android - Popup window in any app -

i want popup dialog @ specific time in app code :

 public class testpopdialog extends activity { /** called when activity first created. */ private handler mhandler = new handler(); @override public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.main);       mhandler.postdelayed(mupdatetimetask, 1000);    } private runnable mupdatetimetask = new runnable() {        public void run() {            alertdialog d = new alertdialog.builder(testpopdialog.this)             .settitle("tanchulai")             .setmessage("bucuo de tanchulai")              .create();          d.getwindow().settype(windowmanager.layoutparams.type_system_alert);         d.show();             }     };  } 

it give me

12-03 10:12:18.162: error/androidruntime(571): android.view.windowmanager$badtokenexception: unable add window android.view.viewroot$w@43dd71c0 -- permission denied window type 

what permission if delete d.getwindow().settype(windowmanager.layoutparams.type_system_alert); app correct.....

add permission manifest:

android.permission.system_alert_window