Unsolved QMessagebox I would like to know how the three seconds shut down.

[ForestPoem]

QMessageBox* msgBox = new QMessageBox(QMessageBox::Information,
"This is the title",
"OK Button Result",
QMessageBox::Ok, this,
Qt::FramelessWindowHint);
msgBox->setInformativeText("-Wait ");
msgBox->exec();

my qmessagebox
how to After 3 seconds Shutdown

[kshegunov]

You can't, not with this code anyway. You could create a modeless dialog (QMessageBox is a QDialog subclass), meaning you call msgBox-show() instead of msgBox->exec() and start a single-shot timer for 3 seconds, that has its timeout() signal connected to the slot you want to use for shutdown (i.e. if shutdown means just hiding the message box, you either connect it to hide() or deleteLater(), depending on your particular needs). Bear in mind that while the modeless message box will not block the program, you might need to deal with the case of losing focus - the user clicking on your main window/widget etc.

[Devopia53]

You can use the following: use the modal dialog...

QMessageBox msgBox(QMessageBox::Information,
"This is the title",
"OK Button Result",
QMessageBox::Ok, this,
Qt::FramelessWindowHint);
msgBox.setInformativeText("-Wait ");

QTimer timer; // Don't use QTimer::singleShot()
timer.setSingleShot(true);
connect(&timer, &QTimer::timeout, [&]{ msgBox.close(); }); // with c++11
timer.start(3000);

msgBox.exec();

[ForestPoem]

@Devopia53

source code dump is error

error: 'void QTimer::timeout()' is protected

error: within this context

error: no matching function for call to 'class::connect(QTimer*, void (QTimer::)(), class::class(QWidget)::<lambda()>)'

[Devopia53]

@ForestPoem

If your compiler does not support C++11 lambda expressions, you can use following:

connect(&timer, &QTimer::timeout, &msgBox, &QMessageBox::close);