ios - 'subscript(_:)' 的使用不明确

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()



        }
    }

此错误会定期显示。我已将 if let content = data{ 更改为 if let content = data["content"] as? Double{ 但它显示另一个错误，即“可选类型‘数据’的值？”必须解包以引用包装基类型“数据”的成员“下标””。我在包括 stackoverflow 在内的许多网站上看到了一些相关查询，但它们是 MacOS，但我在 WatchOS 上工作。任何人都请帮忙!

Answer 1

JSON 对象从不未指定AnyObject。如果您期望字典将其转换为字典

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

这修复了错误，因为编译器现在知道真实类型。

永远不要指定 .mutableContainers。该选项在 Swift 中无效