmentmanager();             fragmentmanager.begintransaction()             .replace(r.id.frame_container, fragment).commit();              // update selected item , title, close drawer             mdrawerlist.setitemchecked(position, true);             mdrawerlist.setselection(position);             settitle(navmenutitles[position]);             mdrawerlayout.closedrawer(gravity.left);         } else {             // error in creating fragment             log.e("mainactivity", "error in creating fragment");         }     } 

now in oncreateview of fragment class call:

new listloader().execute(getactivity());

here implementation:

public class listloader extends asynctask<context, void, curadapter> {          progressdialog asycdialog = new progressdialog(getactivity());         @override         protected void onpreexecute() {             // todo auto-generated method stub              asycdialog.setmessage("working");             asycdialog.getwindow().setgravity(gravity.center_vertical);             asycdialog.getwindow().setgravity(gravity.center_horizontal);             asycdialog.setcancelable(false);             asycdialog.show();             super.onpreexecute();         }          protected void onpostexecute(curadapter result) {             asycdialog.cancel();             lv.setadapter(result);         //  dbhelper.close();         }          @override         protected curadapter doinbackground(context... params) {              system.out.println("loading list");             dbhelper.open();             final string status = fetch();             cursor mcur;              mcur = dbhelper.magicquery(status);              cur = new curadapter(getactivity(), mcur,0);                   cur.setfilterqueryprovider(new filterqueryprovider() {                 public cursor runquery(charsequence constraint) {                     return dbhelper.getdirectorylist(constraint,status);                 }             });                return cur;         }       } 

the message loading list appears each time open , close navigation drawer, making execute? have put system.out message in oncreateview not show up, while calling asynctask oncreateview. miss here?

i face flicker onclick of navdrawer item fragment transition, though using asynchronous method. have to, against wish use loading progress dialog.

edit:

got culprit:

searchview.onquerytextlistener textchangelistener = new searchview.onquerytextlistener() {         @override         public boolean onquerytextchange(string newtext){              if (textutils.isempty(newtext)){                 new listloader().execute(getactivity());             }             else {                 cursoradapter filteradapter = (cursoradapter) cur;                 filteradapter.getfilter().filter(newtext.tostring());             }              return true;         }          @override         public boolean onquerytextsubmit(string query) {             return true;         }     }; 

edit fiddled around onquerytextlistener , resolved.

    int ix =1;      searchview.onquerytextlistener textchangelistener = new searchview.onquerytextlistener() {         @override         public boolean onquerytextchange(string newtext){             if (textutils.isempty(newtext)){                 if(ix == 2)                     new listloader().execute(getactivity());               }             else {                 ix = 2;                 cursoradapter filteradapter = (cursoradapter) cur;                 filteradapter.getfilter().filter(newtext.tostring());             }              return true;         }          @override         public boolean onquerytextsubmit(string query) {             return true;          }     }; 

the reason:

this observed behavior when using fragments navigationdrawer. each time navigationdrawer opened, current fragment's onpause() , ondestroy() called, , each time drawer closed, current fragment's oncreateview() , onresume() called.

in nutshell, fragment destroyed , created anew every open/close cycle of drawer. that's why asynctask called repeatedly.

the solution(s):

you have 2 options:

1. save state of each fragment in onsavedinstancestate() , restore saved data in oncreate(). execute asynctask if savedinstancestate null in oncreate() or oncreateview().

2. try using activitys instead of fragments. activitys not created anew when drawer opened/closed.