How to change your xml code if someone presses a button on the xml code in android development?

How to change your xml code if someone presses a button on the xml code in
android development?

I am making a mobile application for android using XML and JAVA.
How can I add another row (of stuff ) to this XML layout when someone
presses the button "add".
For example, if they click the button add on this layout.
http://gyazo.com/fe44f0ddbad62d1664a6f3cd8b4a55b9
It will become this: http://gyazo.com/9bc6b27aaf89226b0bcba8cb34c17f5f
So the important part is that the add button moves down, and I am able to
modify the XML file to display something new.