iOS 13后获取wifi ssid 的问题

iOS 13 之后的系统，需要获取定位权限才能开启获取 SSID，另外要在XCode Signing&Capabilies中添加Access WiFi Information.

    <key>NSLocationAlwaysUsageDescription</key>
    <string></string>
    <key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
    <string></string>
    <key>NSLocationUsageDescription</key>
    <string></string>
    <key>NSLocationWhenInUseUsageDescription</key>
    <string></string>

class WiFiSSIDHelper: NSObject {    
    override init() {
        super.init()
    }
    
    func getWifiSSID() -> String? {
        if #available(iOS 13.0, *) {
            //用户明确拒绝，可以弹窗提示用户到设置中手动打开权限
            if CLLocationManager.authorizationStatus() == .denied {
                print("User has explicitly denied authorization for this application, or location services are disabled in Settings.")
                //使用下面接口可以打开当前应用的设置页面
                //[[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
                return nil
            }
            let cllocation = CLLocationManager()
            if !CLLocationManager.locationServicesEnabled() || CLLocationManager.authorizationStatus() == .notDetermined {
                //弹框提示用户是否开启位置权限
                cllocation.requestWhenInUseAuthorization()
                usleep(500)
                //递归等待用户选选择
                return getWifiSSID()
            }
        }

        var wifiName: String? = nil
        let wifiInterfaces = CNCopySupportedInterfaces()
        if wifiInterfaces == nil {
            return nil
        }
        let interfaces = wifiInterfaces as? [AnyHashable]
        for interfaceName in interfaces ?? [] {
            guard let interfaceName = interfaceName as? String else {
                continue
            }
            let dictRef = CNCopyCurrentNetworkInfo(interfaceName as CFString)

            if let dictRef = dictRef {
                let networkInfo = dictRef as? [AnyHashable : Any]
                print("network info -> (networkInfo ?? [:])")
                wifiName = networkInfo?[(kCNNetworkInfoKeySSID as String)] as? String
            }
        }
        return wifiName
    }
}