After installing Xcode 9 and migrating to Swift 4 from Swift 3 , @objc inference warning comes like below:
If you introduce new methods or variables to a Swift class, marking them as @objc exposes them to the Objective-C run time. This is necessary when you have Objective-C code that uses your Swift class, or, if you are using Objective-C-type features like Selectors.
This is the best way for converting your code so that compiler doesn't complain.
This will automatically add @objc to ALL the functions and variables in the class.
This is a easy way but it increases the application size by exposing functions that did not need to be exposed.
Official Documentation
The use of Swift 3 @objc inference in Swift 4 mode is deprecated. Please address deprecated @objc inference warnings, test your code with “Use of deprecated Swift 3 @objc inference” logging enabled, and then disable inference by changing the “Swift 3 @objc Inference” build setting to “Default” for the “AppName” target.
If you introduce new methods or variables to a Swift class, marking them as @objc exposes them to the Objective-C run time. This is necessary when you have Objective-C code that uses your Swift class, or, if you are using Objective-C-type features like Selectors.
Fix compiler Errors:
We can fix this @objc inference warning by using two ways.Solution 1:
One is to use @objc on each function or variable that needs to be exposed to the Objective-C run time as follow:@objc func getSomeData() {
}
This is the best way for converting your code so that compiler doesn't complain.
Solution 2:
Second one is to add @objcMembers by a Class declaration as follow:@objcMembers
class Photo {
}
This will automatically add @objc to ALL the functions and variables in the class.
This is a easy way but it increases the application size by exposing functions that did not need to be exposed.
Official Documentation
