Synchronizing parcelable state between Activities?

Question

I have Parcelable object that holds a query and offset to web API.

Then I have two Activities:

Activity A with a list and Activity B with a ViewPager. User navigates from Activity A to B, and Parcelable is passed in Intent. In Activity A query is persisted using onSaveInstanceState. (initial offset is 0 )

Inside Activity B activity user can swipe and offset can be increased. (offset increased to 20 )

Then user can navigate back to Acitvity A with list. In Activity A query is restored from savedInstanceState. ('offset` is 0 but should be 20 )

What is the best way to maintain such offset state between those two Activities? I want to avoid saving it to shared preferences.

Answer 1

You can start Activity B 'forResult', and when navigating back to Acivity A, set the result including the offset, so you can access it in Activity A in onAcivityResult() And refresh the value accordingly...