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# QAbstractSlider Class Reference

The QAbstractSlider class provides an integer value within a range. More...

    #include <QAbstractSlider>

Inherits QWidget.

Inherited by QDial, QScrollBar, and QSlider.

- List of all members, including inherited members
- Compatibility members

### Public Types

- enum SliderAction { SliderNoAction, SliderSingleStepAdd, SliderSingleStepSub, SliderPageStepAdd, SliderPageStepSub, ..., SliderMove }

### Writable Properties

invertedAppearance : bool invertedControls : bool maximum : int minimum : int orientation : Qt::Orientation | pageStep : int singleStep : int sliderDown : bool tracking : bool value : int

- 33 writable properties inherited from QWidget
- 1 writable property inherited from QObject

### Read-Only Properties

- 24 read-only properties inherited from QWidget

### Public Functions

- QAbstractSlider ( QWidget * parent = 0 )
- ~QAbstractSlider ()
- void setRange ( int min, int max )
- void setSliderPosition ( int position )
- int sliderPosition () const
- void triggerAction ( SliderAction action )

- 83 public functions inherited from QWidget
- 24 public functions inherited from QObject
- 2 public functions inherited from QPaintDevice

### Public Slots

- void setValue ( int )

- 16 public slots inherited from QWidget
- 1 public slot inherited from QObject

### Signals

- void actionTriggered ( int action )
- void rangeChanged ( int min, int max )
- void sliderMoved ( int value )
- void sliderPressed ()
- void sliderReleased ()
- void valueChanged ( int value )

- 1 signal inherited from QObject

### Static Public Members

- 4 static public members inherited from QWidget
- 4 static public members inherited from QObject

### Protected Types

- enum SliderChange { SliderRangeChange, SliderOrientationChange, SliderStepsChange, SliderValueChange }

### Protected Functions

- SliderAction repeatAction () const
- void setRepeatAction ( SliderAction action, int thresholdTime = 500, int repeatTime = 50 )
- virtual void sliderChange ( SliderChange change )

- 44 protected functions inherited from QWidget
- 9 protected functions inherited from QObject

## Detailed Description

The QAbstractSlider class provides an integer value within a range.

The class is designed as a common super class for widgets like QScrollBar, QSlider and QDial.

Here are the main properties of the class:

1. value: The bounded integer that QAbstractSlider maintains.
2. minimum: The lowest possible value.
3. maximum: The highest possible value.
4. singleStep: The smaller of two natural steps that an abstract sliders provides and typically corresponds to the user pressing an arrow key.
5. pageStep: The larger of two natural steps that an abstract slider provides and typically corresponds to the user pressing PageUp or PageDown.
6. sliderPosition: The current position of the slider. If tracking is enabled (the default), this is identical to value.

Unity (1) may be viewed as a third step size. setValue() lets you set the current value to any integer in the allowed range, not just minimum() + n * singleStep() for integer values of n. Some widgets may allow the user to set any value at all; others may just provide multiples of singleStep() or pageStep().

QAbstractSlider emits a comprehensive set of signals:

Signal | Emitted when
--- | ---
valueChanged() | the value has changed. The tracking determines whether this signal is emitted during user interaction.
sliderPressed() | the user starts to drag the slider.
sliderMoved() | the user drags the slider.
sliderReleased() | the user releases the slider.
actionTriggered() | a slider action was triggerd.
rangeChanged() | a the range has changed.

QAbstractSlider provides a virtual sliderChange() function that is well suited for updating the on-screen representation of sliders. By calling triggerAction(), subclasses trigger slider actions. Two helper functions QStyle::positionFromValue() and QStyle::valueFromPosition() help subclasses and styles to map screen coordinates to logical range values.

## Member Type Documentation

### enum QAbstractSlider::SliderAction

`QAbstractSlider::SliderNoAction` |
`QAbstractSlider::SliderSingleStepAdd` |
`QAbstractSlider::SliderSingleStepSub` |
`QAbstractSlider::SliderPageStepAdd` |
`QAbstractSlider::SliderPageStepSub` |
`QAbstractSlider::SliderToMinimum` |
`QAbstractSlider::SliderToMaximum` |
`QAbstractSlider::SliderMove` |

### enum QAbstractSlider::SliderChange

`QAbstractSlider::SliderRangeChange` |
`QAbstractSlider::SliderOrientationChange` |
`QAbstractSlider::SliderStepsChange` |
`QAbstractSlider::SliderValueChange` |

## Property Documentation

### invertedAppearance : bool

This property holds whether or not a slider shows its values inverted or not.

If this property is false (the default), the minimum and maximum will be shown in its classic position for the inherited widget. If the value is true, the minimum and maximum appear at their opposite location.

Access functions:

- bool invertedAppearance () const
- void setInvertedAppearance ( bool )

### invertedControls : bool

This property holds whether or not the slider inverts its wheel and key events.

If this property is false, scrolling the mouse wheel "up" and using keys like page up will increase the slider's value towards its maximum. Otherwise pressing page up will move value towards the slider's minimum.

Access functions:

- bool invertedControls () const
- void setInvertedControls ( bool )

### maximum : int

This property holds the slider's maximum value.

When setting this property, the minimum is adjusted if necessary to ensure that the range remains valid. Also the slider's current value is adjusted to be within the new range.

Access functions:

- int maximum () const
- void setMaximum ( int )

### minimum : int

This property holds the sliders's minimum value.

When setting this property, the maximum is adjusted if necessary to ensure that the range remains valid. Also the slider's current value is adjusted to be within the new range.

Access functions:

- int minimum () const
- void setMinimum ( int )

### orientation : Qt::Orientation

This property holds the orientation of the slider.

The orientation must be Qt::Vertical (the default) or Qt::Horizontal.

Access functions:

- Qt::Orientation orientation () const
- void setOrientation ( Qt::Orientation )

### pageStep : int

This property holds the page step.

The larger of two natural steps that an abstract slider provides and typically corresponds to the user pressing PageUp or PageDown.

Access functions:

- int pageStep () const
- void setPageStep ( int )

See also singleStep.

### singleStep : int

This property holds the single step.

The smaller of two natural steps that an abstract sliders provides and typically corresponds to the user pressing an arrow key.

Access functions:

- int singleStep () const
- void setSingleStep ( int )

See also pageStep.

### sliderDown : bool

This property holds whether the slider is pressed down.

The property is set by subclasses in order to let the abstract slider know whether or not tracking has any effect.

Changing the slider down property emits the sliderPressed() and sliderReleased() signals.

Access functions:

- bool isSliderDown () const
- void setSliderDown ( bool )

### tracking : bool

This property holds whether slider tracking is enabled.

If tracking is enabled (the default), the slider emits the valueChanged() signal while the slider is being dragged. If tracking is disabled, the slider emits the valueChanged() signal only when the user releases the slider.

Access functions:

- bool hasTracking () const
- void setTracking ( bool enable )

See also sliderDown.

### value : int

This property holds the slider's current value.

The slider forces the value to be within the legal range: minimum <= value <= maximum.

Changing the value also changes the sliderPosition.

Access functions:

- int value () const
- void setValue ( int )

## Member Function Documentation

### QAbstractSlider::QAbstractSlider ( QWidget * parent = 0 )

Constructs an abstract slider.

The parent arguments is sent to the QWidget constructor.

The minimum defaults to 0, the maximum to 99, with a singleStep size of 1 and a pageStep size of 10, and an initial value of 0.

### QAbstractSlider::~QAbstractSlider ()

Destroys the slider.

### void QAbstractSlider::actionTriggered ( int action ) `[signal]`

This signal is emitted when the slider action action is triggered. Actions are `SliderSingleStepAdd`, `SliderSingleStepSub`, `SliderPageStepAdd`, `SliderPageStepSub`, `SliderToMinimum`, `SliderToMaximum`, and `SliderMove`.

When the signal is emitted, the sliderPosition has been adjusted according to the action, but the value has not yet been propagated (meaning the valueChanged() signal was not yet emitted), and the visual display has not been updated. In slots connected to this signal you can thus safely adjust any action by calling setSliderPosition() yourself, based on both the action and the slider's value.

See also triggerAction().

### void QAbstractSlider::rangeChanged ( int min, int max ) `[signal]`

This signal is emitted when the slider range has changed, with min being the new minimum, and max being the new maximum.

See also minimum and maximum.

### SliderAction QAbstractSlider::repeatAction () const `[protected]`

Returns the current repeat action.

See also setRepeatAction().

### void QAbstractSlider::setRange ( int min, int max )

Sets the slider's minimum to min and its maximum to max.

If max is smaller than min, min becomes the only legal value.

See also minimum and maximum.

### void QAbstractSlider::setRepeatAction ( SliderAction action, int thresholdTime = 500, int repeatTime = 50 ) `[protected]`

Sets action action to be triggered repetitively in intervals of repeatTime, after an initial delay of thresholdTime.

See also triggerAction() and repeatAction().

### void QAbstractSlider::setSliderPosition ( int position )

Sets the current slider position to the given position.

See also sliderPosition().

### void QAbstractSlider::sliderChange ( SliderChange change ) `[virtual protected]`

Reimplement this virtual function to track slider changes such as `SliderRangeChange`, `SliderOrientationChange`, `SliderStepsChange`, or `SliderValueChange`. The default implementation only updates the display and ignores the change parameter.

### void QAbstractSlider::sliderMoved ( int value ) `[signal]`

This signal is emitted when the slider is dragged by the user, with the new slider value as an argument.

This signal is emitted even when tracking is turned off.

See also tracking() and valueChanged().

### int QAbstractSlider::sliderPosition () const

Returns the slider position.

If tracking is enabled (the default), this is identical to value.

See also setSliderPosition().

### void QAbstractSlider::sliderPressed () `[signal]`

This signal is emitted when the user presses the slider with the mouse.

### void QAbstractSlider::sliderReleased () `[signal]`

This signal is emitted when the user releases the slider with the mouse.

### void QAbstractSlider::triggerAction ( SliderAction action )

Triggers a slider action. Possible actions are `SliderSingleStepAdd`, `SliderSingleStepSub`, `SliderPageStepAdd`, `SliderPageStepSub`, `SliderToMinimum`, `SliderToMaximum`, and `SliderMove`.

See also actionTriggered().

### void QAbstractSlider::valueChanged ( int value ) `[signal]`

This signal is emitted when the slider value has changed, with the new slider value as argument.