QDoubleSpinBox Class

Member Function Documentation

QDoubleSpinBox::QDoubleSpinBox(QWidget *parent = nullptr)

Constructs a spin box with 0.0 as minimum value and 99.99 as maximum value, a step value of 1.0 and a precision of 2 decimal places. The value is initially set to 0.00. The spin box has the given parent.

See also setMinimum(), setMaximum(), and setSingleStep().

[signal] void QDoubleSpinBox::textChanged(const QString &text)

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.

[signal] void QDoubleSpinBox::valueChanged(double d)

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

Note: Notifier signal for property value.

Note: Signal valueChanged is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:

 connect(doubleSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged),
     [=](double d){ /* ... */ });

[virtual] QDoubleSpinBox::~QDoubleSpinBox()

Destructor.

[override virtual] void QDoubleSpinBox::fixup(QString &input) const

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

void QDoubleSpinBox::setRange(double minimum, double maximum)

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

Note: The maximum and minimum values will be rounded to match the decimals property.

 setRange(minimum, maximum);

is equivalent to:

 setMinimum(minimum);
 setMaximum(maximum);

See also minimum and maximum.

void QDoubleSpinBox::setStepType(QAbstractSpinBox::StepType stepType)

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.

It also works for any decimal values, 0.041 is increased to 0.042 by stepping once.

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.

Note: Setter function for property stepType.

This function was introduced in Qt 5.12.

See also stepType().

[virtual] QString QDoubleSpinBox::textFromValue(double value) const

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 using QWidget::locale().toString(value, QLatin1Char('f'), decimals()) and will remove the thousand separator unless setGroupSeparatorShown() is set. Reimplementations may return anything.

Note: QDoubleSpinBox 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().

See also valueFromText() and QLocale::groupSeparator().

[override virtual] QValidator::State QDoubleSpinBox::validate(QString &text, int &pos) const

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

[virtual] double QDoubleSpinBox::valueFromText(const QString &text) const

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

See also textFromValue() and validate().