android - Resume application and stack from notification

Question

I want to resume my app from a status bar notification in the exact same manner as when the user taps its icon in the launcher.

That is: I want the stack to be in the same state as it was before the user left it.

The problem when setting a pending intent on the notification is that it always targets a specific activity. I don't want this. I need to resume the application just as the launcher does.

So if the user is in activity A, I want to resume activity A. If he has launched activity B from activity A, then I want B to be displayed when the user taps the notification, and the stack to be restored so that A gets resumed when the user taps the back button in B.

There are couple of other questions of questions with similar titles, but none address my problem.

Answer 1

Just use the same intent filters as Android uses when it launches the app:

final Intent notificationIntent = new Intent(context, YourActivity.class);
notificationIntent.setAction(Intent.ACTION_MAIN);
notificationIntent.addCategory(Intent.CATEGORY_LAUNCHER);
notificationIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

As the Intent you created to open your Activity from the notification bar is the same as Android used for launching your app, the previously opened Activity will be shown instead of creating a new one.