How to properly organize the interaction of ui and business logic?

Question

Software design

There is ui. Button and progress bar. By clicking on the button, a large number of files should be copied and the copy progress should be displayed.
Pressing the button calls the on_button_clicked() method, the method calls the FileCopier.copy_files() object method.
The dumbest thing you can do is call the parent progress bar update method in the copy_files() method.
How to smartly update ui progress bar from business logic?

Answer 1

The copy_files() method should provide information on the progress of copying by calling a function (callback) or sending an event (event) (depending on the programming language)