Question

I’m trying to connect a combo box value and a label such that when the combo box changes the label reflects that. I have googled my heart out trying to find an answer but, as of yet, nothing has worked; I still get the error:no matching function for call to mainWindow::connect(QComboBox*&, const char [38], QString*, const char [26])

I have tried QObject::connect, QWidget::connect and anything else dealing with Qt, but to no avail.

Creating a label that says the combo box value is not my final intention for the program. Rather, I wish to get it working with a simple label then change it to what I want it to display (thus the tempLabel).

mainwindow.h:

class MainWindow : public QMainWindow
{
public:
    MainWindow();

private slots:
    QString getClass(QComboBox *box);
};

mainwindow.cpp:

MainWindow::MainWindow()
{
    QString qMathClassName;

    QComboBox* mathClassCombo = new QComboBox;
    QLabel* label = new QLabel(qMathClassName);

    // omitting layout code...

    connect(mathClassCombo, SIGNAL(currentIndexChanged(const QString &)), 
            &qMathClassName, SLOT(getClass(mathClassCombo)));
}

QString MainWindow::getClass(QComboBox *box)
{
    return box->currentText();
}

Any help would be greatly appreciated!

Answer 1

You are connecting a signal to a slot with a different signature. You have to change your slot to something like

getClass(const QString &)

to match currentIndexChanged signal.