QT detection card reader analog keyboard input

bool GiveBackCard2::eventFilter(QObject *obj, QEvent *ev)
{
if (ev->type() == QEvent::KeyPress)
{
QKeyEvent event = static_cast<QKeyEvent>(ev);
int iKey = event->key();
if(iKey == Qt::Key_Return || iKey == Qt::Key_Enter) // Enter to send the stored information
{
if(!_outerCardID.isEmpty())
{
if(_outerCardID==_cardID)
{
_canGiveBack=true;
setTipLabel(QString::fromLocal8Bit(“ The match is successful ”));
}
else
{
_canGiveBack=false;
setTipLabel(QString::fromLocal8Bit(“ Matching failure ”));
}
}
return true;
}
else if(0 <= iKey && 128 > iKey) // Character key values can be displayed
{
// Judge the time interval from the last valid key , Greater than 200ms Reset input storage , Otherwise, accumulate the recorded characters
int iElapsed = m_tmWatch.msecsTo(QTime::currentTime());
//qDebug() << iElapsed << iKey;
if(200 < iElapsed)
{
_outerCardID = event->text();
}
else
{
_outerCardID += event->text();
}
m_tmWatch = QTime::currentTime();
}
}
return false;
}
When with Qt::Tool when , The window has no focus by default , Need to use code to control activation .
this->setWindowFlags(Qt::FramelessWindowHint|Qt::Tool);
Be careful , Card reader input requires manual activation of the window interface ：
int GiveBackCard2::exec()
{
show();
activateWindow();
return QDialog::exec();
}