QDoubleValidator class provides range checking of floating-point numbers. 更多...
| 头： | #include <QDoubleValidator> |
| qmake: | QT += gui |
| 实例化： | DoubleValidator |
| 继承： | QValidator |
| enum | Notation { StandardNotation, ScientificNotation } |
| QDoubleValidator (QObject * parent = Q_NULLPTR) | |
| QDoubleValidator (double bottom , double top , int decimals , QObject * parent = Q_NULLPTR) | |
| ~QDoubleValidator () | |
| double | bottom () const |
| int | decimals () const |
| Notation | notation () const |
| void | setBottom ( double ) |
| void | setDecimals ( int ) |
| void | setNotation ( Notation ) |
| virtual void | setRange (double minimum , double maximum , int decimals = 0) |
| void | setTop ( double ) |
| double | top () const |
| virtual QValidator::State | validate (QString & input , int & pos ) const |
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 () 函数。
You can set the acceptable range in one call with setRange (), or with setBottom () 和 setTop (). Set the number of decimal places with setDecimals ()。 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.
注意： QLocale::NumberOptions 设置在 locale () 还会影响数字的解释方式。例如，由于 QLocale::RejectGroupSeparator 默认未设置，验证器将接受组分隔符。因此推荐使用 QLocale::toDouble () 获得数值。
另请参阅 QIntValidator , QRegExpValidator , QLocale::toDouble ()，和 行编辑范例 .
This enum defines the allowed notations for entering a double.
| 常量 | 值 | 描述 |
|---|---|---|
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). |
该枚举在 Qt 4.3 引入或被修改。
This property holds the validator's minimum acceptable value
By default, this property contains a value of -infinity.
访问函数：
| double | bottom () const |
| void | setBottom ( double ) |
另请参阅 setRange ().
This property holds the validator's maximum number of digits after the decimal point
By default, this property contains a value of 1000.
访问函数：
| int | decimals () const |
| void | setDecimals ( int ) |
另请参阅 setRange ().
This property holds the notation of how a string can describe a number
默认情况下，此特性被设为 ScientificNotation .
该特性在 Qt 4.3 引入。
访问函数：
| Notation | notation () const |
| void | setNotation ( Notation ) |
另请参阅 Notation .
This property holds the validator's maximum acceptable value
By default, this property contains a value of infinity.
访问函数：
| double | top () const |
| void | setTop ( double ) |
另请参阅 setRange ().
Constructs a validator object with a parent object that accepts any double.
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.
销毁验证器。
[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.
[virtual]
QValidator::State
QDoubleValidator::
validate
(
QString
&
input
,
int
&
pos
) const
重实现自 QValidator::validate ().
返回 Acceptable if the string input contains a double that is within the valid range and is in the correct format.
返回 中间体 if input contains a double that is outside the range or is in the wrong format; e.g. with too many digits after the decimal point or is empty.
返回 Invalid 若 input is not a double.
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 被返回。若 notation () 被设为 StandardNotation , and the input contains more digits before the decimal point than a double in the valid range may have, Invalid 被返回。若 notation () 是 ScientificNotation , and the input is not in the valid range, 中间体 is returned. The value may yet become valid by changing the exponent.
默认情况下， pos 参数并未用于此验证器。