PyQt4:如何将数字调整框按钮方向修改为左侧和右侧

Question

我找到了一个C++示例，它修改了左、右的QSPIN BOOK按钮方向，并且它工作。所以我用PyQt-4.7来模拟这个例子，但是按钮没有显示。以下是我的代码：

from PyQt4 import QtGui, QtCore
from PyQt4.QtGui import QStyle, QCommonStyle

class ScientificDoubleSpinBox(QtGui.QDoubleSpinBox):
    def __init__(self, *args, **kwargs):
        super(ScientificDoubleSpinBox, self).__init__(*args, **kwargs)
        self.setMinimum(0)
        self.setMaximum(1000)
        self.setDecimals(1000)
        style = SpinBoxStyle()
        #here
        self.setStyle(style)

class SpinBoxStyle(QtGui.QCommonStyle):

    def __init__(self):
        super(SpinBoxStyle, self).__init__()

    def drawComplexControl(self, control, option, painter, widget = None):
        if(control == QtGui.QStyle.CC_SpinBox):
            self.drawSpinBoxButton(QtGui.QStyle.SC_SpinBoxDown,option,painter);
            self.drawSpinBoxButton(QtGui.QStyle.SC_SpinBoxUp,option,painter);
            rect = self.subControlRect(QtGui.QStyle.CC_SpinBox,option,QtGui.QStyle.SC_SpinBoxEditField, widget).adjusted(-1,0,+1,0)
            painter.setPen(QtGui.QPen(option.palette.mid(),1.0))
            painter.drawLine(rect.topLeft(),rect.bottomLeft())
            painter.drawLine(rect.topRight(),rect.bottomRight())
        else:
            return QCommonStyle().drawComplexControl(which,option,painter)             

    def drawSpinBoxButton(self, subControl, option, painter, widget = None):
        buttonWidth = 16
        arrow = QtGui.QStyle.PE_IndicatorSpinDown
        buttonRect = option.rect
        if((subControl==QtGui.QStyle.SC_SpinBoxUp)!=(option.direction==1)): #Qt.RightToLeft
            arrow = QtGui.QStyle.PE_IndicatorSpinUp
            buttonRect.translate(buttonRect.width()/2,0)
        else:
            buttonRect.translate(buttonRect.width()/2-buttonWidth,0)

        buttonRect.setWidth((buttonRect.width()+1)*2);
        #????
        #buttonOpt = qstyleoption_cast(option)
        buttonOpt = QtGui.QStyleOption(option)

        painter.save()
        painter.setClipRect(buttonRect, 2) #Qt.IntersectClip
        #????
        #if(not(option.activeSubControls & subControl)):  
            #buttonOpt.state &=not(QtGui.QStyle.State_MouseOver|QtGui.QStyle.State_On|QtGui.QStyle.State_Sunken)

        arrowOpt= QtGui.QStyleOption(buttonOpt)
        arrowOpt.rect = self.subControlRect(QtGui.QStyle.CC_SpinBox,option,subControl, widget);
        if(arrowOpt.rect.isValid()):
            self.drawPrimitive(arrow,arrowOpt,painter)
        painter.restore()

    def subControlRect(self, whichControl, option, whichSubControl, widget):
        if(whichControl==QtGui.QStyle.CC_SpinBox):
            frameWidth = self.pixelMetric(QtGui.QStyle.PM_DefaultFrameWidth, option, widget)
            buttonWidth = 16;
            if whichSubControl == QtGui.QStyle.SC_SpinBoxFrame:
                return option.rect
            elif whichSubControl == QtGui.QStyle.SC_SpinBoxEditField:
                return option.rect.adjusted(0, +frameWidth,-buttonWidth*4,-frameWidth)
            elif whichControl == QtGui.QStyle.SC_SpinBoxDown:
                return self.visualRect(option.direction, option.rect, QtCore.QRect(option.rect.right()-buttonWidth*2,
                                                    option.rect.y(), buttonWidth, option.rect.height()))
            elif whichControl == QtGui.QStyle.SC_SpinBoxUp:
                return self.visualRect(option.direction, option.rect, QtCore.QRect(option.rect.right()-buttonWidth,
                                                    option.rect.y(), buttonWidth, option.rect.height()))
            else:
                return QtCore.QRect()
        else:
            return QCommonStyle.subControlRect(whichControl,option,whichSubControl)