Swift获取当前网络状态Wifi/5G/4G/3G/2G

通过Swift获取当前网络状态

通过第三方库Alamofire获取网络状态只能获取到ethernetOrWiFi、cellular、notReachable、unknown这几种网络状态，不能准确的获取到Wifi/5G/4G/3G/2G状态，于是通过系统SystemConfiguration跟CoreTelephony库来实现获取当前对应的网络状态，实现代码如下：

import CoreTelephony
import SystemConfiguration

/// 无网络返回字样
private static var notReachable: String {
        get {
            return "notReachable"
        }
  }

/// 获取网络类型
private static func getNetworkType() -> String {
        var zeroAddress = sockaddr_storage()
        bzero(&zeroAddress, MemoryLayout<sockaddr_storage>.size)
        zeroAddress.ss_len = __uint8_t(MemoryLayout<sockaddr_storage>.size)
        zeroAddress.ss_family = sa_family_t(AF_INET)
        let defaultRouteReachability = withUnsafePointer(to: &zeroAddress) {
            $0.withMemoryRebound(to: sockaddr.self, capacity: 1) { address in
                SCNetworkReachabilityCreateWithAddress(nil, address)
            }
        }
        guard let defaultRouteReachability = defaultRouteReachability else {
            return notReachable
        }
        var flags = SCNetworkReachabilityFlags()
        let didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags)
        
        guard didRetrieveFlags == true,
              (flags.contains(.reachable) && !flags.contains(.connectionRequired)) == true
        else {
            return notReachable
        }
        if flags.contains(.connectionRequired) {
            return notReachable
        } else if flags.contains(.isWWAN) {
            return self.cellularType()
        } else {
            return "WiFi"
        }
    }
    
    /// 获取蜂窝数据类型
    private static func cellularType() -> String {
        let info = CTTelephonyNetworkInfo()
        var status: String
        
        if #available(iOS 12.0, *) {
            guard let dict = info.serviceCurrentRadioAccessTechnology,
                  let firstKey = dict.keys.first,
                  let statusTemp = dict[firstKey] else {
                return notReachable
            }
            status = statusTemp
        } else {
            guard let statusTemp = info.currentRadioAccessTechnology else {
                return notReachable
            }
            status = statusTemp
        }
        
        if #available(iOS 14.1, *) {
            if status == CTRadioAccessTechnologyNR || status == CTRadioAccessTechnologyNRNSA {
                return "5G"
            }
        }
        
        switch status {
        case CTRadioAccessTechnologyGPRS,
            CTRadioAccessTechnologyEdge,
        CTRadioAccessTechnologyCDMA1x:
            return "2G"
        case CTRadioAccessTechnologyWCDMA,
            CTRadioAccessTechnologyHSDPA,
            CTRadioAccessTechnologyHSUPA,
            CTRadioAccessTechnologyeHRPD,
            CTRadioAccessTechnologyCDMAEVDORev0,
            CTRadioAccessTechnologyCDMAEVDORevA,
        CTRadioAccessTechnologyCDMAEVDORevB:
            return "3G"
        case CTRadioAccessTechnologyLTE:
            return "4G"
        default:
            return notReachable
        }
    }