PyQt5 Fusion样式按钮图标已损坏

Question

我想要一个切换按钮，根据切换状态显示不同的图像。该功能在默认QApplication样式（“WindowsVista”）中工作正常。但是WindowsVista的风格很难看，我宁愿使用Fusion风格。不幸的是，图像的融合样式没有改变

守则：

from PyQt5.QtWidgets import (QApplication, QMainWindow, QPushButton,
                             QStyleFactory, QLabel)
from PyQt5.QtGui import QIcon
from PyQt5.QtCore import QSize
from PyQt5 import Qt, QtCore
import sys

class Test(QMainWindow):
    def __init__(self, parent=None):
        super(Test, self).__init__(parent=parent)
        self.setGeometry(50,50,300,400)
        
        icon = QIcon()
        icon.addFile('red.png', state = QIcon.Off)
        icon.addFile('green.png', state = QIcon.On)
        button = QPushButton(parent = self)
        button.setCheckable(True)
        button.setIcon(icon)
        button.setIconSize(QSize(150,150))
        button.setGeometry(50,50,200,200)
        
        verString = 'PyQt version: ' + Qt.PYQT_VERSION_STR + '\n'
        verString += 'Qt version: ' + QtCore.qVersion()
        print(verString)
        label = QLabel(verString, parent = self)
        label.setGeometry(50, 250, 200, 150)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    #app.setStyle(QStyleFactory.create('fusion'))
    app.setStyle(QStyleFactory.create('windowsvista'))
    test = Test()        
    test.show()
    sys.exit(app.exec_() )

WindowsVista样式（左上按钮，右下按钮）：

融合风格（左上按钮，右下按钮）：

Answer 1

这似乎是一种默认行为，因为在source code中可以看到融合样式：

# ...
case CE_PushButtonLabel:
    if (const QStyleOptionButton *button = qstyleoption_cast(option)) {
        QStyleOptionButton b(*button);
        // no PM_ButtonShiftHorizontal and PM_ButtonShiftVertical for fusion style
        b.state &= ~(State_On | State_Sunken);
        QCommonStyle::drawControl(element, &b, painter, widget);
    }
    break;
// ...

一种可能的解决方案是实现覆盖此行为的QProxyStyle：

import sys

from PyQt5.QtCore import QSize, qVersion, PYQT_VERSION_STR
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import (
    QApplication,
    QMainWindow,
    QPushButton,
    QStyleFactory,
    QLabel,
    QProxyStyle,
    QStyle,
    QCommonStyle,
)


class ProxyStyle(QProxyStyle):
    def drawControl(self, control, option, painter, widget):
        if control == QStyle.CE_PushButtonLabel:
            QCommonStyle.drawControl(self, control, option, painter, widget)
        else:
            super().drawControl(control, option, painter, widget)


class Test(QMainWindow):
    def __init__(self, parent=None):
        super(Test, self).__init__(parent=parent)
        self.setGeometry(50, 50, 300, 400)

        icon = QIcon()
        icon.addFile("red.png", state=QIcon.Off)
        icon.addFile("green.png", state=QIcon.On)
        button = QPushButton(parent=self)
        button.setCheckable(True)
        button.setIcon(icon)
        button.setIconSize(QSize(150, 150))
        button.setGeometry(50, 50, 200, 200)

        verString = "PyQt version: " + PYQT_VERSION_STR + "\n"
        verString += "Qt version: " + qVersion()
        print(verString)
        label = QLabel(verString, parent=self)
        label.setGeometry(50, 250, 200, 150)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    app.setStyle(QStyleFactory.create("fusion"))
    proxy = ProxyStyle(app.style())
    app.setStyle(proxy)
    test = Test()
    test.show()
    sys.exit(app.exec_())