That's not how maps work, they don't really have a...

# getting-started

[karelpeeters]

That's not how maps work, they don't really have an order most of the time.

[sqia09]

So I should use an expandable list, right?
I found this link: https://bignerdranch.github.io/expandable-recycler-view/
what do you think? or if you got a better resource then please share.

[karelpeeters]

That's an android layout component, not really a data structure. You could use a LinkedHashMap<String, List<String>>.