How to open an Activity from a java notification on android?

Question

How to open an Activity by clicking on the notification. The detail is that I want it to reopen again even if it is open in order to update the data of it. I’m using:

int icon = R.drawable.ic_launcher;
    long when = System.currentTimeMillis();
    NotificationManager notificationManager = (NotificationManager)
            context.getSystemService(Context.NOTIFICATION_SERVICE);
    Notification notification = new Notification(icon, message, when);

    String title = context.getString(R.string.app_name);

    Intent notificationIntent = new Intent(context, MainActivity.class);
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP |  Intent.FLAG_ACTIVITY_SINGLE_TOP);
    PendingIntent intent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
    notification.setLatestEventInfo(context, title, message, intent);
    notification.flags |= Notification.FLAG_AUTO_CANCEL;

    // Play default notification sound
    notification.defaults |= Notification.DEFAULT_SOUND;

    //notification.sound = Uri.parse("android.resource://" + context.getPackageName() + "your_sound_file_name.mp3");

    // Vibrate if vibrate is enabled
    notification.defaults |= Notification.DEFAULT_VIBRATE;
    notificationManager.notify(0, notification);  

Answer 1

PendingIntent.getActivity(context, 0, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);

The above code makes use of the flag UPDATE_CURRENT which updates instead of opening a new Activity, it will update the current Activity data. That is, the flag check if the intent and then will open it just updating the data.

Answer 2

PendingIntent notificationIntent = preparePendingIntent(context,stringValue,valueBoolean);

PendingIntent preparePendingIntent(Context context,String valueString,boolean valueBoolean) {
    Intent intent = new Intent(context, MainActivity.class);
    Bundle args = new Bundle();
    //Passando Valores para Activity
    args.putBoolean("Key", valueBoolean);
    args.putString("Key", valueString);

    intent.putExtras(args);

    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK |Notification.FLAG_ONGOING_EVENT);

    PendingIntent pendingIntent = PendingIntent.getActivity(0,
            context, 
            intent, 
            PendingIntent.FLAG_UPDATE_CURRENT);

    return pendingIntent;
}