Qt has no attribute 'AlignCenter' [duplicate]

Question

I am using PyQt5 on Python 3.5.

I want to make a QLabel widget with a centered text. Therefore, I call the setAlignment method with the AlignCenter flag.

Here is an MWE:

import sys
from PyQt5 import QtWidgets, Qt

app = QtWidgets.QApplication(sys.argv)

label = QtWidgets.QLabel()
label.setAlignment(Qt.AlignCenter)

However, I get the following error:

label.setAlignment(Qt.AlignCenter)

AttributeError: module 'PyQt5.Qt' has no attribute 'AlignCenter'

But the Qt.AlignCenter, as well as other alignment flags, are referenced in PyQt's documentation, as well as Qt's documentation.

What am I doing wrong?

Answer 1

The AttributeError that is raised tells that PyQt5.Qt has no attribute called AlignCenter.

This can easily be confirmed in Python's interactive help:

>>> from PyQt5 import Qt
>>> help(Qt)

help will display a bunch of methods, but a quick search of "alignment" will give zero results.

As a matter of fact, the AlignCenter flag does not belong to the PyQt5.Qt module, but to the PyQt5.QtCore.Qt class.

Therefore, changing

label.setAlignment(Qt.AlignCenter)

into

label.setAlignment(QtCore.Qt.AlignCenter)

along with the right import will do the work.

---

The following code shows that this actually works. I had to add some details to the original code to make the centering visible.

import sys
from PyQt5 import QtWidgets, QtCore

app = QtWidgets.QApplication(sys.argv)

label = QtWidgets.QLabel()
label.setGeometry(100, 100, 200, 100)
label.setText("Hello world!")
label.setAlignment(QtCore.Qt.AlignCenter)

label.show()

exit(app.exec_())

With the alignment commented out:

import sys
from PyQt5 import QtWidgets, QtCore

app = QtWidgets.QApplication(sys.argv)

label = QtWidgets.QLabel()
label.setGeometry(100, 100, 200, 100)
label.setText("Hello world!")
# label.setAlignment(QtCore.Qt.AlignCenter)

label.show()

exit(app.exec_())