qt事件过滤器妙用

TestMenu派生自QMenu，popUp显示出来后，期望点击程序其它位置时，主动关闭该界面。通过事件过滤器，可以很方便的实现。
具体代码如下：

bool EventFilter::eventFilter(QObject *watched, QEvent *event)  {
    if (event->type() == QEvent::MouseButtonPress) {
        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
        QPoint globalPos = mouseEvent->globalPos();
        QPoint localPos = menu->mapFromGlobal(globalPos);
        if (menu && menu->isVisible()) {
            if(!menu->rect().contains(localPos))
                menu->close();
        }
    }
    return QObject::eventFilter(watched, event);
}
TestMenu::TestMenu(QWidget *parent):QMenu(parent){
    setAttribute(Qt::WA_TranslucentBackground);
     setWindowFlags(Qt::FramelessWindowHint | Qt::Tool);
    this->setStyleSheet(menuBgQSS);

    filter = new EventFilter(this);
    qApp->installEventFilter(filter);
}

TestMenu::~TestMenu(){
    qApp->removeEventFilter(filter);
}