pyqt/further/mvc_1.py

import sys

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QMainWindow, QFormLayout, QLineEdit, QSpinBox, QComboBox, QPushButton, QApplication, QWidget

model = {
    "name": "Johnina Smith",
    "age": 10,
    "favorite_icecream": "Vanilla",
}


class MainWindow(QMainWindow):

    def __init__(self):
        super().__init__()
        self.setWindowTitle("MVC Example")

        layout = QFormLayout()

        # Dictionary to store the form data, with default data.
        self.name = QLineEdit()
        self.name.setText(model["name"])
        self.name.textChanged.connect(self.on_name_changed)
        self.age = QSpinBox()
        self.age.setRange(0, 200)
        self.age.setValue(model["age"])
        self.age.valueChanged.connect(self.on_age_changed)
        self.icecream = QComboBox()
        self.icecream.addItems(["Vanilla", "Strawberry", "Chocolate"])
        self.icecream.setCurrentText(model["favorite_icecream"])
        self.icecream.currentTextChanged.connect(self.on_icecream_changed)
        self.save_btn = QPushButton("Save")
        self.restore_btn = QPushButton("Restore")

        layout.addRow("Name", self.name)
        layout.addRow("Age", self.age)
        layout.addRow("Favorite Ice Cream", self.icecream)
        layout.addRow(self.save_btn)
        layout.addRow(self.restore_btn)
        layout.setLabelAlignment(Qt.AlignLeft)

        widget = QWidget()
        widget.setLayout(layout)
        self.setCentralWidget(widget)

    def on_name_changed(self, value):
        model["name"] = value
        print(model)

    def on_age_changed(self, value):
        model["age"] = value
        print(model)

    def on_icecream_changed(self, value):
        model["favorite_icecream"] = value
        print(model)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    app.exec_()