The application Sipnetic can make calls or text messages.
Sipnetic also has good functionality for handling contancts, and it is easy to create new SIP contacts.
There is also a feature for recording short messages and sending to a receiver, but many other sip phones are not able to receive these messages.
The application has a number of predefined SIP services, so for any of these, the configuration is very simple.
One of these is sip2sip.info, so an easy way to test the application is to create a free account on sip2sip.info,
and then configure Sipnetic with that account.
The application can be downloaded from Google play
Here are screenshots for the configuration of the application with sip2sip.info using TLS: