How to start a timer in the background?

Question

Java

The task is this. There is an application in which fragment1 and fragment2 are present. Fragment1 has a timer that randomizes messages and displays them in the RecyclerView and in the BottomNavigationView - the counter of these same messages. Everything works fine until fragment2 opens. The timer stops working and updates the counter. Displaying the timer in the activity is not an option, because. RecyclerView cannot be updated from activity. How to make the timer work with any open fragment, where to put it?

Answer 1

keep the timer inside the ViewModel and network the value of the timer in LiveData, and from the fragment just subscribe to LiveData

Answer 2

Move timer to service