#include <QHostAddress>
#include <QNetworkInterface>
#include <QHostInfo>
QString localHostName = QHostInfo::localHostName();
QHostInfo info = QHostInfo::fromName(localHostName);
foreach(QHostAddress address, info.addresses())
{
if (address.protocol() == QAbstractSocket::IPv4Protocol)
ui->lineEdit->setText(address.toString());
}