我在跟着做《C++ GUI Qt4 编程》书上39页的tools菜单下的Recalculate的时候，出来的程序按F9一直没效果，代码是这样的：
recalculateAction= new QAction(tr("&Recalculate"), this);
recalculateAction->setShortcut(Qt::Key_F9);
recalculateAction->setStatusTip(tr("Recalculate of the spreadsheet"));
connect(recalculateAction,SIGNAL(triggered()), spreadsheet, SLOT(recalculate()));
不知道为什么不灵，哪位大神帮忙看看，小弟感激不尽~
