Set borders for an expanded group item using ExpandableListView

Question

I'm trying to find a way of creating a material-styled ExpandableListView, and I'm using the example located at the material design website. The example I'm following is:

I'm trying to replicate the borders that appear at the top and bottom of the group when the group is expanded, but I don't know where to start.

Can you help?

Kurland

I have the same issue. Did you manage to find a solution? – Broccoli