Qt如何编写程序启动界面

#include <QApplication>
#include <QSplashScreen>
#include <QDateTime>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QSplashScreen *splash = new QSplashScreen;

    splash->setPixmap(QPixmap(":/images/china.jpg"));
    //splash->setWindowFlags(Qt::WindowStaysOnTopHint);
    splash->show();

    splash->showMessage("Will start in 1 seconds",Qt::AlignTop,Qt::blue);

    QDateTime n=QDateTime::currentDateTime();
        QDateTime now;
        do{
            now=QDateTime::currentDateTime();
            a.processEvents();
        } while (n.secsTo(now)<=2);


    splash->showMessage("Started...",Qt::AlignTop,Qt::blue);

    do{
        now=QDateTime::currentDateTime();
        a.processEvents();
    } while (n.secsTo(now)<=2);

    MainWindow w;
    w.show();
    splash->finish(&w);
    delete splash;

    return a.exec();
}