How to require a password to close a window? - c++

Question

I would like to protect a window from closing, so when the user attempts to do that, a password has to be entered in order to complete the action. There is no need for a username to be entered.
I know how to intercept the QWidget::closeEvent, as in this example:
void MainWindow::closeEvent(QCloseEvent *event) {
QMessageBox msgBox;
msgBox.setText(tr("Do you want to close the window?"));
msgBox.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
msgBox.setDefaultButton(QMessageBox::No);
msgBox.setModal(true);
int ret = msgBox.exec();
if (ret == QMessageBox::Yes)
event->accept();
else
event->ignore();
}
The problem is, that the example uses QMessageBox, which does not allow a text to be entered, hence it does not suit my needs.
How to modify the code in order to prompt for a password?

Answer 1

Solution
Instead of QMessageBox use QDialog and shape it to your needs.
Example
Here is an example I have prepared for you in order to demonstrate how the proposed solution could be implemented:
void MainWindow::closeEvent(QCloseEvent *event) {
QDialog dialog(this);
auto *layoutDialog = new QVBoxLayout(&dialog);
auto *lineEdit = new QLineEdit(&dialog);
auto *label = new QLabel(tr("Enter password to close the window:"), &dialog);
lineEdit->setEchoMode(QLineEdit::Password);
layoutDialog->addWidget(label);
layoutDialog->addWidget(lineEdit);
layoutDialog->addStretch();
connect(lineEdit, &QLineEdit::editingFinished, [&]() {
dialog.done(lineEdit->text() == "11223344");
});
dialog.resize(250, 100);
if (dialog.exec())
event->accept();
else
event->ignore();
}
Note: Of course you have to come up with a smarter way of how to keep the password safe.