How to make a Swift String enum available in Objective-C?
From the Xcode 6.3 release notes (emphasis added):
Swift Language Enhancements
...
Swift enums can now be exported to Objective-C using the @objc attribute. @objc enums must declare an integer raw type, and cannot be generic or use associated values. Because Objective-C enums are not namespaced, enum cases are imported into Objective-C as the concatenation of the enum name and case name.
Here is work around if you really want to achieve the goal. However, you can access the enum values in objects that Objective C accepts, not as actual enum values.
enum LogSeverity : String {
case Debug = "DEBUG"
case Info = "INFO"
case Warn = "WARN"
case Error = "ERROR"
private func string() -> String {
return self.rawValue
}
}
@objc
class LogSeverityBridge: NSObject {
class func Debug() -> NSString {
return LogSeverity.Debug.string()
}
class func Info() -> NSString {
return LogSeverity.Info.string()
}
class func Warn() -> NSString {
return LogSeverity.Warn.string()
}
class func Error() -> NSString {
return LogSeverity.Error.string()
}
}
To call :
NSString *debugRawValue = [LogSeverityBridge Debug]
One of the solutions is to use the RawRepresentable
protocol.
It's not ideal to have to write the init and rawValue methods but that allows you to use this enum as usual in both Swift and Objective-C.
@objc public enum LogSeverity: Int, RawRepresentable {
case debug
case info
case warn
case error
public typealias RawValue = String
public var rawValue: RawValue {
switch self {
case .debug:
return "DEBUG"
case .info:
return "INFO"
case .warn:
return "WARN"
case .error:
return "ERROR"
}
}
public init?(rawValue: RawValue) {
switch rawValue {
case "DEBUG":
self = .debug
case "INFO":
self = .info
case "WARN":
self = .warn
case "ERROR":
self = .error
default:
return nil
}
}
}
Here's a solution that works.
@objc public enum ConnectivityStatus: Int {
case Wifi
case Mobile
case Ethernet
case Off
func name() -> String {
switch self {
case .Wifi: return "wifi"
case .Mobile: return "mobile"
case .Ethernet: return "ethernet"
case .Off: return "off"
}
}
}