Save Qt State In Json

01 Oct 2019

How to convert a QByteArray to unicode to be able to save it in a text file using Python.

When working with Qt it is possible to save and restore some widget state using saveState and restoreState method. Calling saveState return a QByteArray. How can I write this QByteArray to a text file and reload it after ?

Convert QByteArray to Unicode

import json

from PyQt5 import QtWidgets, QtCore

# create a widget to save the state
my_window = QtWidgets.QMainWindow()

qbyte_array = my_window.saveState()

codec = QtCore.QTextCodec.codecForName("UTF-16")
unicode_str = codec.toUnicode(qbyte_array)

to_write = json.dumps({'widget_sate': unicode_str}, indent=4)

Convert Unicode to QByteArray

text_encoder = codec.makeEncoder(QtCore.QTextCodec.IgnoreHeader)
qbyte_array = text_encoder.fromUnicode(unicode_str)
my_window.restoreState(qbyte_array)