External/common/combox/customcombobox.cpp

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

CustomComboBox::CustomComboBox(QWidget *parent)
    : QComboBox(parent)
{
    
}
CustomComboBox::~CustomComboBox()
{
}

/* 设置下拉框阴影 */
void CustomComboBox::setViewShadowEffect()
{
    /* 设置这个在Linux下，下拉框才会背景透明 */
    setStyle(QStyleFactory::create("Windows"));
    setView(new QListView());
    if (nullptr != view() && nullptr != view()->window()) 
    {
        view()->window()->setWindowFlags(Qt::Popup | Qt::FramelessWindowHint | Qt::NoDropShadowWindowHint);
        view()->window()->setAttribute(Qt::WA_TranslucentBackground);

        QGraphicsDropShadowEffect *pShadowEffect = new QGraphicsDropShadowEffect(this);
        pShadowEffect->setBlurRadius(LISTVIEW_MARGIN);  // 模糊度
        pShadowEffect->setColor(QColor(0, 0, 0, 90));   // 阴影的颜色
        pShadowEffect->setOffset(0, 0);                 // 水平和垂直偏移量
        view()->setGraphicsEffect(pShadowEffect);

        QApplication::setEffectEnabled(Qt::UI_AnimateCombo, false);
    }
}

void CustomComboBox::showPopup()
{
    QComboBox::showPopup();

    if (nullptr != view()) {
        view()->setMinimumWidth(width() + LISTVIEW_MARGIN * 2);
    }
    QWidget *popup = findChild<QFrame*>();
    if (nullptr != popup) {
        popup->move(mapToGlobal(QPoint(-LISTVIEW_MARGIN, height() - LISTVIEW_MARGIN + 4)));
    }
}