flutter 自带的dart:io 库就可以支持获取设备的 ipv4 和ipv6地址.
flutter 获取的ipv6地址字符串跟iOS 原生获取的ipv6地址,稍微有区别:

iOS 
ipv4:  192.168.3.81
ipv6: fe80::2:7cc7:ca39:fe4d

flutter:
IPv4 address: 192.168.3.81
IPv6 address: fe80::2:7cc7:ca39:fe4d%en0 

可以看到 flutter获取的 ipv6 最后会 拼上 %en0,为了保证数据的一致性,所以需要用空替换
tempIpv6 = tempIpv6.replaceAll("%en0", "");

import 'dart:io';
import 'package:flutter/foundation.dart';

class IpV4AndIpV6Tool {
  static Future<void> getIpv4AndIpV6Addresses(
      Function(String ipv4Address, String ipv6Address)
          didClickConfirmBtnAction) async {
    String tempIpv4 = "";
    String tempIpv6 = "";
    try {
      // 获取所有网络接口信息
      List<NetworkInterface> interfaces = await NetworkInterface.list(
        includeLoopback: true, // 是否包含回环接口
        includeLinkLocal: true, // 是否包含链路本地接口（例如IPv6的自动配置地址）。
        type: InternetAddressType.any,
      );

      // 遍历所有网络接口
      for (var interface in interfaces) {
        // check if interface is en0 which is the wifi conection on the iphone
        if (interface.name != 'en0') {
          continue;
        }
        print('Interface name: ${interface.name}');
        // 遍历接口的地址
        for (var address in interface.addresses) {
          if (address.address.isNotEmpty) {
            if (address.type == InternetAddressType.IPv4) {
              tempIpv4 = address.address;
              if (kDebugMode) {
                print('IPv4 address: $tempIpv4');
              }
            } else if (address.type == InternetAddressType.IPv6) {
              tempIpv6 = address.address;
              if (tempIpv6.contains("%en0")) {
                tempIpv6 = tempIpv6.replaceAll("%en0", "");
              }

              if (kDebugMode) {
                print('IPv6 address: $tempIpv6');
              }
            }
          }
        }
      }
    } catch (e) {
      print('Failed to get IP addresses: $e');
    } finally {
      didClickConfirmBtnAction(tempIpv4, tempIpv6);
    }
  }
}