Bring application back to front

My application is a timer with alarm type app. When the timer expires i would like to bring the app's main activity back into view, if the user has navigated away, but the app is still running.

I show where i would like to place the necessary code:

   public class MyCount extends CountDownTimer {
        public MyCount(long milli开发者_运维技巧sInFuture, long countDownInterval) {
          super(millisInFuture, countDownInterval);
        }

        public void onFinish() {

         /** code here to bring the app back to the front / top of stack, in its current state */


         timeDisplay.setText("Expired.!");
         ReminderFlashingScreen.setVisibility(View.GONE);
         statustab.setBackgroundResource(R.drawable.redtab);
         seeker.setProgress(0);
         reset.setBackgroundResource(R.drawable.resetbtnoff);
         playExpiredAlarm(); 
         alarmAnimation.start();
         flasher.setVisibility(View.VISIBLE);
         StopAlarmButtonAnimation.start();
         StopAlarmButton.setVisibility(View.VISIBLE);
         expired = true;
        }

        public void onTick(long millisUntilFinished) {
            remindertimepref = prefs.getString("reminderTime", "<unset>");
            remindtime = Integer.parseInt(remindertimepref.trim());
            timeDisplay.setText(formatTime(millisUntilFinished));
            seeker.setProgress((int) (millisUntilFinished / 1000 / 60 ) + 1);
            if (used == true){
                reminder_time = ((int) (millisUntilFinished / 1000));
                if (reminder_time == remindtime){
                    reminderalarm();
                    used = false;
                    }
                }

          }
    }

For me it was this:

Intent intent = new Intent(Application.getContext(), AbstractFragmentActivity.instance.getClass());
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
intent.addFlags(Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
intent.addFlags(Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
Application.getContext().startActivity(intent);

See http://developer.android.com/guide/appendix/faq/framework.html#4:

How can I check if an Activity is already running before starting it?

The general mechanism to start a new activity if its not running— or to bring the activity stack to the front if is already running in the background— is the to use the NEW_TASK_LAUNCH flag in the startActivity() call.

You should put your timer in a Service, that way you're assured that Android won't kill your application while it's in background. (You can put your whole MyCount class in a service).

From the service you can always bring your application (Activity) to the front:

Intent intent = new Intent(getBaseContext(), TimerActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
startActivity(intent);