Question

I have a Qt application which needs to be loaded on mobile devices of different screen sizes. How do I make it autofit to the mobile device’s screen size?

Answer 1

If you want your application’s main window to occupy the whole screen as soon as it starts, use QWidget::showMaximized, e.g.

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    MyMainWidget widget;
    widget.showMaximized();
    return app.exec();
}

Note that showMaximized is a convenience function which internally calls the QWidget::setWindowState mentioned by Andrew:

void QWidget::showMaximized()
{
    // ...
    setWindowState((windowState() & ~(Qt::WindowMinimized | Qt::WindowFullScreen))
                   | Qt::WindowMaximized);
    show();
}