CODEWITHSUNDEEP
regexqt
oggmonster
oggmonster

Reputation: 4872

Qt inputMask and QValidator for QLineEdit (Hex validation)

I have a QLineEdit that a user is able to give input to using a keyboard. The line edit must only accept hexadecimal characters. The line edit must automatically put a delimiter character between every set of 2 hex characters The last delimiter character should be automatically removed when the user deletes the last hex characters.

I have tried this: ui->mTextEdit->setInputMask("Hh,hh,hh,hh,hh");

But unfortunately all of the commas are displayed when there is no text, and you have to know how many sets of hex numbers you want in advance (which I don't know/can't restrict).

Could I use a QValidator to do this for me?

Upvotes: 1

Views: 7146

Answers (1)

ayoy
ayoy

Reputation: 3835

You can use a custom subclass of QValidator, with validate() e.g. like this:

QValidator::State HexValidator::validate(QString &input, int &pos) const
{
    // remove trailing comma
    if (input.endsWith(',')) {
        input.chop(1);
    }

    // insert comma when third hex in a row was entered
    QRegExp rxThreeHexAtTheEnd("(?:[0-9a-fA-F]{2},)*[0-9a-fA-F]{3}");
    if (rxThreeHexAtTheEnd.exactMatch(input)) {
        input.insert(input.length()-1, ',');
        pos = input.length();
    }

    // match against needed regexp
    QRegExp rx("(?:[0-9a-fA-F]{2},)*[0-9a-fA-F]{0,2}");
    if (rx.exactMatch(input)) {
        return QValidator::Acceptable;
    }
    return QValidator::Invalid;
}

Upvotes: 4

Related Questions