QT 设立左上角按钮

      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: