Create a color function

Create a color function

I need your help to make a color function. I'd like to create something
like this
I've an edittext and I want to put in color part of string , but with a
special input example :
if the user type : ^1Hi ^2Stack^3Over^4Flow !
"Hi" = red color , "Stack" = green color , "Over" = blue color and "Flow"
= orange color.
how to do this?