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QSpinBox ClassThe QSpinBox class provides a spin box widget. More... #include <QSpinBox>Inherits: QAbstractSpinBox. Public Types
Properties
Public Functions
Public Slots
Signals
Protected Functions
Reimplemented Protected Functions
Additional Inherited Members
Detailed DescriptionThe QSpinBox class provides a spin box widget. QSpinBox is designed to handle integers and discrete sets of values (e.g., month names); use QDoubleSpinBox for floating point values. QSpinBox allows the user to choose a value by clicking the up/down buttons or pressing up/down on the keyboard to increase/decrease the value currently displayed. The user can also type the value in manually. The spin box supports integer values but can be extended to use different strings with validate(), textFromValue() and valueFromText(). Every time the value changes QSpinBox emits the valueChanged() signals. The current value can be fetched with value() and set with setValue(). Clicking the up/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 behaviour 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() and setSingleStep(). Most spin boxes are directional, but QSpinBox can also operate as a circular spin box, i.e. if the range is 0-99 and the current value is 99, 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() and setSuffix(). The text in the spin box is retrieved with text() (which includes any prefix() and 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 QSpinBox.
Subclassing QSpinBoxIf using prefix(), suffix(), and specialValueText() don't provide enough control, you subclass QSpinBox and reimplement valueFromText() and textFromValue(). For example, here's the code for a custom spin box that allows the user to enter icon sizes (e.g., "32 x 32"): int IconSizeSpinBox::valueFromText(const QString &text) const { QRegExp regExp(tr("(\\d+)(\\s*[xx]\\s*\\d+)?")); if (regExp.exactMatch(text)) { return regExp.cap(1).toInt(); } else { return 0; } } QString IconSizeSpinBox::textFromValue(int value) const { return tr("%1 x %1").arg(value); } See the Icons example for the full source code. See also QDoubleSpinBox, QDateTimeEdit, QSlider, and Spin Boxes Example. Property Documentation
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| QString | cleanText() const |
See also text, QSpinBox::prefix, and QSpinBox::suffix.
maximum : int
This property holds the maximum value of the spin box.
When setting this property the minimum is adjusted if necessary, to ensure that the range remains valid.
The default maximum value is 99.
Access functions:
| int | maximum() const |
| void | setMaximum(int max) |
See also setRange() and specialValueText.
minimum : int
This property holds the minimum value of the spin box.
When setting this property the maximum is adjusted if necessary to ensure that the range remains valid.
The default minimum value is 0.
Access functions:
| int | minimum() const |
| void | setMinimum(int min) |
See also setRange() and specialValueText.
prefix : QString
This property holds the spin box's prefix.
The prefix is prepended to the start of the displayed value. Typical use is to display a unit of measurement or a currency symbol. For example:
sb->setPrefix("$");
To turn off the prefix display, set this property to an empty string. The default is no prefix. The prefix is not displayed when value() == minimum() and specialValueText() is set.
If no prefix is set, prefix() returns an empty string.
Access functions:
| QString | prefix() const |
| void | setPrefix(const QString & prefix) |
See also suffix(), setSuffix(), specialValueText(), and setSpecialValueText().
singleStep : int
This property holds the step value.
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. Setting a singleStep value of less than 0 does nothing.
Access functions:
| int | singleStep() const |
| void | setSingleStep(int val) |
suffix : QString
This property holds the suffix of the spin box.
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:
sb->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.
Access functions:
| QString | suffix() const |
| void | setSuffix(const QString & suffix) |
See also prefix(), setPrefix(), specialValueText(), and setSpecialValueText().
value : int
This property holds the value of the spin box.
setValue() will emit valueChanged() if the new value is different from the old one.
Access functions:
| int | value() const |
| void | setValue(int val) |
Notifier signal:
| void | valueChanged(int i) |
| void | valueChanged(const QString & text) |
Member Function Documentation
QSpinBox::QSpinBox(QWidget * parent = 0)
Constructs a spin box with 0 as minimum value and 99 as maximum value, a step value of 1. The value is initially set to 0. It is parented to parent.
See also setMinimum(), setMaximum(), and setSingleStep().
bool QSpinBox::event(QEvent * event) [virtual protected]
Reimplemented from QObject::event().
void QSpinBox::fixup(QString & input) const [virtual protected]
Reimplemented from QAbstractSpinBox::fixup().
void QSpinBox::setRange(int minimum, int maximum)
Convenience function to set the minimum, and maximum values with a single function call.
setRange(minimum, maximum);
is equivalent to:
setMinimum(minimum); setMaximum(maximum);
QString QSpinBox::textFromValue(int value) const [virtual protected]
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 in the standard way using QWidget::locale().toString(), but with the thousand separator removed. Reimplementations may return anything. (See the example in the detailed description.)
Note: QSpinBox 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() and validate()
See also valueFromText(), validate(), and QLocale::groupSeparator().
QValidator::State QSpinBox::validate(QString & text, int & pos) const [virtual protected]
Reimplemented from QAbstractSpinBox::validate().
int QSpinBox::valueFromText(const QString & text) const [virtual protected]
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.
Note: QSpinBox handles specialValueText() separately; this function is only concerned with the other values.
See also textFromValue() and validate().