QDoubleSpinBox 类提供采用双精度的自旋框 Widget。 更多...
| 头： | #include <QDoubleSpinBox> |
| qmake: | QT += widgets |
| 继承： | QAbstractSpinBox |
|
| QDoubleSpinBox (QWidget * parent = nullptr) | |
| virtual | ~QDoubleSpinBox () |
| QString | cleanText () const |
| int | decimals () const |
| double | maximum () const |
| double | minimum () const |
| QString | prefix () const |
| void | setDecimals (int prec ) |
| void | setMaximum (double max ) |
| void | setMinimum (double min ) |
| void | setPrefix (const QString & prefix ) |
| void | setRange (double minimum , double maximum ) |
| void | setSingleStep (double val ) |
| void | setStepType (QAbstractSpinBox::StepType stepType ) |
| void | setSuffix (const QString & suffix ) |
| double | singleStep () const |
| QAbstractSpinBox::StepType | stepType () const |
| QString | suffix () const |
| virtual QString | textFromValue (double value ) const |
| double | value () const |
| virtual double | valueFromText (const QString & text ) const |
| virtual void | fixup (QString & input ) const override |
| virtual QValidator::State | validate (QString & text , int & pos ) const override |
| void | setValue (double val ) |
| void | textChanged (const QString & text ) |
| void | valueChanged (double d ) |
QDoubleSpinBox allows the user to choose a value by clicking the up and down buttons or by pressing Up or Down on the keyboard to increase or decrease the value currently displayed. The user can also type the value in manually. The spin box supports double values but can be extended to use different strings with validate (), textFromValue () 和 valueFromText ().
Every time the value changes QDoubleSpinBox emits valueChanged () 和 textChanged () signals, the former providing a double and the latter a QString 。 textChanged () signal provides the value with both prefix () 和 suffix (). The current value can be fetched with value () 和设置采用 setValue ().
Note: QDoubleSpinBox will round numbers so they can be displayed with the current precision. In a QDoubleSpinBox with decimals set to 2, calling setValue (2.555) will cause value () to return 2.56.
Clicking the up and down buttons or using the keyboard accelerator's Up and Down arrows will increase or decrease the current value in steps of size singleStep (). If you want to change this behavior you can reimplement the virtual function stepBy (). The minimum and maximum value and the step size can be set using one of the constructors, and can be changed later with setMinimum (), setMaximum () 和 setSingleStep (). The spinbox has a default precision of 2 decimal places but this can be changed using setDecimals ().
Most spin boxes are directional, but QDoubleSpinBox can also operate as a circular spin box, i.e. if the range is 0.0-99.9 and the current value is 99.9, clicking "up" will give 0 if wrapping () is set to true. Use setWrapping () if you want circular behavior.
The displayed value can be prepended and appended with arbitrary strings indicating, for example, currency or the unit of measurement. See setPrefix () 和 setSuffix (). The text in the spin box is retrieved with text () (which includes any prefix () 和 suffix ()), or with cleanText () (which has no prefix (), no suffix () and no leading or trailing whitespace).
It is often desirable to give the user a special (often default) choice in addition to the range of numeric values. See setSpecialValueText () for how to do this with QDoubleSpinBox.
注意： The displayed value of the QDoubleSpinBox is limited to 18 characters in addition to eventual prefix and suffix content. This limitation is used to keep the double spin box usable even with extremely large values.
另请参阅 QSpinBox , QDateTimeEdit , QSlider ，和 自旋框范例 .
This property holds the text of the spin box excluding any prefix, suffix, or leading or trailing whitespace.
访问函数：
| QString | cleanText () const |
另请参阅 text , QDoubleSpinBox::prefix ，和 QDoubleSpinBox::suffix .
This property holds the precision of the spin box, in decimals
Sets how many decimals the spinbox will use for displaying and interpreting doubles.
警告： The maximum value for decimals is DBL_MAX_10_EXP + DBL_DIG (ie. 323) because of the limitations of the double type.
Note: The maximum, minimum and value might change as a result of changing this property.
访问函数：
| int | decimals () const |
| void | setDecimals (int prec ) |
此特性保持自旋框的最大值
When setting this property the minimum is adjusted if necessary, to ensure that the range remains valid.
默认最大值为 99.99。
Note: The maximum value will be rounded to match the decimals property.
访问函数：
| double | maximum () const |
| void | setMaximum (double max ) |
另请参阅 decimals and setRange ().
此特性保持自旋框的最小值
When setting this property the maximum is adjusted if necessary to ensure that the range remains valid.
默认最小值为 0.0。
Note: The minimum value will be rounded to match the decimals property.
访问函数：
| double | minimum () const |
| void | setMinimum (double min ) |
另请参阅 decimals , setRange ()，和 specialValueText .
此特性保持自旋框的前缀
前缀会被前置到显示值的开头。典型用途是显示度量单位 (或货币符号)。例如：
spinbox->setPrefix("$");
要关闭前缀显示，把此特性设为空字符串。默认为无前缀。前缀不显示，当 value () == minimum () 和 specialValueText () is set.
prefix() 返回空字符串，若未设置前缀。
访问函数：
| QString | prefix () const |
| void | setPrefix (const QString & prefix ) |
另请参阅 suffix (), setSuffix (), specialValueText ()，和 setSpecialValueText ().
此特性保持步幅值
When the user uses the arrows to change the spin box's value the value will be incremented/decremented by the amount of the singleStep. The default value is 1.0. Setting a singleStep value of less than 0 does nothing.
访问函数：
| double | singleStep () const |
| void | setSingleStep (double val ) |
This property holds the step type.
The step type can be single step or adaptive decimal step.
访问函数：
| QAbstractSpinBox::StepType | stepType () const |
| void | setStepType (QAbstractSpinBox::StepType stepType ) |
此特性保持自旋框的后缀
The suffix is appended to the end of the displayed value. Typical use is to display a unit of measurement or a currency symbol. For example:
spinbox->setSuffix(" km");
To turn off the suffix display, set this property to an empty string. The default is no suffix. The suffix is not displayed for the minimum () if specialValueText () is set.
If no suffix is set, suffix() returns an empty string.
访问函数：
| QString | suffix () const |
| void | setSuffix (const QString & suffix ) |
另请参阅 prefix (), setPrefix (), specialValueText ()，和 setSpecialValueText ().
This property holds the value of the spin box
setValue() will emit valueChanged () if the new value is different from the old one. The value property has a second notifier signal which includes the spin box's prefix and suffix.
Note: The value will be rounded so it can be displayed with the current setting of decimals.
访问函数：
| double | 值 () const |
| void | setValue (double val ) |
通知程序信号：
| void | valueChanged (double d ) |
另请参阅 decimals .
Constructs a spin box with 0.0 as minimum value and 99.99 as maximum value, a step value of 1.0 and a precision of 2 decimal places. The value is initially set to 0.00. The spin box has the given parent .
另请参阅 setMinimum (), setMaximum ()，和 setSingleStep ().
[signal]
void
QDoubleSpinBox::
textChanged
(const
QString
&
text
)
此信号被发射每当自旋框文本改变时。新文本被传入 text with prefix () 和 suffix ().
该函数在 Qt 5.14 引入。
[signal]
void
QDoubleSpinBox::
valueChanged
(
double
d
)
This signal is emitted whenever the spin box's value is changed. The new value is passed in d .
注意： 通知程序信号对于特性 value .
注意： 信号 valueChanged 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：
connect(doubleSpinBox, QOverload<double>::of(&QDoubleSpinBox::valueChanged), [=](double d){ /* ... */ });
[virtual]
QDoubleSpinBox::
~QDoubleSpinBox
()
析构函数。
[override virtual]
void
QDoubleSpinBox::
fixup
(
QString
&
input
) const
重实现： QAbstractSpinBox::fixup (QString &input) const.
Convenience function to set the minimum and maximum values with a single function call.
Note: The maximum and minimum values will be rounded to match the decimals property.
setRange(minimum, maximum);
相当于：
setMinimum(minimum); setMaximum(maximum);
Sets the step type for the spin box to stepType , which is single step or adaptive decimal step.
Adaptive decimal step means that the step size will continuously be adjusted to one power of ten below the current value . So when the value is 1100, the step is set to 100, so stepping up once increases it to 1200. For 1200 stepping up takes it to 1300. For negative values, stepping down from -1100 goes to -1200.
It also works for any decimal values, 0.041 is increased to 0.042 by stepping once.
Step direction is taken into account to handle edges cases, so that stepping down from 100 takes the value to 99 instead of 90. Thus a step up followed by a step down -- or vice versa -- always lands on the starting value; 99 -> 100 -> 99.
Setting this will cause the spin box to disregard the value of singleStep , although it is preserved so that singleStep comes into effect if adaptive decimal step is later turned off.
注意： Setter 函数对于特性 stepType .
该函数在 Qt 5.12 引入。
另请参阅 stepType ().
[virtual]
QString
QDoubleSpinBox::
textFromValue
(
double
value
) const
This virtual function is used by the spin box whenever it needs to display the given value . The default implementation returns a string containing value printed using QWidget::locale ().toString( value , QLatin1Char ('f'), decimals ()) and will remove the thousand separator unless setGroupSeparatorShown () is set. Reimplementations may return anything.
注意： QDoubleSpinBox does not call this function for specialValueText () and that neither prefix () nor suffix () should be included in the return value.
If you reimplement this, you may also need to reimplement valueFromText ().
另请参阅 valueFromText () 和 QLocale::groupSeparator ().
[override virtual]
QValidator::State
QDoubleSpinBox::
validate
(
QString
&
text
,
int
&
pos
) const
重实现： QAbstractSpinBox::validate (QString &input, int &pos) const.
[virtual]
double
QDoubleSpinBox::
valueFromText
(const
QString
&
text
) const
This virtual function is used by the spin box whenever it needs to interpret text entered by the user as a value.
Subclasses that need to display spin box values in a non-numeric way need to reimplement this function.
注意： QDoubleSpinBox handles specialValueText () separately; this function is only concerned with the other values.
另请参阅 textFromValue () 和 validate ().