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The QSpinBox class provides a spin box widget (spin button). More...
#include <qspinbox.h>
Inherits QWidget and QRangeControl.
The QSpinBox class provides a spin box widget (spin button).
QSpinBox allows the user to choose a value either by clicking the up/down buttons to increase/decrease the value currently displayed or by typing the value directly into the spin box. If the value is entered directly into the spin box, \Key Enter must be pressed to apply the new value. The value is usually an integer.
Every time the value changes QSpinBox emits the valueChanged() signal. The current value can be fetched with value() and set with setValue().
The spin box keeps the value within a numeric range, and to multiples of the lineStep() size (see QRangeControl for details). 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 lineStep(). The minimum and maximum value and the step size can be set using one of the constructors, and can be changed later with setMinValue(), setMaxValue() and setLineStep().
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. 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). currentValueText() returns the spin box's current value as text.
Normally the spin box displays up and down arrows in the buttons. You can use setButtonSymbols() to change the display to show + and - symbols if this is clearer for your intended purpose. In either case the up and down arrow keys work as expected.
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.
The default QWidget::focusPolicy() is StrongFocus.
If using prefix(), suffix() and specialValueText() don't provide enough control, you can ignore them and subclass QSpinBox instead.
QSpinBox can easily be subclassed to allow the user to input things other than an integer value as long as the allowed input can be mapped to a range of integers. This can be done by overriding the virtual functions mapValueToText() and mapTextToValue(), and setting another suitable validator using setValidator().
For example, these functions could be changed so that the user provided values from 0.0 to 10.0, or -1 to signify 'Auto', while the range of integers used inside the program would be -1 to 100:
class MySpinBox : public QSpinBox
{
Q_OBJECT
public:
...
QString mapValueToText( int value )
{
if ( value == -1 ) // special case
return QString( "Auto" );
return QString( "%1.%2" ) // 0.0 to 10.0
.arg( value / 10 ).arg( value % 10 );
}
int mapTextToValue( bool *ok )
{
if ( text() == "Auto" ) // special case
return -1;
return (int) ( 10 * text().toFloat() ); // 0 to 100
}
};
See also QScrollBar, QSlider, GUI Design Handbook: Spin Box and Basic Widgets.
See also QSpinBox::buttonSymbols.
See also minValue, maxValue, setRange(), lineStep and setSteps().
The widget's parent is parent and the spin box is called name.
See also minValue, maxValue, setRange(), lineStep and setSteps().
Returns the current button symbol mode. See the "buttonSymbols" property for details.
Returns the text of the spin box with any prefix() or suffix() and any whitespace at the start and end removed. See the "cleanText" property for details.
Reimplemented from QObject.
The default implementation of this function interprets the new text using mapTextToValue(). If mapTextToValue() is successful, it changes the spin box's value; if not, the value is left unchanged.
See also editor().
Returns the line step. See the "lineStep" property for details.
Subclasses that need to display spin box values in a non-numeric way need to reimplement this function.
Note that Qt handles specialValueText() separately; this function is only concerned with the other values.
The default implementation tries to interpret the text() as an integer in the standard way and returns the integer value.
See also interpretText() and mapValueToText().
Note that Qt does not call this function for specialValueText() and that neither prefix() nor suffix() are included in the return value.
If you reimplement this, you may also need to reimplement mapTextToValue().
See also updateDisplay() and mapTextToValue().
Returns the maximum value of the spin box. See the "maxValue" property for details.
Returns the minimum value of the spin box. See the "minValue" property for details.
Returns the prefix of the spin box. See the "prefix" property for details.
Reimplemented from QRangeControl.
Sets the current button symbol mode. See the "buttonSymbols" property for details.
Sets the line step. See the "lineStep" property for details.
Sets the maximum value of the spin box. See the "maxValue" property for details.
Sets the minimum value of the spin box. See the "minValue" property for details.
Sets the prefix of the spin box to text. See the "prefix" property for details.
Sets the special-value text to text. See the "specialValueText" property for details.
Sets the suffix of the spin box to text. See the "suffix" property for details.
Use setValidator(0) to turn off input validation (entered input will still be clamped to the range of the spinbox).
Sets the value of the spin box to value. See the "value" property for details.
Sets whether it is possible to step the value from the highest value to the lowest value and vice versa to on. See the "wrapping" property for details.
Returns the special-value text. See the "specialValueText" property for details.
See also stepUp(), subtractLine(), lineStep, setSteps(), value and value.
See also stepDown(), addLine(), lineStep, setSteps(), value and value.
Returns the suffix of the spin box. See the "suffix" property for details.
Returns the text of the spin box, including any prefix() and suffix(). See the "text" property for details.
See also mapValueToText().
See also setValidator() and QValidator.
Returns the value of the spin box. See the "value" property for details.
Reimplemented from QRangeControl.
This signal is emitted every time the value of the spin box changes; the new value is passed in value. This signal will be emitted as a result of a call to setValue(), or because the user changed the value by using a keyboard accelerator or mouse click, etc.
Note that the valueChanged() signal is emitted every time, not just for the "final" step; i.e. if the user clicks "up" three times, this signal is emitted three times.
See also value.
Examples: listbox/listbox.cpp, qfd/fontdisplayer.cpp and scribble/scribble.cpp.
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This signal is emitted whenever the valueChanged( int ) signal is emitted, i.e. every time the value of the spin box changes (whatever the cause, e.g. by setValue(), by a keyboard accelerator, by mouse clicks, etc.).
The valueText parameter is the same string that is displayed in the edit field of the spin box.
See also value, prefix, suffix and specialValueText.
Returns TRUE if it is possible to step the value from the highest value to the lowest value and vice versa; otherwise returns FALSE. See the "wrapping" property for details.
This property holds the current button symbol mode.
The possible values can be either UpDownArrows or PlusMinus. The default is UpDownArrows.
See also ButtonSymbols.
Set this property's value with setButtonSymbols() and get this property's value with buttonSymbols().
This property holds the text of the spin box with any prefix() or suffix() and any whitespace at the start and end removed.
Get this property's value with cleanText().
See also text, prefix and suffix.
This property holds the line step.
When the user uses the arrows to change the spin box's value the value will be incremented/decremented by the amount of the line step.
The setLineStep() function calls the virtual stepChange() function if the new line step is different from the previous setting.
See also QRangeControl::setSteps() and setRange().
Set this property's value with setLineStep() and get this property's value with lineStep().
This property holds the maximum value of the spin box.
When setting this property, the QSpinBox::minValue is adjusted so that the range remains valid if necessary.
See also setRange() and specialValueText.
Set this property's value with setMaxValue() and get this property's value with maxValue().
This property holds the minimum value of the spin box.
When setting this property, the QSpinBox::maxValue is adjusted so that the range remains valid if necessary.
See also setRange() and specialValueText.
Set this property's value with setMinValue() and get this property's value with minValue().
This property holds the prefix of the spin box.
The prefix is prepended to the start of the displayed value. Typical use is to indicate the unit of measurement to the user. 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 for the minValue() if specialValueText() is not empty.
If no prefix is set, prefix() returns a null string.
See also suffix.
Set this property's value with setPrefix() and get this property's value with prefix().
This property holds the special-value text.
If set, the spin box will display this text instead of a numeric value whenever the current value is equal to minVal(). Typical use is to indicate that this choice has a special (default) meaning.
For example, if your spin box allows the user to choose the margin width in a print dialog and your application is able to automatically choose a good margin width, you can set up the spin box like this:
QSpinBox marginBox( -1, 20, 1, parent, "marginBox" );
marginBox->setSuffix( " mm" );
marginBox->setSpecialValueText( "Auto" );
The user will then be able to choose a margin width from 0-20
millimeters or select "Auto" to leave it to the application to
choose. Your code must then interpret the spin box value of -1 as
the user requesting automatic margin width.
All values are displayed with the prefix() and suffix() (if set), except for the special value, which only shows the special value text.
To turn off the special-value text display, call this function with an empty string. The default is no special-value text, i.e. the numeric value is shown as usual.
If no special-value text is set, specialValueText() returns a null string.
Set this property's value with setSpecialValueText() and get this property's value with specialValueText().
This property holds the suffix of the spin box.
The suffix is appended to the end of the displayed value. Typical use is to indicate the unit of measurement to the user. 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 minValue() if specialValueText() is not empty.
If no suffix is set, suffix() returns a null string.
See also prefix.
Set this property's value with setSuffix() and get this property's value with suffix().
This property holds the text of the spin box, including any prefix() and suffix().
There is no default text.
See also value.
Get this property's value with text().
This property holds the value of the spin box.
Set this property's value with setValue() and get this property's value with value().
See also QRangeControl::setValue().
This property holds whether it is possible to step the value from the highest value to the lowest value and vice versa.
By default, wrapping is turned off.
If you have a range of 0..100 and wrapping is off when the user reaches 100 and presses the Up Arrow nothing will happen; but if wrapping is on the value will change from 100 to 0, then to 1, etc. When wrapping is on, navigating past the highest value takes you to the lowest and vice versa.
See also minValue, maxValue and setRange().
Set this property's value with setWrapping() and get this property's value with wrapping().
This file is part of the Qt toolkit. Copyright © 1995-2002 Trolltech. All Rights Reserved.
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