Python PyQt5 digital clock widget

Python PyQt Event Handling: Exercise-10 with Solution

Write a Python program to design a PyQt5 digital clock widget that updates the time every second.

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.

QTimer Class: The QTimer class provides repetitive and single-shot timers.

QTime Class: The QTime class provides clock time functions.

QPainter Class: The QPainter class performs low-level painting on widgets and other paint devices.

QFont Class: The QFont class specifies a query for a font used for drawing text.

QColor Class: The QColor class provides colors based on RGB, HSV or CMYK values.

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.

Sample Solution:

Python Code:

import sys
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtCore import QTimer, QTime
from PyQt5.QtGui import QPainter, QFont, QColor
from PyQt5.QtCore import Qt

class DigitalClock(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        self.setGeometry(100, 100, 300, 100)
        self.setWindowTitle("Digital Clock")

        self.timer = QTimer(self)
        self.timer.timeout.connect(self.updateTime)
        self.timer.start(1000)  # Update every 1000 milliseconds (1 second)

        self.current_time = QTime.currentTime()

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.setRenderHint(QPainter.Antialiasing)
        
        # Configure font and color for the digital clock display
        font = QFont('Arial', 30, QFont.Bold)
        painter.setFont(font)
        painter.setPen(QColor(0, 120, 100))  # Black color
        
        # Format and display the current time
        time_str = self.current_time.toString('hh:mm:ss')
        painter.drawText(event.rect(), Qt.AlignCenter, time_str)

    def updateTime(self):
        # Update the current time and repaint the widget
        self.current_time = QTime.currentTime()
        self.repaint()

def main():
    app = QApplication(sys.argv)
    clock = DigitalClock()
    clock.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

Explanation:

In the exercise above -

• Import the necessary modules from PyQt5 for creating the application.
• Create a DigitalClock widget as a subclass of "QWidget".
• In the "initUI()" method, we set up the window's properties and create a QTimer to update the time every second.
• In the "paintEvent()" method, we use QPainter to draw the current time on the widget. We customize the digital clock font and color.
• The updateTime method is called by the timer's timeout signal. It retrieves the current time and triggers a repaint to update the displayed time.
• In the main function, we create an application instance, instantiate the DigitalClock, and start the application event loop.

Output:

Flowchart:

Python Code Editor:

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