QT无窗口状态下对键盘事件的监听

int main(int argc, char *argv[])
{
     QApplication a(argc, argv);
     Test *p = new Test;    
     a.installEventFilter(p);
     return a.exec();
}



bool Test::eventFilter(QObject *obj, QEvent *event)
{
    if(event->type() == QEvent::KeyPress)
    {
        static int index = 0;
        QKeyEvent *key=static_cast<QKeyEvent *>(event);
        .........
    }
    return QObject::eventFilter(obj,event);
}