Python numeric keypad with PyQt - Button grid

Python PyQt Widgets: Exercise-10 with Solution

Write a Python program to create push buttons in a grid where each button represents a numeric keypad. Use PyQt module.

From doc.qt.io:

QApplication Class: The QApplication class manages the GUI application's control flow and main settings.

QMainWindow Class: The QMainWindow class provides a main application window.

QWidget Class: The QWidget class is the base class of all user interface objects.

QGridLayout Class: The QGridLayout class lays out widgets in a grid.

QPushButton Class: The QPushButton widget provides a command button.

Sample Solution:

Python Code:

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QGridLayout, QPushButton
class NumericKeypadApp(QMainWindow):
    def __init__(self):
        super().__init__()

        # Set the window properties (title and initial size)
        self.setWindowTitle("Numeric Keypad")
        self.setGeometry(100, 100, 300, 400)  # (x, y, width, height)

        # Create a central widget for the main window
        central_widget = QWidget()
        self.setCentralWidget(central_widget)

        # Create a QGridLayout for arranging the buttons
        grid_layout = QGridLayout()

        # Create numeric keypad buttons (0-9)
        for i in range(10):
            button = QPushButton(str(i))
            button.clicked.connect(lambda _, ch=i: self.on_button_click(ch))  # Use a lambda to pass the value
            grid_layout.addWidget(button, i // 3, i % 3)

        # Create a layout for the central widget
        layout = QGridLayout()
        layout.addLayout(grid_layout, 0, 0)

        # Set the layout for the central widget
        central_widget.setLayout(layout)

    def on_button_click(self, value):
        # Handle button click event (for demonstration, print the clicked value)
        print(f"Button {value} clicked!")

def main():
    app = QApplication(sys.argv)
    window = NumericKeypadApp()
    window.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

Explanation:

In the exercise above -

• Import the necessary modules.
• Create a "QMainWindow" named "NumericKeypadApp" with a central widget.
• Set the window's title and initial size.
• Create a "QGridLayout" named grid_layout to arrange the numeric keypad buttons in a grid.
• Create numeric keypad buttons (0-9) in a loop and connect their click events to the on_button_click method, passing the button's value as an argument.
• The "on_button_click()" method handles button click events. For demonstration purposes, it prints the clicked value.
• Arrange the numeric keypad buttons using the "QGridLayout".
• In the main function, we create the PyQt application, create an instance of the "NumericKeypadApp" class, show the window, and run the application's event loop.

Output:

Button 7 clicked!
Button 1 clicked!
Button 0 clicked!
Button 1 clicked!
Button 5 clicked!

Flowchart:

Python Code Editor:

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