给QWidget添加菜单栏

来源：互联网发布：大学室友不好知乎编辑：程序博客网时间：2024/05/28 15:40

与QToolBar类似，QMenuBar可以直接添加一个QAction，用户点击就会触发QAction::trigger信号，调用与之关联的槽。

此外，还可以先把一个QAction添加到QMenu里面，再把QMenu添加给QMenuBar。点击QMenu之后，它含有的所有QAction都会下拉出来，供用户选择。QMenu甚至还可以级联。

与QToolBar一样，QMenuBar占据的区域也在被paintEvent绘制的范围内。如果程序员想要在窗体上画图，应避免菜单栏把图像遮住。

#ifndef MAINWINDOW_H#define MAINWINDOW_H#include <QMainWindow>#include <QMenu>#include <QMenuBar>#include <QAction>#include <QResizeEvent>#include <QPaintEvent>class MainWindow : public QMainWindow{    Q_OBJECTpublic:    MainWindow(QWidget *parent = 0);    ~MainWindow();    QMenuBar            *           m_pMenuBar;    QAction             *           m_arrAct[3];    QMenu               *           m_pMenu;public slots:    void                            OnClick1(void);    void                            OnClick2(void);    void                            OnClick3(void);protected:    void                resizeEvent(QResizeEvent *);    void                paintEvent(QPaintEvent *);};#endif // MAINWINDOW_H

#include "mainwindow.h"

#include <QDebug>

#include <QPainter>

#include <QImage>

MainWindow::MainWindow(QWidget *parent)

    : QMainWindow(parent)

    m_pMenuBar = new QMenuBar(this);

    m_arrAct[0] = new QAction(QString::fromLocal8Bit("123"), this);

m_arrAct[1] = new QAction(QString::fromLocal8Bit("abc"), this);

    m_arrAct[2] = new QAction("qwe", this);

    m_pMenu = new QMenu("789");

    m_pMenuBar->addAction(m_arrAct[0]);

    m_pMenuBar->addAction(m_arrAct[1]);

    m_pMenuBar->addMenu(m_pMenu);

    m_pMenu->addAction(m_arrAct[2]);

    QObject::connect(m_arrAct[0], SIGNAL(triggered()),

            this, SLOT(OnClick1()));

    QObject::connect(m_arrAct[1], SIGNAL(triggered()),

            this, SLOT(OnClick2()));

    QObject::connect(m_arrAct[2], SIGNAL(triggered()),

            this, SLOT(OnClick3()));

MainWindow::~MainWindow()

    delete m_pMenuBar;

    delete m_pMenu;

    delete m_arrAct[0];

    delete m_arrAct[1];

    delete m_arrAct[2];

void MainWindow::resizeEvent(QResizeEvent *e)

    m_pMenuBar->setGeometry(0,0,width(), 50);

void MainWindow::paintEvent(QPaintEvent *e)

    QImage img(QString("E:\\lena.jpg"));

    QPainter qp;

    qp.begin(this);

    qp.drawImage(QRect(0, m_pMenuBar->height(), width(), height() - m_pMenuBar->height()),

                 img, QRect(img.rect()));

    qp.end();

void MainWindow::OnClick1(void)

    qDebug()<<1;

void MainWindow::OnClick2(void)

    qDebug()<<2;

void MainWindow::OnClick3(void)

    qDebug()<<3;

效果：

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