Python PyQt keyboard shortcut example

Python PyQt Connecting Signals to Slots: Exercise-15 with Solution

Write a Python program that makes an application listen to keyboard shortcuts, like pressing a specific key combination. When you press that key combination, a message appears. Use the 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.

QLabel Class: The QLabel widget provides a text or image display.

QKeySequence Class: The QKeySequence class encapsulates a key sequence as used by shortcuts.

Qt module: PyQt5 is a set of Python bindings for the Qt application framework. It allows us to use Qt, a popular C++ framework, to create graphical user interfaces (GUIs) in Python.

QShortcut Class: The QShortcut class is used to create keyboard shortcuts.

Sample Solution:

Python Code:

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel
from PyQt5.QtGui import QKeySequence
from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QShortcut

class ShortcutApp(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle("Shortcut Example")
        self.setGeometry(100, 100, 400, 200)  # (x, y, width, height)

        # Create a label to display messages
        self.message_label = QLabel("Press Ctrl+M to show a message", self)
        self.message_label.setAlignment(Qt.AlignmentFlag.AlignCenter)

        self.setCentralWidget(self.message_label)

        # Create a keyboard shortcut Ctrl+M
        shortcut = QKeySequence(Qt.CTRL + Qt.Key_M)
        self.shortcut = QShortcut(shortcut, self)
        self.shortcut.activated.connect(self.show_message)

    def show_message(self):
        # Display a message when the shortcut is activated
        self.message_label.setText("You pressed Ctrl+M!")

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

if __name__ == "__main__":
    main()

Explanation:

In the exercise above -

• Import the necessary modules from PyQt5.
• Create a custom "QMainWindow" class named "ShortcutApp" that builds the main application window.
• "QLabel" (self.message_label) displays messages inside the window.
• Set up a keyboard shortcut (Ctrl+M) using QKeySequence.
• Connect the shortcut's activated signal to a slot function (self.show_message) that displays a message.
• Create a QShortcut object named self.shortcut and set its shortcut to Ctrl+S.
• In the "show_message()" slot function, we change the label's text to "You pressed Ctrl+M!" when the shortcut is activated.
• In the main function, we create the PyQt application, instantiate the ShortcutApp class, and show the main window.

Output:

Flowchart:

Python Code Editor:

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