How to maintain state of object throughout the app and change the UI at the same time

I'm developing an app having HomeFragment which displays posts of the user you are following. Now each post is having Like and Comment option and when you click on user profile pic or name, it will redirect you to his/her profile which again displays all his/her posts. Now again if you click on one of the post it will redirect you to post detail screen which implements ViewPager where you can change the post by swapping left or right.

My question is every post has Like and Comment option with Like and Comment count, if you like any one post then it should reflect at all the activities(Home, User profile and post detail).

Currently I'm handling all these using startActivityForResult and onActivityResult (eg: if you like post at position 2 and when you click back button then I'm sending that position with new count and notifying that particular position with new like count at HomeFragment) which is very confusing and I think is not the proper solution.

Is there any Design Pattern or any other mechanism to handle this?

If you didn't get my question then let me know, I'll elaborate it more.

Thank you.