QDoubleValidator Class▲
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Header: QDoubleValidator
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CMake:
find_package(Qt6 REQUIRED COMPONENTS Gui)
target_link_libraries(mytarget PRIVATE Qt6::Gui)
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qmake: QT += gui
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Inherited By:
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Instantiated By: qml-qtquick-doublevalidator.xml
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Inherits: QValidator
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Inherited By:
Detailed Description▲
QDoubleValidator provides an upper bound, a lower bound, and a limit on the number of digits after the decimal point.
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.
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▲
Member Type Documentation▲
enum QDoubleValidator::Notation▲
This enum defines the allowed notations for entering a double.
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Constant |
Value |
Description |
|---|---|---|
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QDoubleValidator::StandardNotation |
0 |
The string is written as a standard number (i.e. 0.015). |
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QDoubleValidator::ScientificNotation |
1 |
The string is written in scientific form. It may have an exponent part(i.e. 1.5E-2). |
Property Documentation▲
bottom : double▲
This property holds the validator's minimum acceptable value
By default, this property contains a value of -infinity.
Access functions:
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double bottom() const
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void setBottom(double)
Notifier signal:
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void bottomChanged(double bottom)
See Also▲
See also setRange()
decimals : int▲
This property holds the validator's maximum number of digits after the decimal point
By default, this property contains a value of -1, which means any number of digits is accepted.
Access functions:
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int decimals() const
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void setDecimals(int)
Notifier signal:
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void decimalsChanged(int decimals)
See Also▲
See also setRange()
notation : Notation▲
This property holds the notation of how a string can describe a number
By default, this property is set to ScientificNotation.
Access functions:
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notation() const
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void setNotation(QDoubleValidator::Notation)
Notifier signal:
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void notationChanged( notation)
See Also▲
See also Notation
top : double▲
Member Function Documentation▲
[explicit] 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.
[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"If decimals() is set to, and the string provides, more than std::numeric_limits<double>::digits10, digits beyond that many in the fractional part may be changed. The resulting string shall encode the same floating-point number, when parsed to a double.
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.
Setting the number of decimals to -1 effectively sets it to unlimited. This is also the value used by a default-constructed validator.
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.