用正则表达式就可以了!如下设置IP_lineEdit的输入格式:
QRegExp regExp("^(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])[.](\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])[.](\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])[.](\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])$");
ui.IP_lineEdit->setValidator(new QRegExpValidator(regExp, this));