update RecyclerView with Android LiveData

Question

There are many examples how to push new list to adapter on LiveData change.

I\'m trying to update one row (e.g number of comments for post) in the huge list. It would be

Answer 1

Like @Lyla said, you should observe the whole list as LiveData in Fragment or Activity, when receive changes, you should set the whole list to the adapter by DiffUtil.

Fake code:

PostViewModel {
    LiveData> posts;  // posts comes from DAO or Webservice
}

MyFragment extends LifecycleFragment {
    PostAdapter postAdapter;

    ...

    void onActivityCreated() {
        ...
        postViewModel.posts.observer(this, (postList) -> {
            postAdapter.setPosts(postList);
        }
    }       
}

PostAdapter {
    void setPosts(List postList) {
        DiffUtil.DiffResult result = DiffUtil.calculateDiff(new DiffUtil.Callback() {...}
        ...
    }
}