random technical notes

class MainWindow : public QMainWindow
{
 Q_OBJECT;
public:
 MainWindow(QWidget *parent = 0) : QMainWindow(parent)
 {
   QSettings settings;
   restoreGeometry(settings.value("mainWindowGeometry").toByteArray());
   // create docs, toolbars, etc...
   restoreState(settings.value("mainWindowState").toByteArray());
 }

 void closeEvent(QCloseEvent *event)
 {
   QSettings settings;
   settings.setValue("mainWindowGeometry", saveGeometry());
   settings.setValue("mainWindowState", saveState());
 }
};

int main(int argc, char *argv[])
{
 QApplication a(argc, argv);
 QCoreApplication::setOrganizationDomain("OrgDomain");
 QCoreApplication::setOrganizationName("OrgName");
 QCoreApplication::setApplicationName("AppName");
 QCoreApplication::setApplicationVersion("1.0.0");

 MainWindow w;
 w.show();

 return a.exec();
}

The above code will save and restore window position, size, toolbar visibility, toolbar docking area, dock states, locations and sizes. It saves using QSettings which will store your settings in a platform correct way.

Source