Conclusion

Let’s sum up what you learnt in this lesson:

• Inheritance and polymorphism enable you to create flexible, reusable code.
• In this lesson, you created a PublicDomainObject subclass of MuseumObject.
• It has a property — primaryImageSmall — that isn’t in the parent class, so you defined its init method to set this property and call the parent’s init.
• You redefined showImage(), then called this method from a MuseumObject and from a PublicDomainObject.
• Each object behaved according to its type: The MuseumObject used SFSafariViewController, and the PublicDomainObject used MuseumObjectView