QValidator: no spaces

Dummie1138

Hi. I am trying to create a validator for a QLineEdit that does not accept spaces in it's input. To do this, I have the following validator in a QLineEdit.

nameInput = new QLineEdit;
nameInput->setValidator(new QRegExpValidator( QRegExp("^\S*$"), this ));

I am, however, unable to edit anything in the QLineEdit after I have set up the validator. Specifically, I am unable to add or delete any characters in the QLineEdit while it is active. I am unsure why this is the case as I believe my Regex syntax to be accurate.

The full relevant code:

inputBox = new QDialog(this);
 //Set size of QDialog.
 inputBox->resize(450, 160);
 inputBox->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
 inputBox->setStyleSheet("font: 20px; color: navy; border: none; outline: none;");
 inputBox->setWindowFlag(Qt::WindowContextHelpButtonHint, false);
 QGridLayout *gridLayout = new QGridLayout(this);
 inputBox->setLayout(gridLayout);
 
 //QLabel
 QLabel *boxText = new QLabel(this);
 boxText->setText("Update test presets:");
 boxText->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Minimum);
 boxText->setAlignment(Qt::AlignCenter);
 gridLayout->addWidget(boxText, 0, 0, 1, 2, Qt::AlignCenter);
 
 //Add a QLineEdit, problem code is here
 nameInput = new QLineEdit;
 nameInput->setText(configName);
 QRegularExpressionValidator *re = new QRegularExpressionValidator;
 nameInput->setValidator(new QRegExpValidator( QRegExp("/^\S/"), this ));
 gridLayout->addWidget(nameInput, 1, 1);
 
 //QLabel
 QLabel *nameText = new QLabel(this);
 nameText->setText("Preset name:");
 nameText->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Minimum);
 nameText->setAlignment(Qt::AlignLeft);
 gridLayout->addWidget(nameText, 1, 0);
 
 //Add a QLineEdit
 startTempInput = new QLineEdit;
 startTempInput->setText(QString::number(startTemp));
 startTempInput->setValidator(new QIntValidator(0, 86, this));
 gridLayout->addWidget(startTempInput, 2, 1);
 
 //QLabel
 QLabel *startTempText = new QLabel(this);
 startTempText->setText("Start temp:");
 startTempText->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Minimum);
 startTempText->setAlignment(Qt::AlignLeft);
 gridLayout->addWidget(startTempText, 2, 0);
 
 //Add a QLineEdit
 expFlashptInput = new QLineEdit;
 expFlashptInput->setText(QString::number(expFlashpt));
 expFlashptInput->setValidator(new QIntValidator(0, 86, this));
 gridLayout->addWidget(expFlashptInput, 3, 1);
 
 //QLabel
 QLabel *expFlashptText = new QLabel(this);
 expFlashptText->setText("Expected flashpt:");
 expFlashptText->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Minimum);
 expFlashptText->setAlignment(Qt::AlignLeft);
 gridLayout->addWidget(expFlashptText, 3, 0);
 
 //Add a QDialogButtonBox
 QDialogButtonBox *boxButton = new QDialogButtonBox(QDialogButtonBox::Ok, this);
 boxButton->setStyleSheet("QPushButton {border: 2px solid #8f8f91;border-radius: 9px;background-color: QLinearGradient(x1: 0, y1: 0, x2: 0, y2: 1,stop: 0 #f6f7fa, stop: 1 #dadbde);font: 25px;outline: none;}"
 "QPushButton:pressed {background-color: QLinearGradient(x1: 0, y1: 0, x2: 0, y2: 1,stop: 0 #dadbde, stop: 1 #f6f7fa) }");
 boxButton->findChild<QPushButton *>()->setMinimumSize(80, 50);
 gridLayout->addWidget(boxButton, 4, 0, 1, 2, Qt::AlignCenter); //Fix magic numbers
 setTestConfig_isNew = false;
 //Read information
 connect(boxButton, SIGNAL(accepted()), this, SLOT(setTestConfig()));
 inputBox->exec();

Please let me know if more information is required to solve this issue.

JonB

@Dummie1138
Good on the backslashes, but no you are going too far. The attempt you had is actually close. It would need to be

"^\\S*$"

But if that doesn't work the link I referenced says QRegExpValidator already assumes ^...$ around your expression, i.e. complete match. So your ^/$ may be being taken literally. Try just

"\\S*"

?

JoeCFD

@Dummie1138 try "^[^\s]+$"

? Offline

I see a difference between your two code blocks

@Dummie1138 said in QValidator: no spaces:

nameInput->setValidator(new QRegExpValidator( QRegExp("^\S*$"), this ));

and

nameInput->setValidator(new QRegExpValidator( QRegExp("/^\S/"), this ));

In one case you use leading and trailing slashes, in the other you don't. your "full relevant code" is wrong.

JonB

@Dummie1138 said in QValidator: no spaces:

QRegularExpressionValidator *re = new QRegularExpressionValidator;
nameInput->setValidator(new QRegExpValidator( QRegExp("/^\S/"), this ));

Why do you create a QRegularExpressionValidator and then introduce QRegExpValidator/QRegExp? The latter should not be used any longer.

How do you think the C++ literal string "/^\S/" is treated/resolves to?

Dummie1138

@JonB QRegularExpressionValidator is there as a piece of commented code. As for QRegExpValidator/QRegExp, what's wrong with it?

My understanding of "/^\S/" is that \S indicates a whitespace, and ^ indicates that it should not be the starter character.

JonB

@Dummie1138 said in QValidator: no spaces:

what's wrong with it?

Like I said "The latter should not be used any longer." It was deprecated at Qt 5.x, removed in Qt6. Since QRegularExpression does the same and is better there's not much to discuss.

@Dummie1138 said in QValidator: no spaces:

My understanding of "/^\S/" is that \S indicates a whitespace

Forget about regular expressions. Review the rules on \ characters in C/C++ literal strings.

Then regular expression \S does not match whitespace, it matches non-whitespace. If QRegExp supports this at all, I don't know.

and ^ indicates that it should not be the starter character.

^ indicates the start of the string match, what follows it must be the first character, not "not be the starter character". However, see https://doc.qt.io/qt-5/qregexpvalidator.html#details about ^/$, those may be part of your problem, I don't know for sure since it's QRegExp stuff.

Dummie1138

@JonB Oh yeah crap. Though I can't recall anything about \S as a special backslash character, I assume in order for C++ to be able to read the backslash we will require "\" instead of "".

In that case, would the exclusion character be [^ and ]? I assume something akin to [^\\S] would be more appropriate.

JonB

@Dummie1138
Good on the backslashes, but no you are going too far. The attempt you had is actually close. It would need to be

"^\\S*$"

But if that doesn't work the link I referenced says QRegExpValidator already assumes ^...$ around your expression, i.e. complete match. So your ^/$ may be being taken literally. Try just

"\\S*"

?