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

I think you need to make your activity B singleInstance that if it's already create you don't want to create again, that is launch mode of the activity can be defined in manifest android:launchMode that defines how the activity will be instanciated.

in your case use android:launchMode="singleInstance"