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QCombobox 设置项目委托不为当前项目绘制..

我正在尝试创建一个组合框,显示不同的线类型(实线、虚线、虚线等)。目前我正在为其内容设置项目委托,以便绘制/绘制线型而不是显示名称。所有线型都在正确绘制,但是一旦我从组合框中选择任何线型,组合框的当前索引仅显示线名而不是绘制它。如何让它在当前组合框索引上绘制选定的线型?

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4 回答 4

3

委托在组合弹出窗口中绘制项目:

class LineStyleDelegate(QtGui.QItemDelegate):

    def __init__(self, object, parent = None):
        QtGui.QItemDelegate.__init__(self, parent)

    def paint(self, painter, option, index):
        data = index.model().data(index, QtCore.Qt.UserRole)
        if data.isValid() and data.toPyObject() is not None:
            data = data.toPyObject()
            painter.save()

            rect = option.rect
            rect.adjust(+5, 0, -5, 0)

            pen = QtGui.QPen()
            pen.setColor(QtCore.Qt.black)
            pen.setWidth(3)
            pen.setStyle(data)
            painter.setPen(pen)

            middle = (rect.bottom() + rect.top()) / 2

            painter.drawLine(rect.left(), middle, rect.right(), middle)
            painter.restore()

        else:
            QtGui.QItemDelegate.paint(self, painter, option, index)

        painter.drawLine(rect.left(), middle, rect.right(), middle)
        painter.restore()

    else:
        QtGui.QItemDelegate.paint(self, painter, option, index)

paintEvent 以组合方式绘制当前项目。当然,您可以手动绘制它,但是有一种简单的方法可以绘制组合框控件本身(如果您想要当前的箭头按钮或 smth):

def paintEvent(self, e):
    data = self.itemData(self.currentIndex(), QtCore.Qt.UserRole)
    if data.isValid() and data.toPyObject() is not None:
        data = data.toPyObject()
        p = QtGui.QStylePainter(self)
        p.setPen(self.palette().color(QtGui.QPalette.Text))

        opt = QtGui.QStyleOptionComboBox()
        self.initStyleOption(opt)
        p.drawComplexControl(QtGui.QStyle.CC_ComboBox, opt)

        painter = QtGui.QPainter(self)
        painter.save()

        rect = p.style().subElementRect(QtGui.QStyle.SE_ComboBoxFocusRect, opt, self)
        rect.adjust(+5, 0, -5, 0)

        pen = QtGui.QPen()
        pen.setColor(QtCore.Qt.black)
        pen.setWidth(3)
        pen.setStyle(data)
        painter.setPen(pen)

        middle = (rect.bottom() + rect.top()) / 2

        painter.drawLine(rect.left(), middle, rect.right(), middle)
        painter.restore()

    else:
        QtGui.QComboBox.paintEvent(self, e)
于 2010-03-18T09:26:32.640 回答
0

I think I've encountered this problem before, having a delegate that displays the line correctly in the drop-down menu but not in the combo box itself.

The documentation (http://doc.trolltech.com/4.4/qcombobox.html) states that:

"For the text and icon in the combobox label, the data in the model that has the Qt::DisplayRole and Qt::DecorationRole is used."

I suspect that an approach which involves a model that returns suitable data for the DecorationRole might work, but it could be problematic to get it to behave just the way you want it to.

于 2009-02-26T23:15:20.747 回答
0

您还可以将图像保存为图标并使用 QComboBox::setIconSize() 来避免缩放。

于 2009-03-13T19:26:54.807 回答
-1

只需覆盖paintEvent。这是一些草图代码:

void PenComboBox::paintEvent( QPaintEvent* pEvent)
{
  QComboBox::paintEvent( pEvent);
  QVariant itemData = this->itemData( this->currentIndex(), Qt::DisplayRole);
  if( !itemData.isNull() && qVariantCanConvert<QPen>( itemData))
  {
    QPainter painter(this);
    // .. etc
  }
}
于 2009-05-07T21:09:44.783 回答