QMenu: How to customize the menu items of QMenu

I want to build a dropdown list control with QPushButton and QMenu like below:

QPushButton* menuBt = new QPushButton("Please select");
menuBt->setFlat(true);
QMenu* menu = new QMenu();
menuBt->setMenu(menu);
QWidgetAction* wa1 = new QWidgetAction(menu);
QLabel* l1 = new QLabel("Option1");
wa1->setDefaultWidget(l1);
menu->addAction(wa1);
QWidgetAction* wa2 = new QWidgetAction(menu);
QLabel* l2 = new QLabel("Option2");
wa2->setDefaultWidget(l2);
menu->addAction(wa2);
menu->setStyleSheet("QMenu::item {font-family: \"Arial\"; font-size: 13pt; color: #808080; border: 1px solid gray; background-color: rgb(234,234,234);}"
    "QMenu::item:hover {background-color: rgb(0, 0, 255);}");
menuBt->setStyleSheet("QPushButton {font-family: \"Arial\"; font-size: 13pt; color: #808080; border: 1px solid gray;padding: 1px 18px 1px 3px;min-width: 6em; background-color: rgb(234,234,234);}");

I set the font and hover background color to the menu items by setStyleSheet, but seems it doesn't work. How make the font and hover background color work on menu items?

Answer:

class QTDropDownButton : public QPushButton
{
    Q_OBJECT
public:
    QTDropDownButton(QString text, QWidget *parent = nullptr);

    void addItem(QString text);

    protected slots:
        void menuAboutToShow();

private:
    QMenu* menu_;
};

    QTDropDownButton::QTDropDownButton(QString text, QWidget *parent) :
    QPushButton(text, parent)
{
    setFlat(true);
    menu_ = new QMenu();
    setMenu(menu_);

    connect(menu_, SIGNAL(aboutToShow()), this, SLOT(menuAboutToShow()));

    setStyleSheet("font-family: Arial; font-size: 13pt; color: #808080; border: 1px solid gray; background-color: rgb(234,234,234);");
    menu_->setStyleSheet("QMenu::item {font-family: Arial; font-size: 13pt; color: #808080; border: 1px solid gray; background-color: rgb(234,234,234);}"
        "QMenu::item:selected {background-color: rgb(0, 255, 255);}"
        "QLabel {font-family: Arial; font-size: 13pt;}"
        "QLabel:hover {background-color: rgb(0, 0, 255);}");
}

void QTDropDownButton::addItem(QString text)
{
    if(!menu_)
        return;

    QWidgetAction* wa1 = new QWidgetAction(menu_);
    QLabel* l1 = new QLabel(text);
    wa1->setDefaultWidget(l1);
    menu_->addAction(wa1);
}

void QTDropDownButton::menuAboutToShow()
{
    if(menu_)
        menu_->setFixedWidth(this->width());
}

To set the font-family you don't need to put quotes around the Arial. I believe this prevents your style sheet from parsing correctly.

A side note: at the moment only your menuBt is styled, other buttons will look like default buttons. To change button style for all buttons in the menu, move the style into the setStylesheet() call of the menu like this:

menu->setStyleSheet("QMenu::item {font-family: Arial; font-size: 13pt; color: #808080; border: 1px solid gray; background-color: rgb(234,234,234);}" +
"QMenu::item:hover {background-color: rgb(0, 0, 255);}" +
"QPushButton {font-family: Arial; font-size: 13pt; color: #808080; border: 1px solid gray;padding: 1px 18px 1px 3px;min-width: 6em; background-color: rgb(234,234,234);}");

But if you want only this one button to look different, it is correct to call setStylesheet() on it, but you can omit the selector, like this:

menuBt->setStyleSheet("font-family: Arial; font-size: 13pt; color: #808080; border: 1px solid gray;padding: 1px 18px 1px 3px;min-width: 6em; background-color: rgb(234,234,234);");