有时我们希望在窗口中右键弹出菜单，这里来介绍一下QT中怎么实现.
.h 中添加事件相应函数声明和变量定义：

private:
    // 菜单事件
    void contextMenuEvent(QContextMenuEvent* event) override;

    void initMenu();

private:
    QMenu* m_pMenu = nullptr;

在构造函数中设置菜单选项

// 设置菜单策略
    this->setContextMenuPolicy(Qt::DefaultContextMenu);

this可以改为其它组件指针，这样就可以在指定组件内右键才弹出菜单。这里指在整个窗口右键都会弹出菜单。

菜单内容的初始化实现：

void Widget::initMenu()
{
    m_pMenu = new QMenu(this);
    QAction *pAc1 = new QAction("ac1");
    QAction *pAc2 = new QAction("ac2");
    QAction *pAc3 = new QAction("ac3");
    QAction *pAc4 = new QAction("ac4");
    QAction *pAc5 = new QAction("ac5");

    m_pMenu->addAction(pAc1);
    m_pMenu->addAction(pAc2);
    m_pMenu->addAction(pAc3);
    m_pMenu->addAction(pAc4);
    m_pMenu->addAction(pAc5);

    connect(pAc1, &QAction::triggered, [=]{
        QMessageBox::information(this, "title", "ac1");
    });

    connect(pAc2, &QAction::triggered, [=]{
        QMessageBox::information(this, "title", "ac2");
    });

    connect(pAc3, &QAction::triggered, [=]{
        QMessageBox::information(this, "title", "ac3");
    });

    connect(pAc4, &QAction::triggered, [=]{
        QMessageBox::information(this, "title", "ac4");
    });

    connect(pAc5, &QAction::triggered, [=]{
        QMessageBox::information(this, "title", "ac5");
    });
}

菜单的响应函数：

void Widget::contextMenuEvent(QContextMenuEvent* event)
{
    m_pMenu->exec(QCursor::pos());
}

实现如下图：

源代码实现：