QSpinBox Class Reference
^{[QtGui module]}

Subclassing QSpinBox

If 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, QSlider, and GUI Design Handbook: Slider.

Property Documentation

cleanText : const QString

This property holds the text of the spin box excluding any prefix, suffix, or leading or trailing whitespace.

Access functions:

• 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 & p )

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 & s )

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 )

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().

void QSpinBox::setRange ( int min, int max )

Convenience function to set the minimum, min, and maximum, max, values with a single function call.

    setRange(min, max);

is equivalent to:

    setMinimum(min);
    setMaximum(max);

See also minimum and maximum.

QString QSpinBox::textFromValue ( int v ) const   [virtual protected]

This virtual function is used by the spin box whenever it needs to display value v. The default implementation returns a string containing v printed in the standard way using QLocale().toString(v). 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() and validate().

void QSpinBox::valueChanged ( int i )   [signal]

This signal is emitted whenever the spin box's value is changed. The new value's integer value is passed in i.

void QSpinBox::valueChanged ( const QString & text )   [signal]

This is an overloaded member function, provided for convenience.

The new value is passed literally in text with no prefix() or suffix().

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().