QT 表格设置左上角按钮

      QT表格模型没有提供访问左上角按钮的API, 查看qtableview.cpp 发现其中有一个QTableCornerButton的私有类, 既然AP没有暴露出该类, 那我们如何设置左上角按钮的显示方式呢?

 

一. 设置左上角按钮背景色

      既然知道左上角按钮就是QTableCornerButton, 我们就可以通过该类名设置该按钮样式 

 table->setStyleSheet("QTableCornerButton::section{background-color:red;}");

 

二. 设置按钮文本

    虽然没有提供直接的访问方式,可以通过findChild()来定位到该按钮,然后设置其文本及显示宽度.

class TableWidget:public QTableWidget
{
public:
    TableWidget(int rows, int cols, QWidget* parent = 0)
        : QTableWidget(rows, cols, parent)
    {
        QAbstractButton* btn = findChild<QAbstractButton*>();
        if (btn)
        {
            btn->setText("Text");
            btn->installEventFilter(this);

            // adjust the width of the vertical header to match the preferred corner button width

            // (unfortunately QAbstractButton doesn't implement any size hinting functionality)

            QStyleOptionHeader opt;
            opt.text = btn->text();
            QSize s = (btn->style()->sizeFromContents(QStyle::CT_HeaderSection, &opt, QSize(), btn).
                       expandedTo(QApplication::globalStrut()));
            if (s.isValid())
                verticalHeader()->setMinimumWidth(s.width());
        }
    }

    bool eventFilter(QObject* o, QEvent* e)
    {
        if (e->type() == QEvent::Paint)
        {
            QAbstractButton* btn = qobject_cast<QAbstractButton*>(o);
            if (btn)
            {
                // paint by hand (borrowed from QTableCornerButton)

                QStyleOptionHeader opt;
                opt.init(btn);
                QStyle::State state = QStyle::State_None;
                if (btn->isEnabled())
                    state |= QStyle::State_Enabled;
                if (btn->isActiveWindow())
                    state |= QStyle::State_Active;
                if (btn->isDown())
                    state |= QStyle::State_Sunken;
                opt.state = state;
                opt.rect = btn->rect();
                opt.text = btn->text(); // this line is the only difference to QTableCornerButton

                opt.position = QStyleOptionHeader::OnlyOneSection;
                QStylePainter painter(btn);
                painter.drawControl(QStyle::CE_Header, opt);
                return true; // eat event

            }
        }
        return false;
    }
};

  

    运行效果: