PyQt5 Fusion Style Button Icons 坏了

Question

我想要一个切换按钮来根据切换状态显示不同的图像。该功能在默认的 QApplication 样式（'WindowsVista'）下运行良好。但是 WindowsVista 风格很丑，我宁愿使用 Fusion 风格。不幸的是，图像在 Fusion Style 中没有改变。

代码：

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 风格（左上按钮，右下按钮）：

融合风格（左上按钮，右下按钮）：

Answer 1

由于source code 中看到的融合风格，这似乎是一种默认行为：

# ...
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一个覆盖此行为的 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_())