Python qt: bindings

Qt is written in C++. bindings make it possible to abstract/expose C++ objects as native python objects.

bindings

Different bindings may be licensed differently, and because of differences in their abstractions - they may not behave consistently. It would be prudent to test against multiple sets bindings, I have personally experienced breaking changes between different bindings to the same version of Qt.

bindings	Qt version	license	project stuatus
PySide	Qt4	LGPL	completed, no longer receiving fixes
PyQt4	Qt4
PySide2	Qt5	LGPL	alpha
PyQt5	Qt5

PySide2

Compiling PySide2: https://fredrikaverpil.github.io/2016/08/17/compiling-pyside2/

abstractions

There are also a handful of libraries that abstract over the various python bindings for qt. These are especially useful if you find yourself needing to support multiple versions of Qt with the same codebase.

project		PySide	PySide2	PyQt4	PyQt5
Qt.py		yes	yes	yes	yes
qtpy		yes	waiting until beta	yes	yes

Qt.py

environment variable	examples	description
QT_PREFERRED_BINDING	PySide, PySide2, PyQt4, PyQt5	if defined, use this binding.

import Qt
from Qt import QtWidgets

qtpy

environment variable	examples	description
QT_API	pyside, pyqt4, pyqt5	if defined, use this binding.

from qtpy import QtWidgets