[angular-ui] How to detect current state within directive

The use of ui-sref-active directive that worked for me was:

<li ui-sref-active="{'active': 'admin'}">
    <a ui-sref="admin.users">Administration Panel</a>
</li>

as found here under the comment labeled "tgrant59 commented on May 31, 2016".

I am using angular-ui-router v0.3.1.