json - Couldn't fix Future Task exception in android -

i'm pretty new in android programming, , i'm trying write piece of codes include httppost,json,asynctask etc. i'm getting error couldn't fix it.

public void onclick(view v) {              mainactivity.this.runonuithread(new runnable() {                  public void run() {                     requestloginfromserver rl = new requestloginfromserver();                     rl.execute().tostring();                  }             });         }     });  }  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; }  public class requestloginfromserver extends         asynctask<object, object, object> {     textview txt = (textview) findviewbyid(r.id.textview1);     edittext edt = (edittext) findviewbyid(r.id.edittext1);      @override     protected object doinbackground(object... params) {          httpclient httpclient = new defaulthttpclient();         httppost httppost = new httppost(                 "http://shopstable.turkcell.com.tr/timmenu/getperosconfig.do");         httppost.setheader("content-type", "application/json");          try {              httpresponse response = httpclient.execute(httppost);             httpentity resentity = response.getentity();             = resentity.getcontent();         } catch (unsupportedencodingexception e) {             e.printstacktrace();         } catch (clientprotocolexception e) {             e.printstacktrace();         } catch (ioexception e) {             e.printstacktrace();             // strjson = null;         }         try {             bufferedreader reader = new bufferedreader(                     new inputstreamreader(is, "utf-8"), 8); // iso-8859-1 //             stringbuilder sb = new stringbuilder();             string line = null;             while ((line = reader.readline()) != null) {                 sb.append(line + "/n");             }             is.close();             strjson = sb.tostring();         } catch (exception e) {          }          try {             if (strjson != null) {                 jobj = new jsonobject(strjson);                 string text = jobj.get("masterperosactive").tostring();                 edt.settext(text);              } else {                 jobj = null;             }         } catch (jsonexception e) {         }         return "executed";     } 

and exception -log cat:

07-22 09:51:36.791: e/androidruntime(13010): fatal exception: asynctask #1 07-22 09:51:36.791: e/androidruntime(13010): java.lang.runtimeexception: error occured while executing doinbackground() 07-22 09:51:36.791: e/androidruntime(13010):    @ android.os.asynctask$3.done(asynctask.java:299) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.futuretask$sync.innersetexception(futuretask.java:273) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.futuretask.setexception(futuretask.java:124) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.futuretask$sync.innerrun(futuretask.java:307) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.futuretask.run(futuretask.java:137) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.os.asynctask$serialexecutor$1.run(asynctask.java:230) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1076) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:569) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.lang.thread.run(thread.java:882) 07-22 09:51:36.791: e/androidruntime(13010): caused by: android.view.viewrootimpl$calledfromwrongthreadexception: original thread created view hierarchy can touch views. 07-22 09:51:36.791: e/androidruntime(13010):    @ android.view.viewrootimpl.checkthread(viewrootimpl.java:4634) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.view.viewrootimpl.invalidatechildinparent(viewrootimpl.java:867) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.view.viewgroup.invalidatechild(viewgroup.java:4066) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.view.view.invalidate(view.java:10193) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview.invalidateregion(textview.java:4375) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview.invalidatecursor(textview.java:4318) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview.spanchange(textview.java:7172) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview$changewatcher.onspanadded(textview.java:8759) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.text.spannablestringbuilder.sendspanadded(spannablestringbuilder.java:979) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.text.spannablestringbuilder.setspan(spannablestringbuilder.java:688) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.text.spannablestringbuilder.setspan(spannablestringbuilder.java:588) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.text.selection.setselection(selection.java:76) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.text.selection.setselection(selection.java:87) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.text.method.arrowkeymovementmethod.initialize(arrowkeymovementmethod.java:302) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview.settext(textview.java:3535) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview.settext(textview.java:3405) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.edittext.settext(edittext.java:80) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.widget.textview.settext(textview.java:3380) 07-22 09:51:36.791: e/androidruntime(13010):    @ com.example.test2.mainactivity$requestloginfromserver.doinbackground(mainactivity.java:113) 07-22 09:51:36.791: e/androidruntime(13010):    @ android.os.asynctask$2.call(asynctask.java:287) 07-22 09:51:36.791: e/androidruntime(13010):    @ java.util.concurrent.futuretask$sync.innerrun(futuretask.java:305) 07-22 09:51:36.791: e/androidruntime(13010):    ... 5 more 07-22 09:51:36.851: w/iinputconnectionwrapper(13010): showstatusicon on inactive inputconnection 07-22 09:53:22.261: d/activitythread(13141): handleresumeactivity pri:0 07-22 09:53:22.261: d/activitythread(13141): handleresumeactivity set pri:0 07-22 09:53:27.531: w/dalvikvm(13141): threadid=11: thread exiting uncaught exception (group=0x40d9a318) 07-22 09:53:27.561: e/androidruntime(13141): fatal exception: asynctask #1 07-22 09:53:27.561: e/androidruntime(13141): java.lang.runtimeexception: error occured while executing doinbackground() 07-22 09:53:27.561: e/androidruntime(13141):    @ android.os.asynctask$3.done(asynctask.java:299) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.futuretask$sync.innersetexception(futuretask.java:273) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.futuretask.setexception(futuretask.java:124) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.futuretask$sync.innerrun(futuretask.java:307) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.futuretask.run(futuretask.java:137) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.os.asynctask$serialexecutor$1.run(asynctask.java:230) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1076) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:569) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.lang.thread.run(thread.java:882) 07-22 09:53:27.561: e/androidruntime(13141): caused by: android.view.viewrootimpl$calledfromwrongthreadexception: original thread created view hierarchy can touch views. 07-22 09:53:27.561: e/androidruntime(13141):    @ android.view.viewrootimpl.checkthread(viewrootimpl.java:4634) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.view.viewrootimpl.invalidatechildinparent(viewrootimpl.java:867) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.view.viewgroup.invalidatechild(viewgroup.java:4066) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.view.view.invalidate(view.java:10193) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview.invalidateregion(textview.java:4375) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview.invalidatecursor(textview.java:4318) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview.spanchange(textview.java:7172) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview$changewatcher.onspanadded(textview.java:8759) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.text.spannablestringbuilder.sendspanadded(spannablestringbuilder.java:979) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.text.spannablestringbuilder.setspan(spannablestringbuilder.java:688) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.text.spannablestringbuilder.setspan(spannablestringbuilder.java:588) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.text.selection.setselection(selection.java:76) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.text.selection.setselection(selection.java:87) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.text.method.arrowkeymovementmethod.initialize(arrowkeymovementmethod.java:302) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview.settext(textview.java:3535) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview.settext(textview.java:3405) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.edittext.settext(edittext.java:80) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.widget.textview.settext(textview.java:3380) 07-22 09:53:27.561: e/androidruntime(13141):    @ com.example.test2.mainactivity$requestloginfromserver.doinbackground(mainactivity.java:111) 07-22 09:53:27.561: e/androidruntime(13141):    @ android.os.asynctask$2.call(asynctask.java:287) 07-22 09:53:27.561: e/androidruntime(13141):    @ java.util.concurrent.futuretask$sync.innerrun(futuretask.java:305) 07-22 09:53:27.561: e/androidruntime(13141):    ... 5 more 

caused caused by: android.view.viewrootimpl$calledfromwrongthreadexception: original thread created view hierarchy can touch views.. performing changes on ui non-ui thread. @ least line here (in asynctask doinbackground):

            string text = jobj.get("masterperosactive").tostring();             edt.settext(text); 

since using asynctask, why not perform ui changes in onpostexecute() method requestloginserver class change (only last lines touched):

public class requestloginfromserver extends asynctask<object, object, string> {     textview txt = (textview) findviewbyid(r.id.textview1);     edittext edt = (edittext) findviewbyid(r.id.edittext1);      @override     protected object doinbackground(object... params) {          httpclient httpclient = new defaulthttpclient();         httppost httppost = new httppost("http://shopstable.turkcell.com.tr/timmenu/getperosconfig.do");         httppost.setheader("content-type", "application/json");          try {              httpresponse response = httpclient.execute(httppost);             httpentity resentity = response.getentity();             = resentity.getcontent();         } catch (unsupportedencodingexception e) {             e.printstacktrace();         } catch (clientprotocolexception e) {             e.printstacktrace();         } catch (ioexception e) {             e.printstacktrace();             // strjson = null;         }         try {             bufferedreader reader = new bufferedreader(new inputstreamreader(is, "utf-8"), 8); // iso-8859-1 //             stringbuilder sb = new stringbuilder();             string line = null;             while ((line = reader.readline()) != null) {                 sb.append(line + "/n");             }             is.close();             strjson = sb.tostring();         } catch (exception e) {          }          try {             if (strjson != null) {                 jobj = new jsonobject(strjson);                 string text = jobj.get("masterperosactive").tostring();                 return text;              } else {                 jobj = null;             }         } catch (jsonexception e) {         }         return null;     }      protected void onpostexecute(string result) {          if(result != null) {              edt.settext(result);          } else {              // show message/label went wrong          }      } }