Protocol Oriented Programming in Swift: Advanced Applications

The original article – Protocol Oriented Programming in Swift: Is it better than Object Oriented Programming? – was published on appcoda.com.

Introduction

We’re going to talk in-depth about protocol-oriented programming (POP) using Swift 4 in this article. This post is the second and final article in a two part series. If you haven’t read the first, introductory article, please do so before continuing onwards. Today, we’ll: discuss why Swift is considered a “protocol-oriented” language, compare POP and object-oriented programming (OOP), compare value semantics and reference semantics, consider local reasoning, implement delegation with protocols, use protocols as types, use protocol polymorphism, review my real-world POP Swift code, and finally, discuss why I’ve not bought 100% into POP. Download the source code from the article so you can follow along: There are 2 playgrounds and one project on GitHub, both in Xcode 9 format and written in Swift 4.

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Polymorphism in Swift 3: manipulate multiple related controls with one IBOutlet and one IBAction

How would you enable or disable multiple user interface controls using one IBOutlet and one IBAction? For example, you might need to disable a UITextBox and UISegmentedControl because a user’s login has expired. Perhaps a user hasn’t filled in some required fields on a form, so you want to disable several buttons. Watch the following video to see how I built a Swift 3 app to use a UISwitch to enable or disable four controls all at one time — and I demonstrated the object-oriented programming (OOP) principle of polymorphism:

Refresh your memory about OOP and inheritance.

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