PyCon PL 2015: Piotr Maliński presents “Creating Desktop Applications with PyQt”

PyCon PL 2015 was an annual Python conference held in Poland, and one of the talks that took place during this event was by Piotr Maliński titled "Aplikacje desktopowe z PyQt" or "Desktop applications with PyQt". In this tutorial, we will explore the key points of his talk and provide a detailed guide on how to develop desktop applications using PyQt.

PyQt is a set of Python bindings for the Qt application framework, which is widely used for developing cross-platform applications with a native look and feel. It provides tools for creating graphical user interfaces (GUIs) and handling events, as well as other features such as networking, file I/O, and multimedia support.

During his talk, Piotr Maliński covered various topics related to developing desktop applications with PyQt, including:

1. Introduction to PyQt: He started by introducing PyQt and its key features, such as the Qt Designer tool for designing GUI layouts visually, and the PyQt modules for creating custom widgets, handling events, and managing application state.

2. Creating a simple application: Maliński demonstrated how to create a basic desktop application using PyQt, with a main window containing a label, a button, and a text input field. He explained how to use layout managers (such as QVBoxLayout and QHBoxLayout) to arrange the widgets in the window, and how to connect signals and slots to handle user interactions.

3. Handling events: He also discussed how to handle events in PyQt, such as button clicks, key presses, and mouse movements. He showed how to use the event system to respond to user actions and update the application’s state accordingly.

4. Styling and theming: Maliński talked about how to style and theme PyQt applications using Qt’s style sheets, which allow you to customize the appearance of widgets, colors, fonts, and other visual elements. He demonstrated how to create custom styles and apply them to different parts of the application.

5. Advanced features: Finally, he concluded by showcasing some advanced features of PyQt, such as using the QThread class for parallel processing, integrating with external libraries and APIs, and packaging the application for distribution on different platforms.

In order to follow along with this tutorial and start developing desktop applications with PyQt, you will need to have PyQt installed on your system. You can install it using the following command:

pip install PyQt5

Once you have PyQt installed, you can start creating your own desktop applications by following these steps:

1. Create a new Python script and import the necessary PyQt modules:

   from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QPushButton, QVBoxLayout, QWidget

2. Initialize the PyQt application and create a main window:

   app = QApplication([])
   window = QMainWindow()
   window.setWindowTitle('My PyQt App')

3. Create widgets and layout managers for the main window:

   label = QLabel('Hello, PyQt!')
   button = QPushButton('Click me')
   layout = QVBoxLayout()
   layout.addWidget(label)
   layout.addWidget(button)

4. Set the layout for the main window and connect signals and slots:

   widget = QWidget()
   widget.setLayout(layout)
   window.setCentralWidget(widget)
   button.clicked.connect(lambda: label.setText('Button clicked!'))

5. Show the main window and start the PyQt event loop:

   window.show()
   app.exec_()

By following these steps, you can create a simple desktop application with PyQt and get started with building more complex and feature-rich applications. Feel free to explore the PyQt documentation and examples to learn more about its capabilities and find inspiration for your own projects. Happy coding!