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QSlider Class

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

Header: #include <QSlider>
CMake: find_package(Qt6 REQUIRED COMPONENTS Widgets)
target_link_libraries(mytarget PRIVATE Qt6::Widgets)
qmake: QT += widgets
Inherits: QAbstractSlider

Public Types

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


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

virtual 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 (minimum).
  • End moves to the end (maximum).

See also QScrollBar, QSpinBox, QDial, 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

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, singleStep, 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:

QSlider::TickPosition tickPosition() const
void setTickPosition(QSlider::TickPosition position)

See also tickInterval.

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).

[virtual 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.

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