無法下標'[NSObject：AnyObject]類型的值？” 索引類型為'String'的Swift錯誤

Question

我的鱈魚就是那個，這個錯誤出現在課程的最后一行，我該怎么做才能解決呢？

public class SSID {
            class func fetchSSIDInfo() -> String {
                var currentSSID = ""
                if let interfaces = CNCopySupportedInterfaces() {
                    for i in 0..<CFArrayGetCount(interfaces) {
                        let interfaceName: UnsafeRawPointer = CFArrayGetValueAtIndex(interfaces, i)
                        let rec = unsafeBitCast(interfaceName, to: AnyObject.self)
                        let unsafeInterfaceData = CNCopyCurrentNetworkInfo("\(rec)" as CFString)
                        if unsafeInterfaceData != nil {
                            let interfaceData = unsafeInterfaceData! as Dictionary!
                            currentSSID = interfaceData?["SSID"] as String
                        }
                    }
                }
                return currentSSID
            }
        }

Answer 1

使用下標的唯一行是：

let interfaceData = unsafeInterfaceData! as Dictionary!
currentSSID = interfaceData?["SSID"] as String

使用這樣的字符串進行訪問： interfaceData?["SSID"]要求您以不同的方式定義字典，當前字典被聲明為[NSObject: AnyObject]但要使用String下標，則必須為[String: AnyObject]

嘗試將此行更改為：

let interfaceData = unsafeInterfaceData! as [String: AnyObject]

注意：如果讓用而不是用!強制展開，則最好使用!

Answer 2

你可以試試

if  let interfaceData = unsafeInterfaceData! as? [String:Any]
{
    currentSSID = interfaceData["SSID"] as? String
}