如何保存和恢复每个小部件实例唯一的小部件属性？
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【中文标题】如何保存和恢复每个小部件实例唯一的小部件属性？【英文标题】：How to save and restore widget properties that is unique for each instance of the widget? 【发布时间】：2020-10-05 05:31:55 【问题描述】：我希望能够在我的 PyQt5 应用程序中保存和恢复小部件状态（属性和值）。小部件状态应保存到 .ini 文件中。这已在以下 *** 答案中得到证明：
How to save text in QLineEdits in PyQt even if the Widget gets closed? Loading Widgets properly while restoring from QSettings但是，上述问题的答案并没有解决我在下面的示例代码中面临的特定问题。我希望设置 .ini 文件的保存和恢复对于正在运行的父小部件（主窗口应用程序）的每个实例都是唯一的。因此，在保存小部件属性时，对所有小部件的迭代应该只发生在父小部件（主窗口）的子小部件上，而不是遍历当前在全局应用程序中运行的所有小部件。
我认为下面示例代码中的问题与for w in QtWidgets.qApp.allWidgets(): 行有关。我认为这一行会遍历 PyQt5 全局应用程序中当前打开的所有小部件。但是，当同一个父widget有多个实例时，objectName会出现重复。尽管可以在 init() 期间为每个实例指定一个唯一名称（例如：app_name）并在 QSettings 键中进行说明，但这可能不是最好的普遍适用的解决方案。因此，我该如何解决我面临的问题？如何让settings_save() 函数遍历父小部件（主窗口应用程序）实例的所有子小部件，而不是遍历当前在全局应用程序中运行的所有父小部件？在 Qt 文档中，我找不到类似于 allWidgets() 的函数，它允许我指定父窗口小部件（例如：QMainWindow）并给我它下面的所有窗口小部件和对象。如果可以在父小部件中获取所有小部件，那么我可以轻松修改函数settings_save()，不仅包括 QSetting 变量作为参数，还包括我要为其保存设置的小部件实例。
main_app.py
import sys
from PyQt5 import QtWidgets, uic, QtCore, QtGui
from PyQt5.QtCore import QFileInfo, QSettings, QObject
from PyQt5.QtWidgets import qApp
from ui_mainwindow import Ui_MainWindow
def settings_value_is_valid(val):
# https://***.com/a/60028282/4988010
if isinstance(val, QtGui.QPixmap):
return not val.isNull()
return True
def settings_restore(settings):
# https://***.com/a/60028282/4988010
finfo = QtCore.QFileInfo(settings.fileName())
if finfo.exists() and finfo.isFile():
for w in QtWidgets.qApp.allWidgets():
if w.objectName() and not w.objectName().startswith("qt_"):
# if w.objectName():
mo = w.metaObject()
for i in range(mo.propertyCount()):
prop = mo.property(i)
name = prop.name()
last_value = w.property(name)
key = "/".format(w.objectName(), name)
# print(prop, name, last_value, key)
if not settings.contains(key):
continue
val = settings.value(key, type=type(last_value),)
if (
val != last_value
and settings_value_is_valid(val)
and prop.isValid()
and prop.isWritable()
):
w.setProperty(name, val)
def settings_save(settings):
# https://***.com/a/60028282/4988010
for w in QtWidgets.qApp.allWidgets():
if w.objectName() and not w.objectName().startswith("qt_"):
# if w.objectName():
mo = w.metaObject()
for i in range(mo.propertyCount()):
prop = mo.property(i)
name = prop.name()
key = "/".format(w.objectName(), name)
val = w.property(name)
if settings_value_is_valid(val) and prop.isValid() and prop.isWritable():
settings.setValue(key, w.property(name))
class MyApp(QtWidgets.QMainWindow):
def __init__(self, app_name='DefaultAppName'):
super(MyApp, self).__init__()
self.settings = QSettings("./temp/gui_settings-.ini".format(app_name), QSettings.IniFormat)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
# Set window titlte and qlineedit to indicate the name of app instance
self.ui.app_instance_name.setText(app_name)
self.setWindowTitle(app_name)
# Load the saved config file saved from previous app usage
self.config_widgets_load_settings()
self.ui.action_save_current_config.triggered.connect(self.config_widgets_save_settings)
self.ui.action_load_config.triggered.connect(self.config_widgets_load_settings)
self.ui.action_clear_config_file.triggered.connect(self.config_clear_settings)
def config_widgets_save_settings(self):
# Write current state to the settings config file
settings_save(self.settings)
def config_widgets_load_settings(self):
# Load settings config file
settings_restore(self.settings)
def config_clear_settings(self):
# Clear the settings config file
self.settings.clear()
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
# First instance of the MyApp
app_one = MyApp(app_name='App#1')
app_one.show()
# Second instance of the MyApp
app_two = MyApp(app_name='App#2')
app_two.show()
app.exec_()
ui_mainwindow.py
from PyQt5 import QtCore, QtGui, QtWidgets
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(330, 202)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.gridLayoutWidget = QtWidgets.QWidget(self.centralwidget)
self.gridLayoutWidget.setGeometry(QtCore.QRect(20, 80, 291, 51))
self.gridLayoutWidget.setObjectName("gridLayoutWidget")
self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
self.gridLayout.setContentsMargins(0, 0, 0, 0)
self.gridLayout.setObjectName("gridLayout")
self.lineEdit1 = QtWidgets.QLineEdit(self.gridLayoutWidget)
self.lineEdit1.setObjectName("lineEdit1")
self.gridLayout.addWidget(self.lineEdit1, 2, 0, 1, 1)
self.pushButton1 = QtWidgets.QPushButton(self.gridLayoutWidget)
self.pushButton1.setCheckable(True)
self.pushButton1.setObjectName("pushButton1")
self.gridLayout.addWidget(self.pushButton1, 2, 1, 1, 1)
self.spinBox1 = QtWidgets.QSpinBox(self.gridLayoutWidget)
self.spinBox1.setMaximum(10000)
self.spinBox1.setProperty("value", 37)
self.spinBox1.setObjectName("spinBox1")
self.gridLayout.addWidget(self.spinBox1, 2, 2, 1, 1)
self.label = QtWidgets.QLabel(self.gridLayoutWidget)
self.label.setObjectName("label")
self.gridLayout.addWidget(self.label, 1, 0, 1, 3)
self.horizontalLayoutWidget = QtWidgets.QWidget(self.centralwidget)
self.horizontalLayoutWidget.setGeometry(QtCore.QRect(50, 20, 241, 31))
self.horizontalLayoutWidget.setObjectName("horizontalLayoutWidget")
self.horizontalLayout = QtWidgets.QHBoxLayout(self.horizontalLayoutWidget)
self.horizontalLayout.setContentsMargins(0, 0, 0, 0)
self.horizontalLayout.setObjectName("horizontalLayout")
self.label_2 = QtWidgets.QLabel(self.horizontalLayoutWidget)
self.label_2.setObjectName("label_2")
self.horizontalLayout.addWidget(self.label_2)
self.app_instance_name = QtWidgets.QLineEdit(self.horizontalLayoutWidget)
self.app_instance_name.setObjectName("app_instance_name")
self.horizontalLayout.addWidget(self.app_instance_name)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 330, 21))
self.menubar.setObjectName("menubar")
self.menuFile = QtWidgets.QMenu(self.menubar)
self.menuFile.setObjectName("menuFile")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.action_save_current_config = QtWidgets.QAction(MainWindow)
self.action_save_current_config.setObjectName("action_save_current_config")
self.action_load_config = QtWidgets.QAction(MainWindow)
self.action_load_config.setObjectName("action_load_config")
self.action_clear_config_file = QtWidgets.QAction(MainWindow)
self.action_clear_config_file.setObjectName("action_clear_config_file")
self.menuFile.addAction(self.action_save_current_config)
self.menuFile.addAction(self.action_load_config)
self.menuFile.addAction(self.action_clear_config_file)
self.menubar.addAction(self.menuFile.menuAction())
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.lineEdit1.setText(_translate("MainWindow", "This is default text"))
self.pushButton1.setText(_translate("MainWindow", "Push me"))
self.label.setText(_translate("MainWindow", "My simple app with various widgets"))
self.label_2.setText(_translate("MainWindow", "App instance name"))
self.menuFile.setTitle(_translate("MainWindow", "File"))
self.action_save_current_config.setText(_translate("MainWindow", "Save current config"))
self.action_load_config.setText(_translate("MainWindow", "Load config"))
self.action_clear_config_file.setText(_translate("MainWindow", "Clear config file"))
if __name__ == "__main__":
import sys
app = QtWidgets.QApplication(sys.argv)
MainWindow = QtWidgets.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
【问题讨论】：
【参考方案1】：在进一步研究 Qt 文档后，我找到了解决方案。每个QWidget 都是QObject 类型，它有一个名为findChildren() 的方法。此方法可用于指定要为其保存/恢复设置的父窗口小部件。
以下是创建的有助于保存/恢复设置的方法。我的贡献是创建函数settings_get_all_widgets()。保存/恢复功能最初是由@eyllanesc 创建的，我为解决这个问题而对其进行了修改。
def settings_get_all_widgets(parent):
# Possible fix to the issue:
# https://***.com/questions/64202927/how-to-save-and-restore-widget-properties-that-is-unique-for-each-instance-of-th
if parent:
# Find all children inside the given parent that is of type QWidget
all_widgets = parent.findChildren(QtWidgets.QWidget)
if parent.isWidgetType():
# If parent is of type QWidget, add the parent itself to the list
all_widgets.append(parent)
else:
# If no parent is given then get all the widgets from all the PyQt applications
all_widgets = QtWidgets.qApp.allWidgets()
return all_widgets
def settings_value_is_valid(val):
# Originally adapted from:
# https://***.com/a/60028282/4988010
# https://github.com/eyllanesc/***/issues/26#issuecomment-703184281
if isinstance(val, QtGui.QPixmap):
return not val.isNull()
return True
def settings_restore(settings, parent=None):
# Originally adapted from:
# https://***.com/a/60028282/4988010
# https://github.com/eyllanesc/***/issues/26#issuecomment-703184281
if not settings:
return
all_widgets = settings_get_all_widgets(parent)
finfo = QtCore.QFileInfo(settings.fileName())
if finfo.exists() and finfo.isFile():
for w in all_widgets:
if w.objectName() and not w.objectName().startswith("qt_"):
# if w.objectName():
mo = w.metaObject()
for i in range(mo.propertyCount()):
prop = mo.property(i)
name = prop.name()
last_value = w.property(name)
key = "/".format(w.objectName(), name)
if not settings.contains(key):
continue
val = settings.value(key, type=type(last_value),)
if (
val != last_value
and settings_value_is_valid(val)
and prop.isValid()
and prop.isWritable()
):
w.setProperty(name, val)
def settings_save(settings, parent=None):
# Originally adapted from:
# https://***.com/a/60028282/4988010
# https://github.com/eyllanesc/***/issues/26#issuecomment-703184281
if not settings:
return
all_widgets = settings_get_all_widgets(parent)
for w in all_widgets:
if w.objectName() and not w.objectName().startswith("qt_"):
mo = w.metaObject()
for i in range(mo.propertyCount()):
prop = mo.property(i)
name = prop.name()
key = "/".format(w.objectName(), name)
val = w.property(name)
if settings_value_is_valid(val) and prop.isValid() and prop.isWritable():
settings.setValue(key, w.property(name))
以下是包含原始问题解决方案的自包含工作代码。
import sys
from PyQt5 import QtWidgets, uic, QtCore, QtGui
from PyQt5.QtCore import QFileInfo, QSettings, QObject
from PyQt5.QtWidgets import qApp
# from ui_mainwindow import Ui_MainWindow
def settings_get_all_widgets(parent):
# Possible fix to the issue:
# https://***.com/questions/64202927/how-to-save-and-restore-widget-properties-that-is-unique-for-each-instance-of-th
if parent:
# Find all children inside the given parent that is of type QWidget
all_widgets = parent.findChildren(QtWidgets.QWidget)
if parent.isWidgetType():
# If parent is of type QWidget, add the parent itself to the list
all_widgets.append(parent)
else:
# If no parent is given then get all the widgets from all the PyQt applications
all_widgets = QtWidgets.qApp.allWidgets()
return all_widgets
def settings_value_is_valid(val):
# Originally adapted from:
# https://***.com/a/60028282/4988010
# https://github.com/eyllanesc/***/issues/26#issuecomment-703184281
if isinstance(val, QtGui.QPixmap):
return not val.isNull()
return True
def settings_restore(settings, parent=None):
# Originally adapted from:
# https://***.com/a/60028282/4988010
# https://github.com/eyllanesc/***/issues/26#issuecomment-703184281
if not settings:
return
all_widgets = settings_get_all_widgets(parent)
finfo = QtCore.QFileInfo(settings.fileName())
if finfo.exists() and finfo.isFile():
for w in all_widgets:
if w.objectName() and not w.objectName().startswith("qt_"):
# if w.objectName():
mo = w.metaObject()
for i in range(mo.propertyCount()):
prop = mo.property(i)
name = prop.name()
last_value = w.property(name)
key = "/".format(w.objectName(), name)
if not settings.contains(key):
continue
val = settings.value(key, type=type(last_value),)
if (
val != last_value
and settings_value_is_valid(val)
and prop.isValid()
and prop.isWritable()
):
w.setProperty(name, val)
def settings_save(settings, parent=None):
# Originally adapted from:
# https://***.com/a/60028282/4988010
# https://github.com/eyllanesc/***/issues/26#issuecomment-703184281
if not settings:
return
all_widgets = settings_get_all_widgets(parent)
for w in all_widgets:
if w.objectName() and not w.objectName().startswith("qt_"):
mo = w.metaObject()
for i in range(mo.propertyCount()):
prop = mo.property(i)
name = prop.name()
key = "/".format(w.objectName(), name)
val = w.property(name)
if settings_value_is_valid(val) and prop.isValid() and prop.isWritable():
settings.setValue(key, w.property(name))
class MyApp(QtWidgets.QMainWindow):
def __init__(self, app_name='DefaultAppName'):
super(MyApp, self).__init__()
self.settings = QSettings("./temp/gui_settings-.ini".format(app_name), QSettings.IniFormat)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
# Set window titlte and qlineedit to indicate the name of app instance
self.ui.app_instance_name.setText(app_name)
self.setWindowTitle(app_name)
# Load the saved config file saved from previous app usage
self.config_widgets_load_settings()
self.ui.action_save_current_config.triggered.connect(self.config_widgets_save_settings)
self.ui.action_load_config.triggered.connect(self.config_widgets_load_settings)
self.ui.action_clear_config_file.triggered.connect(self.config_clear_settings)
def config_widgets_save_settings(self):
# Write current state to the settings config file
settings_save(self.settings, self)
def config_widgets_load_settings(self):
# Load settings config file
settings_restore(self.settings, self)
def config_clear_settings(self):
# Clear the settings config file
self.settings.clear()
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName("MainWindow")
MainWindow.resize(330, 202)
self.centralwidget = QtWidgets.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.gridLayoutWidget = QtWidgets.QWidget(self.centralwidget)
self.gridLayoutWidget.setGeometry(QtCore.QRect(20, 80, 291, 51))
self.gridLayoutWidget.setObjectName("gridLayoutWidget")
self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
self.gridLayout.setContentsMargins(0, 0, 0, 0)
self.gridLayout.setObjectName("gridLayout")
self.lineEdit1 = QtWidgets.QLineEdit(self.gridLayoutWidget)
self.lineEdit1.setObjectName("lineEdit1")
self.gridLayout.addWidget(self.lineEdit1, 2, 0, 1, 1)
self.pushButton1 = QtWidgets.QPushButton(self.gridLayoutWidget)
self.pushButton1.setCheckable(True)
self.pushButton1.setObjectName("pushButton1")
self.gridLayout.addWidget(self.pushButton1, 2, 1, 1, 1)
self.spinBox1 = QtWidgets.QSpinBox(self.gridLayoutWidget)
self.spinBox1.setMaximum(10000)
self.spinBox1.setProperty("value", 37)
self.spinBox1.setObjectName("spinBox1")
self.gridLayout.addWidget(self.spinBox1, 2, 2, 1, 1)
self.label = QtWidgets.QLabel(self.gridLayoutWidget)
self.label.setObjectName("label")
self.gridLayout.addWidget(self.label, 1, 0, 1, 3)
self.horizontalLayoutWidget = QtWidgets.QWidget(self.centralwidget)
self.horizontalLayoutWidget.setGeometry(QtCore.QRect(50, 20, 241, 31))
self.horizontalLayoutWidget.setObjectName("horizontalLayoutWidget")
self.horizontalLayout = QtWidgets.QHBoxLayout(self.horizontalLayoutWidget)
self.horizontalLayout.setContentsMargins(0, 0, 0, 0)
self.horizontalLayout.setObjectName("horizontalLayout")
self.label_2 = QtWidgets.QLabel(self.horizontalLayoutWidget)
self.label_2.setObjectName("label_2")
self.horizontalLayout.addWidget(self.label_2)
self.app_instance_name = QtWidgets.QLineEdit(self.horizontalLayoutWidget)
self.app_instance_name.setObjectName("app_instance_name")
self.horizontalLayout.addWidget(self.app_instance_name)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtWidgets.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 330, 21))
self.menubar.setObjectName("menubar")
self.menuFile = QtWidgets.QMenu(self.menubar)
self.menuFile.setObjectName("menuFile")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtWidgets.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.action_save_current_config = QtWidgets.QAction(MainWindow)
self.action_save_current_config.setObjectName("action_save_current_config")
self.action_load_config = QtWidgets.QAction(MainWindow)
self.action_load_config.setObjectName("action_load_config")
self.action_clear_config_file = QtWidgets.QAction(MainWindow)
self.action_clear_config_file.setObjectName("action_clear_config_file")
self.menuFile.addAction(self.action_save_current_config)
self.menuFile.addAction(self.action_load_config)
self.menuFile.addAction(self.action_clear_config_file)
self.menubar.addAction(self.menuFile.menuAction())
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
self.lineEdit1.setText(_translate("MainWindow", "This is default text"))
self.pushButton1.setText(_translate("MainWindow", "Push me"))
self.label.setText(_translate("MainWindow", "My simple app with various widgets"))
self.label_2.setText(_translate("MainWindow", "App instance name"))
self.menuFile.setTitle(_translate("MainWindow", "File"))
self.action_save_current_config.setText(_translate("MainWindow", "Save current config"))
self.action_load_config.setText(_translate("MainWindow", "Load config"))
self.action_clear_config_file.setText(_translate("MainWindow", "Clear config file"))
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
# First instance of the MyApp
app_one = MyApp(app_name='App#1')
app_one.show()
# Second instance of the MyApp
app_two = MyApp(app_name='App#2')
app_two.show()
app.exec_()
【讨论】：
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