'下标(_:)'的歧义使用

Question

func getCurrency()
    {

        let myLink:[String] = ["url1", "url2", "url3"]
        for link in myLink{
            let url = URL(string: link)
            let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
                if error != nil{
                    print("ERROR")
                }
                else{
                    if let content = data{
                        do{
                            if link == myLink[0]{
                                let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject

                                if let ratesusd = myJson["INR_USD"] as? Double{
                                    self.usdValue = ratesusd
                                }
                            }
                            else if link == myLink[1]{
                                let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject

                                if let rateseuro = myJson["INR_EUR"] as? Double{
                                    self.euroValue = rateseuro
                                }
                            }
                            else if link == myLink[2]{
                                let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject

                                if let ratespound = myJson["INR_GBP"] as? Double{
                                    self.poundValue = ratespound
                                }
                            }


                        }
                        catch{

                        }
                    }
                }
                }
                task.resume()



        }
    }

This error regularly displays. I have changed the if let content = data{ to if let content = data["content"] as? Double{ if let content = data["content"] as? Double{ but it show another error ie, "Value of optional type 'Data?' must be unwrapped to refer to member 'subscript' of wrapped base type 'Data'". I have seen some related queries on many sites including stackoverflow but they are of MacOS but i am working on WatchOS. Anyone please help!

Answer 1

A JSON object is never unspecified AnyObject . If you expect a dictionary cast it to dictionary

let myJson = try JSONSerialization.jsonObject(with: content) as! [String:Any]

This fixes the error because the compiler now knows the real type.

And never specify .mutableContainers . The option has no effect in Swift