I have a class that does a complex calculation which may take a long time. I'd like to add a progress bar with Abort button. However, I would like to avoid mixing calculation code with GUI code if possible.

Are there any good design patterns for this?

CodePudding user response：

The relevant design pattern is the Observer pattern: your class doing a calculation is the "subject", it maintains a list of Observers, implementing a common Observer interface, and when its state changes (i.e. the amount of progress has changed), it notifies each observer via an update() call.