Force QLineEdit to be a collection of double values

Question

Consider this problem.

I have a QLineEdit in my tool and I should organize a support as follows. The text of LineEdit must contain only double values, separated my comas. F.e. 6.2 , 8, 9.0, 55 I also must validate, that user cannot input any other character but the numbers and comas. Also I should write a method which convert this text into vector. Initially I thought about QRegExp and boost::spirit. But it can be hard using these technique.

Any ideas?

Answer 1

Use next custom Validator.

Header:

#ifndef VALIDATOR_H
#define VALIDATOR_H

#include <QValidator>

class Validator : public QValidator
{
    Q_OBJECT
public:
    explicit Validator(QObject *parent = 0);

signals:

public slots:
public:
    QValidator::State validate(QString & input, int & pos) const;

};

#endif // VALIDATOR_H

Cpp:

#include "validator.h"
#include <QDoubleValidator>
#include <QDebug>
Validator::Validator(QObject *parent) :
    QValidator(parent)
{
}

QValidator::State Validator::validate(QString &input, int &pos) const
{
    qDebug() << input<< pos;
    QDoubleValidator val;
    val.setLocale(QLocale(QLocale::German,QLocale::Germany));
    input.remove(" ");
    QStringList list = input.split(",");
    foreach ( QString var, list) {
        int i = 0;
        if(val.validate(var,i) == QValidator::Invalid)
            return QValidator::Invalid;
    }
    return QValidator::Acceptable;

}

Usage:

ui->lineEdit->setValidator(new Validator);

Explanation about: val.setLocale(QLocale(QLocale::German,QLocale::Germany));

You said that you want use 6.2,... but . and , is different decimal point in different countries. So I wrote example accordingly to your question. German Locale always think that . is a correct point.

But I recommend you to use locale-specific decimal point and use for this Purpose ; as separator instead of coma.

There are mistakes, so try this. Edit(improved):

QValidator::State Validator::validate(QString &input, int &pos) const
{
    qDebug() << input<< pos;
    QRegExpValidator reg(QRegExp("[0-9]+(\\.[0-9]+)?$"));
    input.remove(" ");
    if(input.contains(",,") || input.startsWith(","))
        return QValidator::Invalid;
    QStringList list = input.split(",");
    qDebug()<< list;
    bool isOk = true;
    foreach ( QString var, list) {
        int i = 0;
        if(reg.validate(var,i) == QValidator::Invalid)
            return QValidator::Invalid;
        if(reg.validate(var,i) == QValidator::Intermediate)
            isOk = false;
    }
    if(isOk)
        return QValidator::Acceptable;
    else
        return QValidator::Intermediate;
}