Qt for Python Quick start

Requirements

Before you can install Qt for Python, first you must install the following software:

  • Python 2.7 or 3.5+ (we recommend 3.5+),

  • We recommend using a virtual environment, such as venv or virtualenv

Creating and activating an environment

You can do this by running the following on a terminal:

$ python -m venv env/       # Your binary is maybe called 'python3'
$ source env/bin/activate   # for Linux and macOS
$ env\Scripts\activate.bat  # for Windows

Installation

Now you are ready to install the Qt for Python packages using pip. From the terminal, run the following command:

# For the latest version on PyPi
pip install PySide2

# For a specific version
pip install PySide2==5.15.0

or:

pip install --index-url=http://download.qt.io/snapshots/ci/pyside/5.15/latest pyside2 --trusted-host download.qt.io

Test your Installation

Now that you have Qt for Python installed, you can test your setup by running the following Python constructs to print version information:

import PySide2.QtCore

# Prints PySide2 version
print(PySide2.__version__)

# Prints the Qt version used to compile PySide2
print(PySide2.QtCore.__version__)

Create a Simple Application

Your Qt for Python setup is ready. You can explore it further by developing a simple application that prints “Hello World” in several languages. The following instructions will guide you through the development process:

  1. Create a new file named hello_world.py, and add the following imports to it.:

    import sys
import random
from PySide2 import QtCore, QtWidgets, QtGui

The PySide2 Python module provides access to the Qt APIs as its submodule. In this case, you are importing the QtCore, QtWidgets, and QtGui submodules.

  1. Define a class named MyWidget, which extends QWidget and includes a QPushButton and QLabel.:

    class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()

        self.hello = ["Hallo Welt", "Hei maailma", "Hola Mundo", "Привет мир"]

        self.button = QtWidgets.QPushButton("Click me!")
        self.text = QtWidgets.QLabel("Hello World",
                                     alignment=QtCore.Qt.AlignCenter)

        self.layout = QtWidgets.QVBoxLayout()
        self.layout.addWidget(self.text)
        self.layout.addWidget(self.button)
        self.setLayout(self.layout)

        self.button.clicked.connect(self.magic)

    @QtCore.Slot()
    def magic(self):
        self.text.setText(random.choice(self.hello))

The MyWidget class has the magic member function that randomly chooses an item from the hello list. When you click the button, the magic function is called.

  1. Now, add a main function where you instantiate MyWidget and show it.:

    if __name__ == "__main__":
    app = QtWidgets.QApplication([])

    widget = MyWidget()
    widget.resize(800, 600)
    widget.show()

    sys.exit(app.exec_())

Run your example. Try clicking the button at the bottom to see which greeting you get.

Hello World application