QString changyanlong_xiaolaohu::IpAddress() {
    QString strIpAddress;
    QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();

    // find ipv4 address
    int nListSize = ipAddressesList.size();
    for (int i = 0; i < nListSize; ++i)
    {
           if (ipAddressesList.at(i) != QHostAddress::LocalHost &&
               ipAddressesList.at(i).toIPv4Address()) {
               strIpAddress = ipAddressesList.at(i).toString();
               break;
           }
     }

     // if v4 is none , find local ip address
     if (strIpAddress.isEmpty())
        strIpAddress = QHostAddress(QHostAddress::LocalHost).toString();
     return strIpAddress;
}