How to restrict user input in QLineEdit in pyqt

Question

I have a QLineEdit and i want to restrict QLineEdit to accept only integers. It should work like inputmask. But I dont want to use inputmask, because if user clicks on QLineEdit cursor will be at the position where mouse was clicked. and user need to navigate to 0 position and type what eve he wants.

Is there any alternate for this.

score 55 · Answer 1 · edited Aug 11 '22 at 07:44

55

you can use QValidator. It works like:

# from PyQt5.QtGui import QIntValidator
# from PyQt6.QtGui import QIntValidator

# allow only integers
onlyInt = QIntValidator()
onlyInt.setRange(0, 4)
lineEdit.setValidator(onlyInt)

edited Aug 11 '22 at 07:44

DomTomCat

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answered Jun 25 '17 at 20:02

Fe3back

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This is the appropriate way to do it. Using validator. – Enkum Nov 12 '18 at 07:51
how would I use this in combination with a qlineedit() ? – Ben Oct 06 '22 at 12:59
1

@Ben lineEdit is a QLineEdit() widget, so before that line assume this: lineEdit = QLineEdit() ... – alielbashir Nov 07 '22 at 19:52

scottydelta · Answer 2 · 2013-04-05T15:16:22.393

9

you can use exception handling for validating this:

number = self.ui.number_lineEdit.text()
try:
    number = int(number)
except Exception:
    QtGui.QMessageBox.about(self, 'Error','Input can only be a number')
    pass

you can also use validators to validate input strings.

edited Apr 05 '13 at 15:16

answered Apr 05 '13 at 15:10

scottydelta

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i heard about `validators`, but did not get find a correct example on how to set it to `QLineEdit`. Mean while i will try your approch. I think Validators are the good options for professional approach. – Rao Apr 06 '13 at 11:42
1

try learning from this question here http://stackoverflow.com/questions/5770441/checking-qvalidators-state – scottydelta Apr 07 '13 at 02:49
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A good exemple of how to use validators is here: http://snorf.net/blog/2014/08/09/using-qvalidator-in-pyqt4-to-validate-user-input/ – maurobio Apr 18 '15 at 14:06
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@maurobio - linkupdate: https://snorfalorpagus.net/blog/2014/08/09/validating-user-input-in-pyqt4-using-qvalidator – ZF007 Nov 26 '17 at 12:38

How to restrict user input in QLineEdit in pyqt

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