QDoubleValidator Class

The QDoubleValidator class provides range checking of floating-point numbers. More...

Header:	#include <QDoubleValidator>
CMake:	find_package(Qt6 COMPONENTS Gui REQUIRED) target_link_libraries(mytarget PRIVATE Qt6::Gui)
qmake:	QT += gui
Inherits:	QValidator

• List of all members, including inherited members

Public Types

enum	Notation { StandardNotation, ScientificNotation }

Properties

• bottom : double
• decimals : int
• notation : Notation
• top : double

Public Functions

	QDoubleValidator(double bottom, double top, int decimals, QObject *parent = nullptr)
	QDoubleValidator(QObject *parent = nullptr)
virtual	~QDoubleValidator()
double	bottom() const
int	decimals() const
QDoubleValidator::Notation	notation() const
void	setBottom(double)
void	setDecimals(int)
void	setNotation(QDoubleValidator::Notation)
void	setRange(double minimum, double maximum, int decimals = 0)
void	setTop(double)
double	top() const

Reimplemented Public Functions

virtual QValidator::State

validate(QString &input, int &pos) const override

Signals

void	bottomChanged(double bottom)
void	decimalsChanged(int decimals)
void	notationChanged(QDoubleValidator::Notation notation)
void	topChanged(double top)

Detailed Description

QDoubleValidator provides an upper bound, a lower bound, and a limit on the number of digits after the decimal point. It does not provide a fixup() function.

You can set the acceptable range in one call with setRange(), or with setBottom() and setTop(). Set the number of decimal places with setDecimals(). The validate() function returns the validation state.

QDoubleValidator uses its locale() to interpret the number. For example, in the German locale, "1,234" will be accepted as the fractional number 1.234. In Arabic locales, QDoubleValidator will accept Arabic digits.

See also QIntValidator, QRegularExpressionValidator, QLocale::toDouble(), and Line Edits Example.

Member Type Documentation

enum QDoubleValidator::Notation

This enum defines the allowed notations for entering a double.

Constant	Value	Description
QDoubleValidator::StandardNotation	0	The string is written as a standard number (i.e. 0.015).
QDoubleValidator::ScientificNotation	1	The string is written in scientific form. It may have an exponent part(i.e. 1.5E-2).

Member Function Documentation

QDoubleValidator::QDoubleValidator(double bottom, double top, int decimals, QObject *parent = nullptr)

Constructs a validator object with a parent object. This validator will accept doubles from bottom to top inclusive, with up to decimals digits after the decimal point.

QDoubleValidator::QDoubleValidator(QObject *parent = nullptr)

Constructs a validator object with a parent object that accepts any double.

[virtual] QDoubleValidator::~QDoubleValidator()

Destroys the validator.

void QDoubleValidator::setRange(double minimum, double maximum, int decimals = 0)

Sets the validator to accept doubles from minimum to maximum inclusive, with at most decimals digits after the decimal point.

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

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

Returns Acceptable if the string input contains a double that is within the valid range and is in the correct format.

Returns Intermediate if input contains a double that is outside the range or is in the wrong format; e.g. is empty.

Returns Invalid if the input is not a double or with too many digits after the decimal point.

Note: If the valid range consists of just positive doubles (e.g. 0.0 to 100.0) and input is a negative double then Invalid is returned. If notation() is set to StandardNotation, and the input contains more digits before the decimal point than a double in the valid range may have, Invalid is returned. If notation() is ScientificNotation, and the input is not in the valid range, Intermediate is returned. The value may yet become valid by changing the exponent.

By default, the pos parameter is not used by this validator.