How create notification topic for Firebase and use this?

Question

I can create notifications for single user and for all users in my app, but I can't understand and find information about notification with create topic. For this need create separate service and how do my topics dynamic?

Answer 1

There is no need to create a service when you want to subscribe to a topic. Just call anywhere in your app:

FirebaseMessaging.getInstance().subscribeToTopic("news");

Also see the section Subscribe the client app to a topic in the Firebase documentation.