NEW! Master Swift design patterns with my latest book! >>

What does override mean?

Paul Hudson       @twostraws

The override is used when you want to write your own method to replace an existing one in a parent class. It's used commonly when you're working with UIViewControllers, because view controllers already come with lots of methods like viewDidLoad() and viewWillAppear(). When you want to override these default methods, you need to specify this with the override keyword.

Now, you might be wondering why the override keyword is even needed, but it's really about ensuring your code is safe – if you write a method and accidentally name it the same as something that already exists, Xcode will simply refuse to build your app until you add in the override keyword. Similarly, if you use override on a method that doesn't override something that already exists, Xcode will refuse to build.

Available from iOS 7.0

Did this solution work for you? Please pass it on!

Other people are reading…

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.

Love Hacking with Swift?

Get all 40 projects in PDF and HTML: buy the Hacking with Swift book! It contains over 1300 pages of hands-on Swift coding, and will really help boost your iOS career

MASTER SWIFT NOW
Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns Buy Practical iOS 11 Buy Swift Coding Challenges Buy Server-Side Swift (Vapor Edition) Buy Server-Side Swift (Kitura Edition) Buy Hacking with macOS Buy Advanced iOS Volume One Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with Swift Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let me know!

Click here to visit the Hacking with Swift store >>