Android: How do I avoid starting activity which is already in stack?

Question

Lets try to explain my question: I got an application and a service. The application is started with activity A. The service sends a broadcast that will let the application

Answer 1

You can use flag Intent.FLAG_ACTIVITY_NEW_TASK. If the activity is already running it will bring that to front instead of creating new activity.

If you add Intent.FLAG_ACTIVITY_CLEAR_TOP with this, then all the activities after this activity in the backstack will be cleared.