1.建立繼承QStyledItemDelegate的類。

ScreenTreeWidgetItemDelegate::ScreenTreeWidgetItemDelegate(ScreenTreeWidget *parent):
    QStyledItemDelegate(parent),
    m_handler(parent)
{


}

2. 在建立的 類中實現paint函式，所有單元格的畫的內容都在paint函式裡來畫

void ScreenTreeWidgetItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if(!index.data(Qt::UserRole).toBool())
        return;

    QRect rect = option.rect;
    rect.setHeight(rect.height()-1);
    painter->fillRect(rect, QColor(39,44,60));

    painter->setPen(Qt::white);
    QTextOption op;
    op.setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);


    painter->drawText(option.rect, index.data(Qt::DisplayRole).toString(), op);

    QRect iconRect(10,option.rect.y()+(option.rect.height()-16)/2,16,16);
    if(m_handler->isExpanded(index))
    {
        if(option.state & QStyle::State_MouseOver)
        {
            QImage img(":/image/open_hover");
            painter->drawImage(iconRect, img, img.rect());
        }
        else
        {
            QImage img(":/image/open");
            painter->drawImage(iconRect, img, img.rect());
        }

    }
    else
    {
        if(option.state & QStyle::State_MouseOver)
        {
            QImage img(":/image/close_hover");
            painter->drawImage(iconRect, img, img.rect());
        }
        else
        {
            QImage img(":/image/close");
            painter->drawImage(iconRect, img, img.rect());
        }

    }

}
 

3.使用，在使用類中設定

setItemDelegate(new ScreenTreeWidgetItemDelegate(this));