Android dynamic IP


I want to make a app who have a dynamic IP:
I would like that you can enter a link when you lanch the app.
After you enter link, the app receive information about the ip adress of the computer who receive informations send by the app.
If it’s work it could work for everybody

It’s important to mentionned that the phone and the computer are in 2 different country, that’s why I want to use a website adress cause I don’t know the ip adress in advance…

I really don’t know how to do that if u have some, github, forum, …
That’s could be really great.

I hope to be clear and sorry for my bad english,