在接触Qt这段时间以来，经常遇到菜单项的问题（右键菜单、托盘菜单、按钮菜单等），QMenu用于菜单栏,上下文菜单,弹出菜单等，利用QMenu+QAction就可以达到效果！

    右键菜单实现：通过重写contextMenuEvent(QContextMenuEvent *event)事件，QMenu+QAction即可完美实现！

    对象：QTreeWidget

    实现方式：createActions用于创建菜单、菜单项，contextMenuEvent用于实现菜单的显示，translateLanguage用于实现菜单的文本（此方法主要设置多语化使用）

void ImageTree::createActions()

{

    //创建菜单、菜单项

    pop_menu = new QMenu();

    add_images_action = new QAction(this); 

    add_folder_action = new QAction(this);

    remove_selected_action = new QAction(this);

    remove_all_action = new QAction(this);

    //连接信号与槽

    connect(add_images_action, &QAction::triggered, this, &ImageTree::selectImages);

    connect(add_folder_action, &QAction::triggered, this, &ImageTree::selectFolder);

    connect(remove_selected_action, &QAction::triggered, this, &ImageTree::removeSelectedImages);

    connect(remove_all_action, &QAction::triggered, this, &ImageTree::removeAllImages);

}

void ImageTree::contextMenuEvent(QContextMenuEvent *event)

{

    //清除原有菜单

    pop_menu->clear();

    pop_menu->addAction(add_images_action);

    pop_menu->addAction(add_folder_action);

    pop_menu->addAction(remove_selected_action);

    pop_menu->addAction(remove_all_action);

    //菜单出现的位置为当前鼠标的位置

    pop_menu->exec(QCursor::pos());

    event->accept();

}

void ImageTree::translateLanguage()

{

    add_images_action->setText(tr("add images"));

    add_folder_action->setText(tr("add folder"));

    remove_selected_action->setText(tr("remove selected images"));

    remove_all_action->setText(tr("remove all images"));

}

效果如下：

    二级菜单的实现（包括三级菜单或者更多）也类似，只需要使用QMenu的addMenu()方法即可！关于右键二级菜单的东西之前介绍过，详情请参阅：QTableWidget详解（样式、右键菜单、表头塌陷、多选等）。