Type conversion and networkAccessManager->networkAccessible() problems in QT6.6

agha

Hello friends, I have a type conversion problem in QT6.6. Although the function below works in older versions of QT, I get an error in QT6.6. The error is stated below.
the code:
void MainWindow::connectSerialPortComboBox() {

connect(ui->serialPortComboBox, static_cast<void (QComboBox::*)(const QString&)>(&QComboBox::currentIndexChanged),
        picDriver, &QtPicDriver::setSerialPort);
connect(ui->serialPortComboBox, static_cast<void (QComboBox::*)(const QString&)>(&QComboBox::currentIndexChanged),
        this, &MainWindow::saveSerialPortPref);

}
and Errors:
error: static_cast from 'void (QComboBox::)(int)' to 'void (QComboBox::)(const QString &)' is not allowed
error: static_cast from 'void (QComboBox::)(int)' to 'void (QComboBox::)(const QString &)' is not allowed

Also, how can I recode the networkAccessManager->networkAccessible() operation in QT6.6?
Thank you in advance for your help.

void GitHubUpdateChecker::performCheck()
{
QNetworkAccessManager *manager = new QNetworkAccessManager(this);

if(softFailures >= maxTries) {
	emit checkFailed();
	checkInProgress = false;
	return;
}

if(networkAccessManager->networkAccessible())
    networkAccessManager->get(QNetworkRequest(url));
else {
    emit checkFailed();
    checkInProgress = false;
    return;
}

}
the Error:

error: no member named 'networkAccessible' in 'QNetworkAccessManager'
error: no member named 'networkAccessible' in 'QNetworkAccessManager'

JonB

@agha said in Type conversion and networkAccessManager->networkAccessible() problems in QT6.6:

and Errors:
error: static_cast from 'void (QComboBox::)(int)' to 'void (QComboBox::)(const QString &)' is not allowed
error: static_cast from 'void (QComboBox::)(int)' to 'void (QComboBox::)(const QString &)' is not allowed

QComboBox::currentIndexChanged() (not currentTextChanged()) takes an int index as its parameter. I don't understand how you can try to cast that to a function which takes a const QString& instead, which is what the error message says, and I don't know how that got through in any version of Qt --- ah, see below.

I tried it in Qt5 and got:

warning: ‘void QComboBox::currentIndexChanged(const QString&)’ is deprecated: Use currentIndexChanged(int) instead, and get the text using itemText(index) [-Wdeprecated-declarations]

178 | connect(combo, static_cast<void (QComboBox::*)(const QString&)>(&QComboBox::currentIndexChanged),

So QComboBox::currentIndexChanged(const QString&) must have been finally removed in Qt6.

And btw, even at Qt5 your code was not a good way to specify the choice of overloaded method if there are multiple possibilities. For that and if you come across this again at Qt6, as per https://doc.qt.io/archives/qt-5.14/qcombobox.html#currentIndexChanged-1 use QOverload<>::of():

Note: Signal currentIndexChanged is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:

connect(comboBox, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
    [=](const QString &text){ /* ... */ });

agha

@JonB
Thank you for your answer. I'm a newbie to QT, so I need some more help.

JonB

@agha

error: no member named 'networkAccessible' in 'QNetworkAccessManager'

https://doc.qt.io/qt-6/network-changes-qt6.html#bearer-management-is-removed

QNetworkInformation::reachability(), introduced in Qt 6.1, replaces the QNetworkAccessManager::networkAccessible() function, while adding more detailed information about the reachability of the network. See its documentation for more details.