Allow entry in QLineEdit only within range of QDoubleValidator

Question

I have a set of QLineEdits that are supposed to accept double values within a certain range, (e.g., -15 to 15).

I have something along these lines when

Answer 1

I tried the excellent class above and it still needs a couple edits. The decimal point search was reducing the range specified by "top" because it returned a "-1" when there is no decimal point. I added a conditional statement that fixes that.

Also, it still needs to be tweaked for the case where the user tries to delete the decimal point and the resulting value is larger than the range. Right now it just prohibits that behavior rather than changing it to the maximum value which seems more intuitive to me.

class MyValidator : public QDoubleValidator
{
    public:
    MyValidator(double bottom, double top, int decimals, QObject * parent) :
    QDoubleValidator(bottom, top, decimals, parent)
    {
    }

    QValidator::State validate(QString &s, int &i) const
    {
        if (s.isEmpty() || s == "-") {
            return QValidator::Intermediate;
        }

        QLocale locale;

        QChar decimalPoint = locale.decimalPoint();
        int charsAfterPoint = s.length() - s.indexOf(decimalPoint) -1;

        if (charsAfterPoint > decimals() && s.indexOf(decimalPoint) != -1) {
            return QValidator::Invalid;
        }

        bool ok;
        double d = locale.toDouble(s, &ok);

        if (ok && d >= bottom() && d <= top()) {
            return QValidator::Acceptable;
        } else {
            return QValidator::Invalid;
        }
    }
};