Android : Android TimerTask won't stop using "timer.cancel()", when onPause

I was reading a number of posts here about stoping a Timer using the cancel(); method, but no matter how I try, the timer keeps running in the background after onPause() occurs.

(Note that I am executing an AsyncTask inside the timer, I know that it was meant to be run only once, but I am afraid that if I run the AsyncTask on the main thread it will hang up my main activity.)

So why the timer won't stop onPause() ?

} //end on create


        @Override
        protected void onPause() {      
            super.onPause();            
            this.timer.cancel();
            this.timer.purge();

        }

        @Override
        protected void onResume() {     
            super.onResume();
            callAsynchronousTask();
        }

        public void callAsynchronousTask() {            
            final Handler handler = new Handler();
            timer = new Timer();
            TimerTask doAsynchronousTask = new TimerTask() {       
                @Override
                public void run() {
                    handler.post(new Runnable() {
                        public void run() {       
                            try {
                                MyTask task = new MyTask();
                                task.execute("Param 1", "Param 2", "Param 3");  
                            } catch (Exception e) {
                          }
                        }
                    });
                }
            };
            timer.schedule(doAsynchronousTask, 0, 2000);    

        }