QComboBox结合QCheckBox实现下拉列表复选框功能

QCheckboxCombo.h

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#include <QComboBox>
#include <QListView>

class QCheckboxCombo : public QComboBox
{
Q_OBJECT
public:
explicit QCheckboxCombo(QWidget *parent = nullptr);
bool eventFilter(QObject * watched, QEvent * event) override;
void hidePopup() override;
void showPopup() override;
void setDelimiter(QString str){ _delimiter = str; }

private:
QString _delimiter = ",";

signals:
void beforeOpen();
};

QCheckboxCombo.cpp

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#include "qcheckboxcombo.h"
#include <QMouseEvent>
#include <QDebug>

QCheckboxCombo::QCheckboxCombo(QWidget *parent) :
QComboBox(parent)
{
view()->viewport()->installEventFilter(this);
setEditable(true);
}

bool QCheckboxCombo::eventFilter(QObject * watched, QEvent * event)
{
if (event->type() == QEvent::MouseButtonRelease)
{
QModelIndex ind = view()->indexAt(((QMouseEvent*)event)->pos());
bool checked = view()->model()->data(ind, Qt::CheckStateRole).toBool();
view()->model()->setData(ind, !checked, Qt::CheckStateRole);
return true;
}
return QObject::eventFilter(watched, event);
}

void QCheckboxCombo::hidePopup()
{
QStringList values;
for (int i=0; i < count(); i++){
if (itemData(i, Qt::CheckStateRole).toBool()){
values << itemText(i);
}
}
setCurrentText(values.join(_delimiter));

QComboBox::hidePopup();
}

void QCheckboxCombo::showPopup()
{
QStringList values = currentText().split(_delimiter);

emit beforeOpen();

for (int i=0; i<count(); i++){
setItemData(i, values.contains(itemText(i)), Qt::CheckStateRole);
}
QComboBox::showPopup();
}

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QCheckboxCombo *combo = new QCheckboxCombo;
combo->setFixedSize(200, 30);
combo->addItem(tr("Once"));
combo->setItemIcon(0, QIcon("C:\\Users\\wangjun\\Downloads\\test.png"));
combo->addItem(tr("Twice"));
combo->setItemIcon(1, QIcon("C:\\Users\\wangjun\\Downloads\\test.png"));
combo->addItem(tr("Thrice"));
combo->setItemIcon(2, QIcon("C:\\Users\\wangjun\\Downloads\\test.png"));
ui->frame->layout()->addWidget(combo);
new QHBoxLayout(ui->frame);