ts/demo/LHCoaxialSwitchSetInfo/comboBox/customcombobox.cpp

#include "customcombobox.h"
#include <QGraphicsDropShadowEffect>
#include <QAbstractItemView>
#include <QListView>
#include <QTimer>
#include <QDebug>
#include <QStyleFactory>

CustomComboBox::CustomComboBox(QWidget *parent)
    : QComboBox(parent)
    , m_nMargin(0)
{
    setStyle(QStyleFactory::create("Windows"));

    setView(new QListView());
    view()->window()->setWindowFlags(Qt::Popup|Qt::FramelessWindowHint|Qt::NoDropShadowWindowHint);
    view()->window()->setAttribute(Qt::WA_TranslucentBackground);

    QGraphicsDropShadowEffect *pShadowEffect = new QGraphicsDropShadowEffect(this);
    pShadowEffect->setBlurRadius(10); // 模糊度
    pShadowEffect->setColor(QColor(0, 0, 0, 76)); // 阴影的颜色
    pShadowEffect->setOffset(0, 0); // 水平和垂直偏移量
    view()->setGraphicsEffect(pShadowEffect);

    QTimer::singleShot(0, this, [=]
    {
        view()->setMinimumWidth(width()+m_nMargin*2);
    });
}
CustomComboBox::~CustomComboBox()
{
    qDebug()<<__func__;
}

void CustomComboBox::showPopup()
{
    QComboBox::showPopup();
    QWidget *popup = findChild<QFrame*>();
    popup->move(mapToGlobal(QPoint(-m_nMargin, height())));
}