Delegation Pattern in Swift
Article Summary
Williams Perdana from Blibli.com uses a CEO analogy to explain one of Swift's most powerful patterns. Just like a CEO delegates to department heads, your code can delegate responsibilities to keep things clean and maintainable.
This practical guide breaks down the delegation pattern in Swift using a real-world book list app example. Perdana walks through how protocols enable view controllers to communicate without tight coupling, making code more reusable and testable.
Key Takeaways
- Protocols define blueprints that classes conform to, enabling polymorphism in Swift
- Delegation lets one VC trigger actions in another without direct dependencies
- Real example: InputTitleVC reuses save logic across multiple view controllers
- Setting delegate = self passes implementation responsibility to the conforming class
The delegation pattern keeps Swift code loosely coupled by letting objects hand off responsibilities through protocol conformance instead of direct references.
About This Article
Williams Perdana ran into a scalability issue. Reusing InputTitleVC across multiple view controllers meant creating separate variables for each controller type. Beyond 10+ view controllers, this approach became unmaintainable.
Perdana used Swift protocols to define a blueprint for saving methods. Any class that conformed to the protocol could provide its own implementation through delegation, without needing direct dependencies.
InputTitleVC could now be reused across FictionalBooksTableVC and EducationalBooksTableVC with different save implementations. This eliminated the need for multiple controller-specific variables and reduced code coupling.