QRegExpValidator maximum value

Question

I would like to use QRegExpValidator in order to force user to: - type in values only from a certain range (double type), - the double type should be typed in using dot not coma - no other formats are allowed

So far I have:

QRegExpValidator* rxv = new QRegExpValidator(QRegExp("[-+]?[0-9]*\\.?[0-9]+([eE][-+]?[0-9]+)?"), this);

This validator forces user to type in only double values with dot. I Dont know however, how to prevent user from typing in values out of range (for example range would be from 0 to 100.0). I Would aprichiate all help.

Answer 1

You can write your own validator, derived from QValidator. All you need is to implement virtual State validate(QString &input, int &pos) const = 0.

UPDATE

Example:

MyValidator.h:

class MyValidator : public QValidator
{
    Q_OBJECT
public:
    MyValidator(double min, double max, QObject *parent = 0);

    State validate(QString &input, int &pos) const;

private:
    QRegExp mRexp;
    double mMin;
    double mMax;
};

MyValidator.cpp:

MyValidator::MyValidator(double min, double max, QObject *parent) :
    QValidator(parent)
  , mRexp("[-+]?[0-9]*\\.?[0-9]+([eE][-+]?[0-9]+)?")
  , mMin(min)
  , mMax(max)
{}

QValidator::State MyValidator::validate(QString &input, int &pos) const
{
    if (input.isEmpty())
        return Acceptable;
    if (!mRexp.exactMatch(input))
        return Invalid;
    const double val = input.toDouble();
    if (mMin <= val && val <= mMax)
        return Acceptable;
    return Intermediate;
}