QDoubleValidator Class

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

Header:	#include <QDoubleValidator>
qmake:	QT += gui
Inherits:	QValidator

• List of all members, including inherited members
• Obsolete members

Public Types

enum	Notation { StandardNotation, ScientificNotation }

Properties

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

• 1 property inherited from QObject

Public Functions

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

• 4 public functions inherited from QValidator
• 31 public functions inherited from QObject

Static Public Members

const QMetaObject

staticMetaObject

• 9 static public members inherited from QObject

Additional Inherited Members

• 1 public slot inherited from QObject
• 1 signal inherited from QValidator
• 2 signals inherited from QObject
• 9 protected functions inherited from QObject

Detailed Description

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

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.

Note: The QLocale::NumberOptions set on the locale() also affect the way the number is interpreted. For example, since QLocale::RejectGroupSeparator is not set by default, the validator will accept group separators. It is thus recommended to use QLocale::toDouble() to obtain the numeric value.

See also QIntValidator, QRegExpValidator, 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).

This enum was introduced or modified in Qt 4.3.

Member Function Documentation

QDoubleValidator::QDoubleValidator(QObject *parent = nullptr)

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

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.

[virtual] QDoubleValidator::~QDoubleValidator()

Destroys the validator.

[virtual] 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

Reimplemented from QValidator::validate().

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.