how to read Memory data from an android app

I'd like to get some numerical data from an app, but they are not stored as files like db. I know there are some memory hack apps for changing in game values although I do not know how they work. I am looking for similar features but I don't need to change anything.

The app I am trying to write just reads some data from a specific app and do some background calculation based on that. If this is not possible, I would need to get information by reading the screen(for example get pixel color), but this seems to be very cumbersome task for getting many data.

Is there a way of achieving this?

Thanks.

EDIT: I'd assume I would need a root permission for this?

from how to read Memory data from an android app