使用 QSettings 保存 QRadioButtons 的状态不能在 PyQt5 中正确保存值

Question

我对使用 QSettings 将我的单选按钮状态从一个应用程序会话保存到另一个使用 PyQt5 的结果感到困惑。 (OS = Ubuntu Linux 18.04)

这些是产生莫名其妙结果的步骤：

运行应用；看到两个单选按钮都被选中；两个按钮都会触发，就好像鼠标被选中一样
取消选择顶部单选按钮
关闭应用；查看 'correct' 单选按钮选中状态的保存
运行应用；两个单选按钮都被选中，即使在只选择一个按钮的情况下保存了不同的状态
取消选择顶部单选按钮
关闭应用；查看 'correct' 单选按钮选中状态的保存
在代码中，第18行，将QSettings('LoneProgrammer2', 'qsettingsTest1')改为QSettings('ChangeThis', 'qsettingsTest1')；保存代码
运行应用； !!正确保存的值反映在单选按钮选择中！！
关闭应用； 10 运行应用程序，现在有两个单选按钮再次被选中！

谁能解释一下这是怎么回事？我只想让 QSettings 正常工作。

import sys

from PyQt5.QtCore import QSettings
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QDialogButtonBox, QGroupBox, QHBoxLayout, QRadioButton


class MyApp(QWidget):
    def __init__(self):
        super().__init__()

        self.oAutoPromoteRadioBtn = QRadioButton("Automatically Promote to Queen")
        self.oAutoPromoteRadioBtn.toggled.connect(self.on_selected)

        self.oUsePopupRadioBtn = QRadioButton("Promote Pawn Using Popup Window")
        self.oUsePopupRadioBtn.toggled.connect(self.on_selected)
        self.oUsePopupRadioBtn.setChecked(True)

        self.settings = QSettings('LoneProgrammer2', 'qsettingsTest1')  # companyname, appname 
        self.settings.beginGroup("Promotion Dialog")
        self.oAutoPromoteRadioBtn.setChecked(
            bool(self.settings.value('auto-promote radio button checked state')))
        self.oUsePopupRadioBtn.setChecked(
            bool(self.settings.value('promote using popup radio button checked state')))
        self.settings.endGroup()
        print('AT APP OPENING:')
        print('self.oAutoPromoteRadioBtn.isChecked() = ', self.oAutoPromoteRadioBtn.isChecked())
        print('self.oUsePopupRadioBtn.isChecked() = ', self.oUsePopupRadioBtn.isChecked())

        oVertLayoutForRadioButtons = QVBoxLayout()
        oVertLayoutForRadioButtons.addWidget(self.oAutoPromoteRadioBtn)
        oVertLayoutForRadioButtons.addWidget(self.oUsePopupRadioBtn)

        self.groupbox = QGroupBox("Select pawn promotion method:")
        self.groupbox.setFixedWidth(300)
        self.groupbox.setFixedHeight(95)
        self.groupbox.setLayout(oVertLayoutForRadioButtons)

        self.oVertLayout = QVBoxLayout()
        self.oVertLayout.addWidget(self.groupbox)
        self.setLayout(self.oVertLayout)

    def on_selected(self):
        radio_button = self.sender()

        if radio_button.isChecked():
            if radio_button.text() == 'Automatically Promote to Queen':
                print('set to auto-promote to queen')
            elif radio_button.text() == 'Promote Pawn Using Popup Window':
                print('set to promote pawn to queen using popup window')

    def closeEvent(self, event):
        # save the vars from this session
        self.settings.beginGroup("Promotion Dialog")
        self.settings.setValue('auto-promote radio button checked state', self.oAutoPromoteRadioBtn.isChecked())
        self.settings.setValue('promote using popup radio button checked state', self.oUsePopupRadioBtn.isChecked())
        self.settings.endGroup()

        print()
        print('AT APP CLOSE:')
        print('self.oAutoPromoteRadioBtn.isChecked() = ', self.oAutoPromoteRadioBtn.isChecked())
        print('self.oUsePopupRadioBtn.isChecked() = ', self.oUsePopupRadioBtn.isChecked())


if __name__ == "__main__":
    app = QApplication(sys.argv)

    demo = MyApp()
    demo.show()
    sys.exit(app.exec_())

Answer 1

读取设置值时最好指明类型，因为可能会造成混淆（最有可能的值是 return 使用 bool 时转换为 True 的字符串“true”和“false”，因为它们是真的）。另一方面，为了增加可读性，最好创建专门的方法。

from functools import cached_property
import sys

from PyQt5.QtCore import QSettings
from PyQt5.QtWidgets import (
    QApplication,
    QWidget,
    QVBoxLayout,
    QDialogButtonBox,
    QGroupBox,
    QHBoxLayout,
    QRadioButton,
)


class MyApp(QWidget):
    def __init__(self):
        super().__init__()

        self.oAutoPromoteRadioBtn = QRadioButton("Automatically Promote to Queen")
        self.oAutoPromoteRadioBtn.toggled.connect(self.on_selected)

        self.oUsePopupRadioBtn = QRadioButton("Promote Pawn Using Popup Window")
        self.oUsePopupRadioBtn.toggled.connect(self.on_selected)

        self.settings = QSettings(
            "LoneProgrammer2", "qsettingsTest1"
        )  # companyname, appname

        oVertLayoutForRadioButtons = QVBoxLayout()
        oVertLayoutForRadioButtons.addWidget(self.oAutoPromoteRadioBtn)
        oVertLayoutForRadioButtons.addWidget(self.oUsePopupRadioBtn)

        self.groupbox = QGroupBox("Select pawn promotion method:")
        self.groupbox.setFixedSize(300, 95)
        self.groupbox.setLayout(oVertLayoutForRadioButtons)

        self.oVertLayout = QVBoxLayout(self)
        self.oVertLayout.addWidget(self.groupbox)

        self.read_settings()

    def on_selected(self):
        radio_button = self.sender()

        if radio_button.isChecked():
            if radio_button.text() == "Automatically Promote to Queen":
                print("set to auto-promote to queen")
            elif radio_button.text() == "Promote Pawn Using Popup Window":
                print("set to promote pawn to queen using popup window")

    @cached_property
    def settings(self):
        return QSettings("LoneProgrammer2", "qsettingsTest1")

    @property
    def mapping_settings(self):
        return {
            "Promotion Dialog": [
                ("auto-promote radio button checked state", self.oAutoPromoteRadioBtn),
                (
                    "promote using popup radio button checked state",
                    self.oUsePopupRadioBtn,
                ),
            ]
        }

    def read_settings(self):
        for group_key, values in self.mapping_settings.items():
            self.settings.beginGroup(group_key)
            for (key, checkbox) in values:
                value = self.settings.value(key, type=bool)
                checkbox.setChecked(value)
            self.settings.endGroup()

    def write_settings(self):
        for group_key, values in self.mapping_settings.items():
            self.settings.beginGroup(group_key)
            for (key, checkbox) in values:
                self.settings.setValue(key, checkbox.isChecked())
            self.settings.endGroup()

    def closeEvent(self, event):
        super().closeEvent(event)
        self.write_settings()


if __name__ == "__main__":
    app = QApplication(sys.argv)

    demo = MyApp()
    demo.show()
    sys.exit(app.exec_())

使用 QSettings 保存 QRadioButtons 的状态不能在 PyQt5 中正确保存值

Saving states of QRadioButtons using QSettings not persisting values correctly in PyQt5

python

pyqt

qsettings

pyqt5