What is the @objcMembers attribute?

Paul Hudson    February 12th 2018    @twostraws

By default Swift generates code that is only available to other Swift code, but if you need to interact with the Objective-C runtime – all of UIKit, for example – you need to tell Swift what to do.

If you just want to expose a single method or property, you can mark that method using the @objc attribute. However, if you want all methods in a class to be exposed to Objective-C you can use a shortcut: the @objcMembers keyword:

@objcMembers class MyController: UIViewController {
    func login() {

    }
}

In that code, the login() method will automatically be exposed to Objective-C in the same way as if it had been marked with @objc, because the whole class it’s inside is marked with @objcMembers.

Available from iOS 8.0

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

Tweet

Other people are reading…

• How to detect when the system is under pressure and you should reduce your work
• What is a protocol associated type?
• How to make a number positive using abs()
• What is a functor?
• What are sets?

About the Swift Knowledge Base

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