Custom List Implementation

For advanced dropdown lists containing images, text, and interactive elements (similar to QQ login interface), we need to extend QComboBox functionality:

class CustomItemWidget : public QWidget {
    Q_OBJECT
signals:
    void itemClicked();
    void textChanged(const QString &);

public:
    CustomItemWidget(const QString &text, QWidget *parent = nullptr);
    void updateText(const QString &text);
    void setIcons(const QString &normal, const QString &hover);
    void setHoverState(bool active);

protected:
    bool eventFilter(QObject *, QEvent *) override;
    void mousePressEvent(QMouseEvent *) override;
    void mouseReleaseEvent(QMouseEvent *) override;

private:
    void initUI();
    bool m_pressed = false;
    QWidget *m_container = nullptr;
    QPushButton *m_iconBtn = nullptr;
    QLabel *m_textLabel = nullptr;
};

The implementation involves:

1. Creating a custom widget with hover effects and click handling
2. Managing event filtering for proper hover behavior
3. Integrating with QComboBox through QListWidget

void setupCustomList() {
    QListWidget *list = new QListWidget;
    list->setViewMode(QListView::ListMode);

    for (int i = 0; i < 5; i++) {
        CustomItemWidget *item = new CustomItemWidget("Item " + QString::number(i));
        connect(item, &CustomItemWidget::textChanged, [this, list](const QString &text) {
            m_comboBox->hidePopup();
            if (m_comboBox->isEditable()) {
                m_comboBox->setCurrentText(text);
            } else {
                for (int j = 0; j < list->count(); ++j) {
                    if (list->itemWidget(list->item(j)) == sender()) {
                        m_comboBox->setCurrentIndex(j);
                    }
                }
            }
        });
        item->setIcons(":/icons/normal.png", ":/icons/hover.png");
        item->setFixedSize(150, 45);
        
        QListWidgetItem *listItem = new QListWidgetItem(list);
        list->setItemWidget(listItem, item);
        item->installEventFilter(this);
    }

    m_comboBox->setModel(list->model());
    m_comboBox->setView(list);
    m_comboBox->setEditable(true);
    m_comboBox->setMaxVisibleItems(3);
}

Custom Table Implementation

For dropdown tables with multiple selectable items, we extend QCheckBox:

class CustomCheckBox : public QCheckBox {
public:
    CustomCheckBox(QWidget *parent = nullptr) : QCheckBox(parent) {}
protected:
    bool hitButton(const QPoint &) const override { return true; }
};

The table implementation:

void setupCustomTable() {
    QTableWidget *table = new QTableWidget(3, 3);
    table->verticalHeader()->hide();
    table->horizontalHeader()->hide();
    table->setShowGrid(false);
    
    for (int row = 0; row < 3; ++row) {
        table->setRowHeight(row, 50);
        for (int col = 0; col < 3; ++col) {
            CustomCheckBox *cb = new CustomCheckBox;
            cb->setFixedSize(50, 50);
            cb->setText("Option " + QString::number(row*3 + col));
            cb->setStyleSheet("QCheckBox {background:lightgray;}"
                             "QCheckBox:checked {background:white;}");
            
            connect(cb, &QCheckBox::clicked, [this]() {
                // Handle multiple selection logic
            });
            
            table->setCellWidget(row, col, cb);
            cb->installEventFilter(this);
        }
    }

    m_comboBox->setModel(table->model());
    m_comboBox->setView(table);
}

Key considerations include proper sizing to avoid scrollbars and handling multiple selections in the dropdown table.