无法从ini fi读取布尔值

Question

从PyQt5应用程序中的ini文件加载布尔值时出现问题。在

#!/usr/bin/python3
# -*- coding: utf-8 -*-

import sys
from PyQt5 import QtCore
from PyQt5.QtCore import QSettings, QVariant
from PyQt5.QtWidgets import (
    QApplication, QCheckBox, QDialog, QGridLayout,
    QLabel, QLayout, QPushButton
)


class Settings(QDialog):
    "settings GUI"

    _settings = None

    def __init__(self):
        super(Settings, self).__init__()
        self._ui()

    def _ui(self):
        self._chk_test = QCheckBox()
        self._chk_test.setText("test checkbox")

        self._settings = QSettings("settings.ini", QSettings.IniFormat)
        self._settings.setFallbacksEnabled(False)

        # load configuration
        self._chk_test.setChecked(
            self._bool(self._settings.value("test_value", True)))

        # save settings
        btn_save = QPushButton("save")
        btn_save.clicked.connect(self._save_settings)

        # setting layouts
        grid_layout = QGridLayout()
        grid_layout.addWidget(self._chk_test, 0, 0, 1, 1)
        grid_layout.addWidget(btn_save, 0, 1, 1, 1)
        grid_layout.setSizeConstraint(QLayout.SetFixedSize)
        grid_layout.setHorizontalSpacing(100)
        grid_layout.setVerticalSpacing(5)

        self.setWindowTitle("Boolean")
        self.setLayout(grid_layout)
        self.show()

    def _save_settings(self):
        self._settings.setValue("test_value", self._chk_test.isChecked())
        self.close()

    def _bool(self, str):
        if str == "true":
            return True
        else:
            return False


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ui = Settings()
    sys.exit(app.exec_())

当我试图使用

^{pr2}$

或者

QVariant(self._settings.value("test_value", True)).toBool()

我得到了AttributeError：

'str' / 'QVariant' object has no attribute 'toBool()'. 

我已经编写了自定义_bool方法，但我想知道是否有更好的方法来解决它。在

Answer 1

假设self._settings.value("test_value", True)返回一个值为"true"的字符串，可以这样做

self._chk_test.setChecked(
            self._settings.value("test_value", True) == "true")

但是，如果您需要多次执行此操作，我将保留自定义方法（但要像@furas建议的那样使其更紧凑）：

^{pr2}$

Answer 2

它们添加第三个参数type=来设置结果的类型。所以您可以使用type=bool并获得PythonTrue/False，而不是字符串"true"/"false"

a = self._settings.value("test_value", True, type=bool)
print('a:', type(a), a)

b = self._settings.value("test_value", True)
print('b:', type(b), b)

结果

^{pr2}$

---

在谷歌找到：https://riverbankcomputing.com/pipermail/pyqt/2011-January/029032.html

• Added the optional type keyword argument to QSettings.value() to allow the type of the returned value to be specified.