QT 菜单程序

MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include<QMainWindow>
#include<QMessageBox>

class MainWindow : public QMainWindow{
    Q_OBJECT
public:
    MainWindow();

private slots:
    void fExit();
    void iInfo();

private:
    void createMenus();
    void createActions();

    QAction *exit;
    QAction *info;
    QMenu *file;
    QMenu *about;
    QMessageBox *msgBox;
};

#endif // MAINWINDOW_H

MainWindow.cpp

#include<QtGui>
#include"MainWindow.h"

MainWindow::MainWindow(){
    QWidget *widget=new QWidget;
    setCentralWidget(widget);

    QWidget *topfiller=new QWidget;
    topfiller->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);

    QWidget *bottomFiller=new QWidget;
    bottomFiller->setSizePolicy(QSizePolicy::Expanding,QSizePolicy::Expanding);

    createActions();
    createMenus();

    QVBoxLayout *layout=new QVBoxLayout;
    layout->addWidget(topfiller);
    layout->addWidget(bottomFiller);
    widget->setLayout(layout);

    setWindowTitle(tr("Main Window"));
    resize(512,480);

}

void MainWindow::createActions(){
    exit=new QAction(tr("Exit"),this);
    exit->setShortcut(QKeySequence::Close);
    connect(exit,SIGNAL(triggered()),this,SLOT(fExit()));

    info =new QAction(tr("Info"),this);
    info->setShortcut(QKeySequence::HelpContents);
    connect(info,SIGNAL(triggered()),this,SLOT(iInfo()));

}

void MainWindow::createMenus(){
    file=menuBar()->addMenu(tr("File"));
    file->addAction(exit);

    about=menuBar()->addMenu(tr("About"));
    about->addAction(info);
}

void MainWindow::fExit(){
    MainWindow::close();
}

void MainWindow::iInfo(){
    msgBox=new QMessageBox;
    msgBox->setText(tr("hello world"));
    msgBox->setIcon(QMessageBox::Question);
    msgBox->setStandardButtons(QMessageBox::Ok);
    msgBox->exec();
}

Main.cpp

#include<QApplication>
#include"MainWindow.h"

int main(int argc,char* argv[]){
    QApplication app(argc,argv);
    MainWindow wnd;
    wnd.show();
    app.exec();

}

运行效果：