CODEWITHSUNDEEP
swiftenumsprotocolsassociated-value
ShayneFCF
ShayneFCF

Reputation: 1

Swift Enum How to conform to a protocol's variables' set & get?

my code:

public protocol ApiRequestBaseObjProtocol {
    var param:[String:Any] { get set }
    var path:String {get}
}

extension ApiRequestBaseObjProtocol {
    var param: [String : Any] {
        get {
            var key = "\(self.path)"
            return (objc_getAssociatedObject(self, &key) as? [String : Any]) ?? [:]
        }
        set(newValue) {
            var key = "\(self.path)"
            objc_setAssociatedObject(self, &key, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }
}

enum MeApi : ApiRequestBaseObjProtocol {
    public var path: String {
        return "test/api/xxx"
    }
}

at param get{} method : objc_getAssociatedObject(self, &key) aways be nil. I want to know why? thank you!!

Upvotes: 0

Views: 349

Answers (1)

juhan_h
juhan_h

Reputation: 4011

You are creating two separate keys so your &key points to two separate things in getter and setter.. Try creating your key as a static constant. Per NSHipster:

It is often recommended that they key be a static char—or better yet, the pointer to one. Basically, an arbitrary value that is guaranteed to be constant, unique, and scoped for use within getters and setters:

Upvotes: 1

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