代码：

class CheckVpnConnectionStatus {

  /// 如果设备具有 VPN 连接，返回 true
  static Future<bool> isVpnActive() async {
    bool isVpnActive;
    List<NetworkInterface> interfaces = await NetworkInterface.list(includeLoopback: false, type: InternetAddressType.any);
    interfaces.isNotEmpty ? isVpnActive = interfaces.any((interface) =>
    interface.name.contains("tun") || interface.name.contains("ppp") || interface.name.contains("pptp")) : isVpnActive = false;
    return isVpnActive;
  }
}

使用：

if (await CheckVpnConnectionStatus.isVpnActive()) {
  // existence vpn connect
}