Python PyQt button actions example

Python PyQt Connecting Signals to Slots: Exercise-2 with Solution

Write a Python program that builds a PyQt application with two push buttons. Connect each button to a different slot function, and when clicked, have each button perform a unique action.

From doc.qt.io:

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

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

QPushButton Class: The QPushButton widget provides a command button.

QMessageBox Class: The QMessageBox class provides a modal dialog for informing the user or for asking the user a question and receiving an answer.

Sample Solution:

Python Code:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QMessageBox

# Slot function for the first button
def action_one(window):
    QMessageBox.information(window, "Button 1", "Clicked Button 1!")

# Slot function for the second button
def action_two(window):
    QMessageBox.information(window, "Button 2", "Clicked Button 2!")

def main():
    app = QApplication(sys.argv)

    # Create the main window
    window = QWidget()
    window.setWindowTitle("PyQt Button Actions")
    window.setGeometry(100, 100, 400, 200)  # (x, y, width, height)

    # Create the first push button
    button1 = QPushButton("Button 1", window)
    button1.setGeometry(100, 80, 100, 40)  # (x, y, width, height)

    # Create the second push button
    button2 = QPushButton("Button 2", window)
    button2.setGeometry(200, 80, 100, 40)  # (x, y, width, height)

    # Connect the first button's clicked signal to action_one slot
    button1.clicked.connect(lambda: action_one(window))

    # Connect the second button's clicked signal to action_two slot
    button2.clicked.connect(lambda: action_two(window))

    # Show the main window
    window.show()

    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

Explanation:

In the exercise above -

• Import the necessary modules from PyQt5.
• We define a custom "QWidget" class named "ButtonActions" that inherits from "QWidget". This class contains the entire GUI application logic.
• Inside the "ButtonActions" class, we create the main window and the two "QPushButton" widgets (button1 and button2).
• We connect the clicked signal of each button to its respective slot function using self.button1.clicked.connect(self.action_one) and self.button2.clicked.connect(self.action_two).
• The "action_one()" and "action_two()" slot functions display unique message boxes when called.
• In the main function, we create the PyQt application, instantiate the "ButtonActions" class, and show the main window.

Output:

Flowchart:

Python Code Editor:

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