How to change the color of action programmatically

[philxws692]

Hello,
it's not really an issue it's more a question, because I didnn't find a way to change the color of the action button.
I want to do an application which connects to a bluetooth device, and when it's disconnected the button should show "connect" with green background and when it's connected it should show "disconnect" with red background.
I could change the action text so far so good.
But how do I change the background color programmatically?

Greetings
Philipp