Question

I need to change the mainwindow or the native app size width x height in other class not in the mainwindow class. How can I do this?

void OptionsDialog::resetWindowLayoutClicked(QResizeEvent* event) {
    QMainWindow::resize(640, 483);
}

This is my first try but with no happiness.

Answer 1

I would make a signal and connect it to a slot in the main window.

For example:

class OptionsDialog : public QDialog
{
    Q_OBJECT
signals:
    void resize(int w, int h);
};

class MainWindow : public QMainWindow
{
    Q_OBJECT
private slots: 
    void resizeRequest(int w, int h);
};

void OptionsDialog::resetWindowLayoutClicked(QResizeEvent* event) 
{
    emit resize(640, 483);
}

When you create the OptionsDialog, connect the signal like this:

OptionsDialog* d = new OptionsDialog(this);
connect(d, SIGNAL(resize(int,int)), this, SLOT(resizeRequest(int,int)));

And implement the slot:

void MainWindow::resizeRequest(int w, int h)
{
    resize(w, h);
}