PyQt5 - Lesson 004. Using QSettings

PyQt5, QSettings, Qt, python

See Using QSettings in PyQt5. I propose to write a small application, which will be a single check box, the state of which we will save in the settings. Status checkbox will be saved by clicking on the checkbox. After closing the program and re-open this checkbox will be put to the state in which it was at the close of the program.

main .py

from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QCheckBox, QGridLayout, QLabel, QSpacerItem, \
    QSizePolicy
from PyQt5.QtCore import QSize, QCoreApplication, QSettings
 
 
ORGANIZATION_NAME = 'Example App'
ORGANIZATION_DOMAIN = 'example.com'
APPLICATION_NAME = 'QSettings program'
SETTINGS_TRAY = 'settings/tray'
 
 
class MainWindow(QMainWindow):
    """
         Checkbox.
         Will initialize in the constructor.
    """
    check_box = None
 
    # Override the class constructor
    def __init__(self):
        # Be sure to call the super class method
        QMainWindow.__init__(self)
 
        self.setMinimumSize(QSize(480, 240))  # Set sizes
        self.setWindowTitle("Settings Application")  # Set a title
        central_widget = QWidget(self)  # Create a central widget
        self.setCentralWidget(central_widget)  # Set the central widget
 
        grid_layout = QGridLayout()  # Create a QGridLayout
        central_widget.setLayout(grid_layout)  # Set the layout into the central widget
        grid_layout.addWidget(QLabel("Application, which can minimize to Tray", self), 0, 0)
 
        # Add a checkbox, which will depend on the behavior of the program when the window is closed
        self.check_box = QCheckBox('Settings CheckBox for minimizing to tray')
        grid_layout.addWidget(self.check_box, 1, 0)
        grid_layout.addItem(QSpacerItem(0, 0, QSizePolicy.Expanding, QSizePolicy.Expanding), 2, 0)
 
        # Get settings
        settings = QSettings()
        # Get checkbox state with speciying type of checkbox:
        # type=bool is a replacement of toBool() in PyQt5
        check_state = settings.value(SETTINGS_TRAY, False, type=bool)
        # Set state
        self.check_box.setChecked(check_state)
        # connect the slot to the signal by clicking the checkbox to save the state settings
        self.check_box.clicked.connect(self.save_check_box_settings)
 
    # Slot checkbox to save the settings
    def save_check_box_settings(self):
        settings = QSettings()
        settings.setValue(SETTINGS_TRAY, self.check_box.isChecked())
        settings.sync()
 
 
if __name__ == "__main__":
    import sys
 
    # To ensure that every time you call QSettings not enter the data of your application, 
    # which will be the settings, you can set them globally for all applications
    QCoreApplication.setApplicationName(ORGANIZATION_NAME)
    QCoreApplication.setOrganizationDomain(ORGANIZATION_DOMAIN)
    QCoreApplication.setApplicationName(APPLICATION_NAME)
 
    app = QApplication(sys.argv)
    mw = MainWindow()
    mw.show()
    sys.exit(app.exec())