android - displaying progress dialog inside runOnUiThread in fragment -

i have simple android application should display progress dialog when press 'activate' button. basically, when press 'activate', app display progress dialog while detecting nearby sensors. update progress dialog message while detects sensors. following code implemented inside fragment.

but code not display progress dialog. don't see when press 'button'. seems frozen.

    @override     public void onclick( view v) {     v.setenabled(false);     activatebutton.setenabled(true);     final activity activity = getactivity();     final progressdialog pd = new progressdialog(activity);     activity.runonuithread(new runnable() {         @override         public void run() {             pd.settitle("activating...");             pd.setmessage("please wait...");             pd.setcancelable(false);             pd.setindeterminate(false);             pd.show();              int count = 1;             pd.setmessage("detecting sensors...\n");             while (true) {                 if (count >= 10) {                     break;                 }                 count++;                 try {                     pd.setmessage("detected " + count + "=" + " sensor. \n");                     thread.sleep(1000 * 1);                 } catch (interruptedexception e) {                     e.printstacktrace();                 }             }             pd.dismiss();         }     }); 

based on comment, changed this.

        asynctask<void, void, void> task = new asynctask<void, void, void>() {         progressdialog pd;          @override         protected void onpreexecute() {              pd = new progressdialog(getactivity());             pd.settitle("activating...");             pd.setmessage("please wait...");             pd.setcancelable(false);             pd.setindeterminate(false);             pd.show();         }          @override         protected void doinbackground(void... arg0) {             int count = 1;             pd.setmessage("detecting sensors...\n");             try {                 thread.sleep(1000 * 1);             } catch (interruptedexception e1) {                 //             }             stringbuffer txt = new stringbuffer();             txt.append(".....");             while (true) {                 if (count >= 10) {                     break;                 }                 count++;                 pd.setmessage("detected " + count + "=" + " sensor. \n");             }              return null;         }          @override         protected void onpostexecute(void result) {             if (pd != null) {                 pd.dismiss();                 activatebutton.setenabled(true);             }         }      };     task.execute((void[]) null); 

but when code runs, error in line (pd.setmessage("detected " + count + "=" + " sensor. \n");).

caused by: android.view.viewrootimpl$calledfromwrongthreadexception: original thread created view hierarchy can touch views.

it helpful if can point goes wrong.

thanks.

you updating view background thread. method 'doinbackground' should call 'publishprogress' mehtod update progress dialog in 'onprogressupdate' (which execute in ui thread). check code below:

   new asynctask<void, string, void>() {         public progressdialog mprogress;          @override         protected void onpreexecute() {             mprogress = progressdialog.show(getcontext(), "progress", "please wait", true);         }          @override         protected void doinbackground(void... params) {             try {                 thread.sleep(1000);                 publishprogress("progress 1");                 thread.sleep(2000);                 publishprogress("progress 2");                 thread.sleep(2000);             } catch (interruptedexception e) {                 e.printstacktrace();             }             return null;         }          @override         protected void onpostexecute(void avoid) {             mprogress.dismiss();         }          @override         protected void onprogressupdate(string... values) {             mprogress.setmessage(values[0]);         }     };