为什么点击QAction 3 没有对话框弹出？
#ifndef UI_SS_H
#define UI_SS_H
#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QMainWindow>
#include <QtGui/QMenu>
#include <QtGui/QMenuBar>
#include <QtGui/QStatusBar>
#include <QtGui/QWidget>
#include <QMessageBox>
QT_BEGIN_NAMESPACE
class Ui_MainWindow
{
public:
QAction *action;
QAction *action_2;
QAction *action_3;
QWidget *centralwidget;
QMenuBar *menubar;
QMenu *menu;
QMenu *menu_2;
QStatusBar *statusbar;
void setupUi(QMainWindow *MainWindow)
{
if (MainWindow->objectName().isEmpty())
MainWindow->setObjectName(QString::fromUtf8("MainWindow"));
MainWindow->resize(800, 600);
action = new QAction(MainWindow);
action->setObjectName(QString::fromUtf8("action"));
action_2 = new QAction(MainWindow);
action_2->setObjectName(QString::fromUtf8("action_2"));
action_3 = new QAction(MainWindow);
action_3->setObjectName(QString::fromUtf8("action_3"));
centralwidget = new QWidget(MainWindow);
centralwidget->setObjectName(QString::fromUtf8("centralwidget"));
MainWindow->setCentralWidget(centralwidget);
menubar = new QMenuBar(MainWindow);
menubar->setObjectName(QString::fromUtf8("menubar"));
menubar->setGeometry(QRect(0, 0, 800, 20));
menu = new QMenu(menubar);
menu->setObjectName(QString::fromUtf8("menu"));
menu_2 = new QMenu(menubar);
menu_2->setObjectName(QString::fromUtf8("menu_2"));
MainWindow->setMenuBar(menubar);
statusbar = new QStatusBar(MainWindow);
statusbar->setObjectName(QString::fromUtf8("statusbar"));
MainWindow->setStatusBar(statusbar);
menubar->addAction(menu->menuAction());
menubar->addAction(menu_2->menuAction());
menu->addAction(action);
menu->addAction(action_2);
menu->addAction(action_3);
retranslateUi(MainWindow);
QObject::connect(menubar, SIGNAL(hovered(QAction*)), MainWindow, SLOT(slot1()));
QObject::connect(menubar, SIGNAL(triggered(QAction*)), MainWindow, SLOT(slot2()));
QObject::connect(action_3, SIGNAL(activated ()), MainWindow, SLOT(slot1()));
QMetaObject::connectSlotsByName(MainWindow);
} // setupUi
void retranslateUi(QMainWindow *MainWindow)
{
MainWindow->setWindowTitle(QApplication::translate("MainWindow", "MainWindow", 0, QApplication::UnicodeUTF8));
action->setText(QApplication::translate("MainWindow", "\350\275\257\344\272\244\346\215\242\346\234\272\350\247\204\345\210\222", 0,
QApplication::UnicodeUTF8));
action_2->setText(QApplication::translate("MainWindow", "\345\252\222\344\275\223\347\275\221\345\205\263\350\247\204\345\210\222", 0,
QApplication::UnicodeUTF8));
action_3->setText(QApplication::translate("MainWindow", "\344\277\241\344\273\244\347\275\221\345\205\263\350\247\204\345\210\222", 0,
QApplication::UnicodeUTF8));
menu->setTitle(QApplication::translate("MainWindow", "\347\275\221\345\205\203\350\247\204\345\210\222", 0, QApplication::UnicodeUTF8));
menu_2->setTitle(QApplication::translate("MainWindow", "\345\270\246\345\256\275\350\247\204\345\210\222", 0, QApplication::UnicodeUTF8));
} // retranslateUi
void slot1(){QMessageBox msgBox; msgBox.setText("The document has been modified.");
msgBox.exec();;}
};
namespace Ui {
class MainWindow: public Ui_MainWindow {};
} // namespace Ui
QT_END_NAMESPACE
#endif // UI_SS_H
