QDoubleValidator Class

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.

[override virtual, since 6.3] void QDoubleValidator::fixup(QString &input) const

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

This is an overloaded function.

Attempts to fix the input string to an Acceptable representation of a double.

The format of the number is determined by notation(), decimals(), locale() and the latter's numberOptions().

To comply with notation(), when ScientificNotation is used, the fixed value will be represented in its normalized form, which means that any non-zero value will have one non-zero digit before the decimal point.

QString input = "0.98765e2";
QDoubleValidator val;
val.setLocale(QLocale::C);
val.setNotation(QDoubleValidator::ScientificNotation);
val.fixup(input); // input == "9.8765e+01"

To comply with decimals(), when it is -1 the number of digits used will be determined by QLocale::FloatingPointShortest. Otherwise, the fractional part of the number is truncated (with rounding, as appropriate) if its length exceeds decimals(). When notation() is ScientificNotation this is done after the number has been put into its normalized form.

input = "-1234.6789";
val.setDecimals(2);
val.setLocale(QLocale::C);
val.setNotation(QDoubleValidator::StandardNotation);
val.fixup(input); // input == "-1234.68"

This function was introduced in Qt 6.3.

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

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

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

This is an overloaded function.

Sets the validator to accept doubles from minimum to maximum inclusive without changing the number of 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.