How to Create Your First Python GUI Application

Creating your first Python GUI application is great way to get started with GUI programming. this is simple example of How to Create Your First Python GUI Application using PyQt6 library, as you know when you want to build Python GUI Application, you have different libraries and choices, for example we have TKinter, PyQt6, PySide6 and wxPython. in this article we want to create our first Python GUI Application using PyQt6 library.

Introduction to GUI Programming

Graphical User Interface (GUI) programming is an important part of modern software development, because using GUI’s, you can create nice and visually appealing interfaces for your applications. Unlike traditional command-line interfaces (CLI), GUIs allow users to interact with software through graphical elements such as buttons, menus, and windows, making applications more accessible and user-friendly.

Python Developers & GUI Programming

Python developers can greatly benefit from learning GUI programming, because it opens up opportunities to create different types of applications with nice and beautiful user interfaces. This is why GUI programming is valuable for Python developers:

Different Application Development Types: GUI programming allows Python developers to create different types of applications across different domains such as desktop software, web applications, scientific tools, educational software, games and more. With GUI frameworks like PyQt6, Tkinter, PySide6 and wxPython, you have the flexibility to build applications according to your specific needs and target platforms.

Cross-Platform Compatibility: Many GUI frameworks for Python, such as PyQt6 and Tkinter, offer cross-platform compatibility, and using these GUI Frameworks you can write code once and deploy it on multiple platforms without significant modifications. This makes it easier for developers to reach a broader audience and ensures consistent user experiences across different operating systems.
Community Support: Python has large and active community, and it provides a lot of support and resources for GUI programming. Developers can find tutorials, documentation, and open-source projects to help them learn and master GUI programming concepts using Python.

What is PyQt6?

PyQt6 is a set of Python bindings for Qt, Qt is a cross-platform application framework. Qt allows you to create applications with a native look and feel for different operating systems, including Windows, macOS, Linux, and mobile platforms using C++ programming language.

PyQt6 enables Python developers to access Qt’s functionality and create graphical user interfaces (GUIs) for their applications using Python. It provides modules and classes that allows you to create windows, dialogs, buttons, menus, and other GUI components, also you can handle events and signals.

PyQt6 Vs PyQt5?

PyQt6 is the latest version of PyQt, It offers support for Qt 6, the newest major version of the Qt framework. Also it provides enhancements and improvements over previous versions, including better compatibility with Qt 6 and Python 3.9. on the other hand PyQt5 is the previous version.

How to Install PyQt6?

You can use pip for the installation of PyQt6, open your command prompt or terminal and write this command.

pip install PyQt6

1	pip install PyQt6

To Create Your First Python GUI Application with Python, you need to follow these steps:

Import required classes from Python PyQt6 library

import sys
from PyQt6.QtWidgets import QApplication, QLabel, QMainWindow

1 2	import sys from PyQt6.QtWidgets import QApplication, QLabel, QMainWindow

Create QMainWindow instance

window = QMainWindow()
window.setWindowTitle("My First GUI App")

1 2	window = QMainWindow() window.setWindowTitle("My First GUI App")

Create QLabel instance

label = QLabel(window)
label.setText("Welcome to codeloop.org")

1 2	label = QLabel(window) label.setText("Welcome to codeloop.org")

Set label position within the main window

label.move(50, 50)

1	label.move(50, 50)

Show the main window

window.show()

1	window.show()

Execute the application’s event loop

 sys.exit(app.exec())

1	sys.exit(app.exec())

This is the complete code

import sys
from PyQt6.QtWidgets import QApplication, QLabel, QMainWindow

def main():
    # Create QApplication instance
    app = QApplication(sys.argv)

    # Create QMainWindow instance
    window = QMainWindow()
    window.setWindowTitle("My First GUI App")

    # Create QLabel instance
    label = QLabel(window)
    label.setText("Codeloop.org")

    # Set label position within the main window
    label.move(50, 50)

    # Show the main window
    window.show()

    # Execute the application's event loop
    sys.exit(app.exec())

if __name__ == "__main__":
    main()

import sys

from PyQt6.QtWidgets import QApplication, QLabel, QMainWindow

def main():

# Create QApplication instance

app = QApplication(sys.argv)

# Create QMainWindow instance

window = QMainWindow()

window.setWindowTitle("My First GUI App")

# Create QLabel instance

label = QLabel(window)

label.setText("Codeloop.org")

# Set label position within the main window

label.move(50, 50)

# Show the main window

window.show()

# Execute the application's event loop

sys.exit(app.exec())

if __name__ == "__main__":

main()

This code creates a simple GUI application with a window displaying a label saying “Codeloop.org”.

Run the code and this will be the result

How to Create Your First Python GUI Application

PyQt5 QMessageBox Practical Example

Create More Complex GUIs with Python – Build PyQt6 Calculator

Now we have created a basic Python GUI using PyQt6, now let’s create complex Python GUI, and this time we want to create a calculator with Python PyQt6.

How to Build Calculator with Python Code Example

import sys
from PyQt6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QGridLayout, QPushButton, QLineEdit
from PyQt6.QtGui import QIcon

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

        # Set window title
        self.setWindowTitle("Codeloop - Calculator")

        # Set window icon
        self.setWindowIcon(QIcon('python.png'))

        # Create central widget
        self.central_widget = QWidget()

        # Set central widget
        self.setCentralWidget(self.central_widget)

        # Create vertical layout for central widget
        self.layout = QVBoxLayout(self.central_widget)

        # Create line edit widget for display
        self.display = QLineEdit()

        # Add display widget to layout
        self.layout.addWidget(self.display)

        # Create grid layout for buttons
        buttons_layout = QGridLayout()

        # Define buttons with their text and position in the grid
        buttons = [
            ("7", 0, 0), ("8", 0, 1), ("9", 0, 2), ("/", 0, 3),
            ("4", 1, 0), ("5", 1, 1), ("6", 1, 2), ("*", 1, 3),
            ("1", 2, 0), ("2", 2, 1), ("3", 2, 2), ("-", 2, 3),
            ("0", 3, 0), (".", 3, 1), ("=", 3, 2), ("+", 3, 3)
        ]

        # Create buttons and connect their click
        # event to on_button_click method
        for text, row, col in buttons:
            button = QPushButton(text)
            buttons_layout.addWidget(button, row, col)
            button.clicked.connect(self.on_button_click)

        # Add buttons layout to central widget layout
        self.layout.addLayout(buttons_layout)

    def on_button_click(self):

        # Get the button that triggered the event
        button = self.sender()
        if button:

            # Get the text of the button
            text = button.text()
            if text == "=":

                # Get the expression from the display
                expression = self.display.text()
                try:

                    # Evaluate the expression
                    result = eval(expression)

                    # Display the result
                    self.display.setText(str(result))
                except Exception as e:

                    # Display error message if evaluation fails
                    self.display.setText("Error")
            else:

                # Get current text from display
                current_text = self.display.text()

                # Append button text to display text
                self.display.setText(current_text + text)


def main():
    # Create application instance
    app = QApplication(sys.argv)

    # Create main window instance
    window = CalculatorApp()

    # Show main window
    window.show()

    # Execute application event loop
    sys.exit(app.exec())


if __name__ == "__main__":
    main()

import sys

from PyQt6.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QGridLayout, QPushButton, QLineEdit

from PyQt6.QtGui import QIcon

class CalculatorApp(QMainWindow):

def __init__(self):

super().__init__()

# Set window title

self.setWindowTitle("Codeloop - Calculator")

# Set window icon

self.setWindowIcon(QIcon('python.png'))

# Create central widget

self.central_widget = QWidget()

# Set central widget

self.setCentralWidget(self.central_widget)

# Create vertical layout for central widget

self.layout = QVBoxLayout(self.central_widget)

# Create line edit widget for display

self.display = QLineEdit()

# Add display widget to layout

self.layout.addWidget(self.display)

# Create grid layout for buttons

buttons_layout = QGridLayout()

# Define buttons with their text and position in the grid

buttons = [

("7", 0, 0), ("8", 0, 1), ("9", 0, 2), ("/", 0, 3),

("4", 1, 0), ("5", 1, 1), ("6", 1, 2), ("*", 1, 3),

("1", 2, 0), ("2", 2, 1), ("3", 2, 2), ("-", 2, 3),

("0", 3, 0), (".", 3, 1), ("=", 3, 2), ("+", 3, 3)

]

# Create buttons and connect their click

# event to on_button_click method

for text, row, col in buttons:

button = QPushButton(text)

buttons_layout.addWidget(button, row, col)

button.clicked.connect(self.on_button_click)

# Add buttons layout to central widget layout

self.layout.addLayout(buttons_layout)

def on_button_click(self):

# Get the button that triggered the event

button = self.sender()

if button:

# Get the text of the button

text = button.text()

if text == "=":

# Get the expression from the display

expression = self.display.text()

try:

# Evaluate the expression

result = eval(expression)

# Display the result

self.display.setText(str(result))

except Exception as e:

# Display error message if evaluation fails

self.display.setText("Error")

else:

# Get current text from display

current_text = self.display.text()

# Append button text to display text

self.display.setText(current_text + text)

def main():

# Create application instance

app = QApplication(sys.argv)

# Create main window instance

window = CalculatorApp()

# Show main window

window.show()

# Execute application event loop

sys.exit(app.exec())

if __name__ == "__main__":

main()

In this example, we have create a simple Python GUI calculator application using PyQt6. this application has a main window with a text input field for displaying the calculation result and a grid of buttons for inputting numbers and operations.

CalculatorApp class inherits from QMainWindow and sets up the main window with a central widget and layout. The calculator display is implemented using a QLineEdit widget, and the buttons are arranged using a QGridLayout.

Each button in the grid corresponds to a digit, arithmetic operation or equals sign. By clicking a button, we appends its text to the display, and it allows users to input numbers and operations. When the equals button is clicked, the expression entered by the user is evaluated using Python eval() function, and the result is displayed in the calculator’s display field.

The main() function creates an instance of the CalculatorApp class, and it shows the main window, and starts the application event loop.

This example demonstrates how to create more complex GUI application with Python & PyQt6, because we have integrated multiple widgets, and also we are handling user interactions to perform calculations. Users can use this calculator to perform basic arithmetic operations inside the GUI environment.