如何使用委托在QHeaderView部分绘制像素图？

Question

问题：我需要将小像素图绘制到QHeaderView部分，如此图所示（位于该部分右角的像素图，标有红色方块）：

据我了解，有两种方法可以做到：

1. 重新实现QHeaderView的{​​{1}}方法。

2. 从paintSection()班级创建代理并重新实施QStyledItemDelegate方法。

如果我尝试使用下面的代码（1）变体， filter pixmap 根本不显示：

paint()

（2）变体是这样的：

void DecorativeHeaderView::paintSection( QPainter* painter, const QRect& rect, int logicalIndex ) const
{
     if( !rect.isValid() )
     {
          return;
     }

     // get the state of the section
     QStyleOptionHeader option;
     initStyleOption( &option );

     // setup the style options structure
     option.rect = rect;
     option.section = logicalIndex;
     option.iconAlignment = Qt::AlignVCenter | Qt::AlignHCenter;

     QVariant variant = model()->headerData( logicalIndex, orientation(), Qt::DecorationRole );
     option.icon = qvariant_cast< QIcon >( variant );
     if( option.icon.isNull() )
     {
          option.icon = qvariant_cast< QPixmap >( variant );
     }

     // draw the section
     if( !option.icon.isNull() )
     {
          style()->drawControl( QStyle::CE_Header, &option, painter, this );
     }
     else
     {
          QHeaderView::paintSection( painter, rect, logicalIndex );

// HERE is where I'm trying to draw my filter picture!!!

          if( logicalIndex == filteredLogicalIndex_ )
          {
               QPixmap pixmap( ":/spreadsheet/images/spreadsheet/filter_icon_table.png" );
               int x = rect.right() - pixmap.width();
               int y = rect.top() + ( rect.height() - pixmap.height() ) / 2;

               painter->drawPixmap( QPoint( x, y ), pixmap );
          }
     }
}

已创建委托，但函数未启动class HeaderDelegate : public QStyledItemDelegate { Q_OBJECT Q_DISABLE_COPY( HeaderDelegate ) public: HeaderDelegate( QObject* parent = 0 ) : QStyledItemDelegate( parent ) {} virtual ~HeaderDelegate() {} virtual void paint( QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index ) const; }; // HeaderDelegate void HeaderDelegate::paint( QPainter* painter, const QStyleOptionViewItem& option, const QModelIndex& index ) const { // THIS method never starts!!! if( index.column() == 2 ) { QPixmap pixmap( ":/spreadsheet/images/spreadsheet/filter_icon_table.png" ); int x = option.rect.right() - pixmap.width(); int y = option.rect.top() + ( option.rect.height() - pixmap.height() ) / 2; painter->save(); painter->drawPixmap( QPoint( x, y ), pixmap ); painter->restore(); } QStyledItemDelegate::paint( painter, option, index ); } DecorativeHeaderView::DecorativeHeaderView( Qt::Orientation orientation, QWidget* parent /* = 0 */ ) : QHeaderView( orientation, parent ) , filteredLogicalIndex_( -1 ) { setItemDelegate( new HeaderDelegate( this ) ); } 方法！

有任何帮助吗？

谢谢！

Answer 1

现在似乎不可能。

来自Qt文档：

注意：每个标头都会为每个部分本身呈现数据，而不依赖于委托。因此，调用标头的setItemDelegate（）函数将无效。

How to have dynamic pixmap in a QHeaderView item

但是你可以覆盖QHeaderView :: paintSection方法。 subclassing-QHeaderView

class HeaderView : public QHeaderView {
    Q_OBJECT

public:
    HeaderView(Qt::Orientation orientation, QWidget * parent = 0)
        : QHeaderView(orientation, parent), p("333222.jpeg") {
    }

    int sectionSizeHint ( int /*logicalIndex*/ ) const { return p.width(); }

protected:
    void paintSection(QPainter * painter, const QRect & rect, int /*logicalIndex*/) const {
        painter->drawPixmap(rect, p);
    }

private:
    QPixmap p;
};