QSpinBox Class

If using prefix(), suffix(), and specialValueText() don't provide enough control, you subclass QSpinBox and reimplement valueFromText() and textFromValue(). For example, here's the code for a custom spin box that allows the user to enter icon sizes (e.g., "32 x 32"):

int IconSizeSpinBox::valueFromText(const QString &text) const
{
    static const QRegularExpression regExp(tr("(\\d+)(\\s*[xx]\\s*\\d+)?"));
    Q_ASSERT(regExp.isValid());

    const QRegularExpressionMatch match = regExp.match(text);
    if (match.isValid())
        return match.captured(1).toInt();
    return 0;
}

QString IconSizeSpinBox::textFromValue(int value) const
{
    return tr("%1 x %1").arg(value);
}

See the Icons example for the full source code.

See also QDoubleSpinBox, QDateTimeEdit, QSlider, Spin Boxes Example

This property holds the text of the spin box excluding any prefix, suffix, or leading or trailing whitespace.

Access functions:

• cleanText() const

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This property holds the base used to display the value of the spin box

The default displayIntegerBase value is 10.

This property was introduced in Qt 5.2.

Access functions:

• int displayIntegerBase() const

• void setDisplayIntegerBase(int base)

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This property holds the maximum value of the spin box

When setting this property the minimum is adjusted if necessary, to ensure that the range remains valid.

The default maximum value is 99.

Access functions:

• int maximum() const

• void setMaximum(int max)

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This property holds the minimum value of the spin box

When setting this property the maximum is adjusted if necessary to ensure that the range remains valid.

The default minimum value is 0.

Access functions:

• int minimum() const

• void setMinimum(int min)

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This property holds the spin box's prefix

The prefix is prepended to the start of the displayed value. Typical use is to display a unit of measurement or a currency symbol. For example:

sb->setPrefix("$");

To turn off the prefix display, set this property to an empty string. The default is no prefix. The prefix is not displayed when value() == minimum() and specialValueText() is set.

If no prefix is set, prefix() returns an empty string.

Access functions:

• prefix() const

• void setPrefix(const &prefix)

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This property holds the step value

When the user uses the arrows to change the spin box's value the value will be incremented/decremented by the amount of the singleStep. The default value is 1. Setting a singleStep value of less than 0 does nothing.

Access functions:

• int singleStep() const

• void setSingleStep(int val)

This property holds the step type.

The step type can be single step or adaptive decimal step.

Access functions:

• stepType() const

• void setStepType( stepType)

This property holds the suffix of the spin box

The suffix is appended to the end of the displayed value. Typical use is to display a unit of measurement or a currency symbol. For example:

sb->setSuffix(" km");

To turn off the suffix display, set this property to an empty string. The default is no suffix. The suffix is not displayed for the minimum() if specialValueText() is set.

If no suffix is set, suffix() returns an empty string.

Access functions:

• suffix() const

• void setSuffix(const &suffix)

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This property holds the value of the spin box

setValue() will emit valueChanged() if the new value is different from the old one. The value property has a second notifier signal which includes the spin box's prefix and suffix.

Access functions:

• int value() const

• void setValue(int val)

Notifier signal:

• void valueChanged(int i)

Constructs a spin box with 0 as minimum value and 99 as maximum value, a step value of 1. The value is initially set to 0. It is parented to parent.

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Destructor.

Reimplements: QAbstractSpinBox::event(QEvent *event).

Reimplements: QAbstractSpinBox::fixup(QString &input) const.

Convenience function to set the minimum, and maximum values with a single function call.

setRange(minimum, maximum);

is equivalent to:

setMinimum(minimum);
setMaximum(maximum);

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Sets the step type for the spin box to stepType, which is single step or adaptive decimal step.

Adaptive decimal step means that the step size will continuously be adjusted to one power of ten below the current value. So when the value is 1100, the step is set to 100, so stepping up once increases it to 1200. For 1200 stepping up takes it to 1300. For negative values, stepping down from -1100 goes to -1200.

Step direction is taken into account to handle edges cases, so that stepping down from 100 takes the value to 99 instead of 90. Thus a step up followed by a step down – or vice versa – always lands on the starting value; 99 -> 100 -> 99.

Setting this will cause the spin box to disregard the value of singleStep, although it is preserved so that singleStep comes into effect if adaptive decimal step is later turned off.

This function was introduced in Qt 5.12.

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This signal is emitted whenever the spin box's text is changed. The new text is passed in text with prefix() and suffix().

This function was introduced in Qt 5.14.

This virtual function is used by the spin box whenever it needs to display the given value. The default implementation returns a string containing value printed in the standard way using QWidget::locale().toString(), but with the thousand separator removed unless setGroupSeparatorShown() is set. Reimplementations may return anything. (See the example in the detailed description.)

Note: QSpinBox does not call this function for specialValueText() and that neither prefix() nor suffix() should be included in the return value.

If you reimplement this, you may also need to reimplement valueFromText() and validate()

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Reimplements: QAbstractSpinBox::validate(QString &input, int &pos) const.

This signal is emitted whenever the spin box's value is changed. The new value's integer value is passed in i.

This virtual function is used by the spin box whenever it needs to interpret text entered by the user as a value.

Subclasses that need to display spin box values in a non-numeric way need to reimplement this function.

Note: QSpinBox handles specialValueText() separately; this function is only concerned with the other values.

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