Qt Reference Documentation

QSlider Class Reference

The QSlider widget provides a vertical or horizontal slider. More...

 #include <QSlider>

Inherits: QAbstractSlider.

Public Types

enum TickPosition { NoTicks, TicksBothSides, TicksAbove, TicksBelow, TicksLeft, TicksRight }


Public Functions

QSlider ( QWidget * parent = 0 )
QSlider ( Qt::Orientation orientation, QWidget * parent = 0 )
~QSlider ()
void setTickInterval ( int ti )
void setTickPosition ( TickPosition position )
int tickInterval () const
TickPosition tickPosition () const

Reimplemented Public Functions

virtual bool event ( QEvent * event )
virtual QSize minimumSizeHint () const
virtual QSize sizeHint () const

Protected Functions

void initStyleOption ( QStyleOptionSlider * option ) const

Reimplemented Protected Functions

virtual void mouseMoveEvent ( QMouseEvent * ev )
virtual void mousePressEvent ( QMouseEvent * ev )
virtual void mouseReleaseEvent ( QMouseEvent * ev )
virtual void paintEvent ( QPaintEvent * ev )

Additional Inherited Members

Detailed Description

The QSlider widget provides a vertical or horizontal slider.

The slider is the classic widget for controlling a bounded value. It lets the user move a slider handle along a horizontal or vertical groove and translates the handle's position into an integer value within the legal range.

QSlider has very few of its own functions; most of the functionality is in QAbstractSlider. The most useful functions are setValue() to set the slider directly to some value; triggerAction() to simulate the effects of clicking (useful for shortcut keys); setSingleStep(), setPageStep() to set the steps; and setMinimum() and setMaximum() to define the range of the scroll bar.

QSlider provides methods for controlling tickmarks. You can use setTickPosition() to indicate where you want the tickmarks to be, setTickInterval() to indicate how many of them you want. the currently set tick position and interval can be queried using the tickPosition() and tickInterval() functions, respectively.

QSlider inherits a comprehensive set of signals:

valueChanged()Emitted when the slider's value has changed. The tracking() determines whether this signal is emitted during user interaction.
sliderPressed()Emitted when the user starts to drag the slider.
sliderMoved()Emitted when the user drags the slider.
sliderReleased()Emitted when the user releases the slider.

QSlider only provides integer ranges. Note that although QSlider handles very large numbers, it becomes difficult for users to use a slider accurately for very large ranges.

A slider accepts focus on Tab and provides both a mouse wheel and a keyboard interface. The keyboard interface is the following:

  • Left/Right move a horizontal slider by one single step.
  • Up/Down move a vertical slider by one single step.
  • PageUp moves up one page.
  • PageDown moves down one page.
  • Home moves to the start (mininum).
  • End moves to the end (maximum).
Screenshot of a Macintosh sliderA slider shown in the Macintosh widget style.
Screenshot of a Windows XP sliderA slider shown in the Windows XP widget style.
Screenshot of a Plastique sliderA slider shown in the Plastique widget style.

See also QScrollBar, QSpinBox, QDial, GUI Design Handbook: Slider, and Sliders Example.

Member Type Documentation

enum QSlider::TickPosition

This enum specifies where the tick marks are to be drawn relative to the slider's groove and the handle the user moves.

QSlider::NoTicks0Do not draw any tick marks.
QSlider::TicksBothSides3Draw tick marks on both sides of the groove.
QSlider::TicksAbove1Draw tick marks above the (horizontal) slider
QSlider::TicksBelow2Draw tick marks below the (horizontal) slider
QSlider::TicksLeftTicksAboveDraw tick marks to the left of the (vertical) slider
QSlider::TicksRightTicksBelowDraw tick marks to the right of the (vertical) slider

Property Documentation

tickInterval : int

This property holds the interval between tickmarks.

This is a value interval, not a pixel interval. If it is 0, the slider will choose between singleStep() and pageStep().

The default value is 0.

Access functions:

int tickInterval () const
void setTickInterval ( int ti )

See also tickPosition, lineStep(), and pageStep().

tickPosition : TickPosition

This property holds the tickmark position for this slider.

The valid values are described by the QSlider::TickPosition enum.

The default value is QSlider::NoTicks.

Access functions:

TickPosition tickPosition () const
void setTickPosition ( TickPosition position )

See also tickInterval.

Member Function Documentation

QSlider::QSlider ( QWidget * parent = 0 )

Constructs a vertical slider with the given parent.

QSlider::QSlider ( Qt::Orientation orientation, QWidget * parent = 0 )

Constructs a slider with the given parent. The orientation parameter determines whether the slider is horizontal or vertical; the valid values are Qt::Vertical and Qt::Horizontal.

QSlider::~QSlider ()

Destroys this slider.

bool QSlider::event ( QEvent * event ) [virtual]

Reimplemented from QObject::event().

void QSlider::initStyleOption ( QStyleOptionSlider * option ) const [protected]

Initialize option with the values from this QSlider. This method is useful for subclasses when they need a QStyleOptionSlider, but don't want to fill in all the information themselves.

See also QStyleOption::initFrom().

QSize QSlider::minimumSizeHint () const [virtual]

Reimplemented from QWidget::minimumSizeHint().

void QSlider::mouseMoveEvent ( QMouseEvent * ev ) [virtual protected]

Reimplemented from QWidget::mouseMoveEvent().

void QSlider::mousePressEvent ( QMouseEvent * ev ) [virtual protected]

Reimplemented from QWidget::mousePressEvent().

void QSlider::mouseReleaseEvent ( QMouseEvent * ev ) [virtual protected]

Reimplemented from QWidget::mouseReleaseEvent().

void QSlider::paintEvent ( QPaintEvent * ev ) [virtual protected]

Reimplemented from QWidget::paintEvent().

QSize QSlider::sizeHint () const [virtual]

Reimplemented from QWidget::sizeHint().