QSlider Class

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

Header:	#include <QSlider>
qmake:	QT += widgets
Inherits:	QAbstractSlider

• List of all members, including inherited members

Public Types

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

Properties

• tickInterval : int
• tickPosition : TickPosition

Public Functions

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

Reimplemented Public Functions

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

Protected Functions

void	initStyleOption(QStyleOptionSlider *option) const

Reimplemented Protected Functions

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

Detailed Description

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:

Signal	Description
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).

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.

Constant	Value	Description
QSlider::NoTicks	0	Do not draw any tick marks.
QSlider::TicksBothSides	3	Draw tick marks on both sides of the groove.
QSlider::TicksAbove	1	Draw tick marks above the (horizontal) slider
QSlider::TicksBelow	2	Draw tick marks below the (horizontal) slider
QSlider::TicksLeft	TicksAbove	Draw tick marks to the left of the (vertical) slider
QSlider::TicksRight	TicksBelow	Draw tick marks to the right of the (vertical) slider

Member Function Documentation

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

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(QWidget *parent = nullptr)

Constructs a vertical slider with the given parent.

[virtual] QSlider::~QSlider()

Destroys this slider.

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

Reimplements: QAbstractSlider::event(QEvent *e).

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

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().

[override virtual] QSize QSlider::minimumSizeHint() const

Reimplements an access function for property: QWidget::minimumSizeHint.

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

Reimplements: QWidget::mouseMoveEvent(QMouseEvent *event).

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

Reimplements: QWidget::mousePressEvent(QMouseEvent *event).

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

Reimplements: QWidget::mouseReleaseEvent(QMouseEvent *event).

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

Reimplements: QWidget::paintEvent(QPaintEvent *event).

[override virtual] QSize QSlider::sizeHint() const

Reimplements an access function for property: QWidget::sizeHint.