CODEWITHSUNDEEP
c++visual-studioqt
King Henry
King Henry

Reputation: 416

Multiple ranges for QDoubleSpinBoxes in QT

I am building an application that makes use of multiple frequency ranges. I need the user to be able to increase/decrease the values in the QDoubleSpinBox, as well as type in the value. If I increase the value to a number out of one range, I would like the value to jump to the next range (same principle for decreasing a value).

Does a QDoubleSpinBox provide this kind of behavior? I can't seem to find an answer for what I'm looking for. I've tried setting a range using QDoubleValidator, but I don't think it supports multiple ranges (unless I'm missing something). I've also tried using range checks with if statements with the valueChanged() signal that gets emitted, but there must be a simpler way, right?

Here's an example of how I'd like the doubleSpinBox to behave:

Starting Value: 9.75

Range 1: 9.75 - 9.95

Range 2: 10.15 - 10.40

Range 3: 17.2 - 20.4

If value goes above 9.95, jump to 10.15.

If value goes above 10.40, jump to 17.2, etc.

I would also like to have the same behavior when decreasing the value (jumping back down to Range 1 if value drops below 10.15).

I would like to do this without writing multiple if/else if statements if I can avoid it.

Upvotes: 1

Views: 532

Answers (1)

Dimitry Ernot
Dimitry Ernot

Reputation: 6584

Trying to create multiple ranges is not a good solution. You should consider your problem in a different way: you have a single range from 9.75 to 20.40 with forbidden values.

So, if you override method such as QDoubleSpinBox::stepsBy() and QDoubleSpinBox::valueFromText(), you will be able to discard the values outside your ranges:

class Spinbox: public QDoubleSpinBox
{
public:
    Spinbox(): QDoubleSpinBox()
    {
        setRange(9.75, 20.4);
        setSingleStep(0.1);
    }

    virtual void stepBy(int steps) override
    {
        double const newValue = checkValue(value() + (steps * singleStep()));
        setValue(newValue);
    }

    virtual double valueFromText(QString const& text) const override
    {
        qDebug() << text;
        double const newValue = QDoubleSpinBox::valueFromText(text);
        return checkValue(newValue);
    }

    double checkValue(double newValue) const
    {
        qDebug() << newValue << value();
        if (9.95 < newValue && newValue < 10.15)
        {
                if (newValue > value())
                    return 10.15;
                else
                    return 9.95;
        }
        else if (10.4 < newValue && newValue < 17.2)
        {
            if (newValue > value())
                return 17.2;
            else
                return 10.4;
        }
        return newValue;
    }
};

Upvotes: 1

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