Python PyQt button click example

Python PyQt Connecting Signals to Slots: Exercise-1 with Solution

Write a Python program that creates a PyQt application with a push button. Display a message when the push button is clicked.

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
# Define a slot function to display a message when the button is clicked
def show_message():
    message_box = QMessageBox()
    message_box.setWindowTitle("Message")
    message_box.setText("Button clicked!")
    message_box.exec_()

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

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

    # Create a push button
    button = QPushButton("Click me!", window)
    button.setGeometry(150, 80, 100, 40)  # (x, y, width, height)

    # Connect the button's clicked signal to the show_message slot
    button.clicked.connect(show_message)

    # 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.
• Define a slot function named "show_message()" that creates a QMessageBox to display a message when called.
• In the main function, create the PyQt application and the main window.
• Create a "QPushButton" widget labeled "Click me!" and set its geometry (position and size) within the window.
• Connect the clicked signal of the button to the "show_message()" slot using the clicked.connect() method.
• Show the main window using window.show().
• Finally, we start the PyQt application's event loop using app.exec_().

Output:

Flowchart:

Python Code Editor:

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