if (flag == false) {
                        counter = new MyCount(720000, 1000);//360000
                        counter.start();
                    } else {
                        counter.cancel();
                        counter = new MyCount(millisUntilFinishedVariable, 1000);
                        counter.start();
                    }




public class MyCount extends CountDownTimer {

        public MyCount(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        @Override
        public void onFinish() {
            titleTextView.setText("Time out");
            tv_mins.setText("");
            final Dialog dialog = new Dialog(getMyActivityContext());
            dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
            Window window = dialog.getWindow();
            dialog.setContentView(R.layout.custom_dialog);
            window.setGravity(Gravity.CENTER);
            window.setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.WRAP_CONTENT);
            dialog.getWindow().getAttributes().windowAnimations = R.style.PauseDialogAnimation;
            dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
            dialog.setCancelable(true);

            TextView textView = (TextView) dialog.findViewById(R.id.text);
            TextView btnDismis = (TextView) dialog.findViewById(R.id.txt_ok);
            // textView.setGravity(Gravity.CENTER);
            textView.setText("Your session timed out. Please try again");
            dialog.setCanceledOnTouchOutside(false);
            dialog.show();
            btnDismis.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    finish();
                    dialog.dismiss();
                }
            });//TextView object should be defined in onCreate*/
            flag = false;
        }

        @Override
        public void onTick(long millisUntilFinished) {
            millisUntilFinishedVariable = millisUntilFinished;
            flag = true;
            String minsec = String.format("%02d:%02d", TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished), TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished)));

            titleTextView.setText(minsec);// This will be called every Second.
            tv_mins.setText("MINS LEFT");
        }
    }