First of all, thank you for this post. It’s very informative and useful.
My question is about framework independence for presenters. What if I need to run some simple validation in my presenter, like check if the email is valid an the password is not empty and I want to use handy TextUtils class? It would instantly make my presenter framework-aware and break the entire idea, but at the same time I hardly imagine implementing TextUtils myself just to not break the pattern. The only way I see is using some 3rd-party text utils library, like apache-commons which is Android-independent but the questions remains open. What do you use for text validations in your presenters?