public class

JSlider

extends JComponent
implements Accessible SwingConstants
java.lang.Object
   ↳ java.awt.Component
     ↳ java.awt.Container
       ↳ javax.swing.JComponent
         ↳ javax.swing.JSlider

Class Overview

A component that lets the user graphically select a value by sliding a knob within a bounded interval.

The slider can show both major tick marks, and minor tick marks between the major ones. The number of values between the tick marks is controlled with setMajorTickSpacing and setMinorTickSpacing. Painting of tick marks is controlled by setPaintTicks.

Sliders can also print text labels at regular intervals (or at arbitrary locations) along the slider track. Painting of labels is controlled by setLabelTable and setPaintLabels.

For further information and examples see How to Use Sliders, a section in The Java Tutorial.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.

Summary

Nested Classes
class JSlider.AccessibleJSlider This class implements accessibility support for the JSlider class. 
[Expand]
Inherited Constants
From class javax.swing.JComponent
From class java.awt.Component
From interface java.awt.image.ImageObserver
From interface javax.swing.SwingConstants
Fields
protected ChangeEvent changeEvent Only one ChangeEvent is needed per slider instance since the event's only (read-only) state is the source property.
protected ChangeListener changeListener The changeListener (no suffix) is the listener we add to the slider's model.
protected int majorTickSpacing The number of values between the major tick marks -- the larger marks that break up the minor tick marks.
protected int minorTickSpacing The number of values between the minor tick marks -- the smaller marks that occur between the major tick marks.
protected int orientation Whether the slider is horizontal or vertical The default is horizontal.
protected BoundedRangeModel sliderModel The data model that handles the numeric maximum value, minimum value, and current-position value for the slider.
protected boolean snapToTicks If true, the knob (and the data value it represents) resolve to the closest tick mark next to where the user positioned the knob.
[Expand]
Inherited Fields
From class javax.swing.JComponent
Public Constructors
JSlider()
Creates a horizontal slider with the range 0 to 100 and an initial value of 50.
JSlider(int orientation)
Creates a slider using the specified orientation with the range 0 to 100 and an initial value of 50.
JSlider(int min, int max)
Creates a horizontal slider using the specified min and max with an initial value equal to the average of the min plus max.
JSlider(int min, int max, int value)
Creates a horizontal slider using the specified min, max and value.
JSlider(int orientation, int min, int max, int value)
Creates a slider with the specified orientation and the specified minimum, maximum, and initial values.
JSlider(BoundedRangeModel brm)
Creates a horizontal slider using the specified BoundedRangeModel.
Public Methods
void addChangeListener(ChangeListener l)
Adds a ChangeListener to the slider.
Hashtable createStandardLabels(int increment)
Creates a Hashtable of numerical text labels, starting at the slider minimum, and using the increment specified.
Hashtable createStandardLabels(int increment, int start)
Creates a Hashtable of numerical text labels, starting at the starting point specified, and using the increment specified.
AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this JSlider.
ChangeListener[] getChangeListeners()
Returns an array of all the ChangeListeners added to this JSlider with addChangeListener().
int getExtent()
Returns the "extent" from the BoundedRangeModel.
boolean getInverted()
Returns true if the value-range shown for the slider is reversed,
Dictionary getLabelTable()
Returns the dictionary of what labels to draw at which values.
int getMajorTickSpacing()
This method returns the major tick spacing.
int getMaximum()
Returns the maximum value supported by the slider from the BoundedRangeModel.
int getMinimum()
Returns the minimum value supported by the slider from the BoundedRangeModel.
int getMinorTickSpacing()
This method returns the minor tick spacing.
BoundedRangeModel getModel()
Returns the BoundedRangeModel that handles the slider's three fundamental properties: minimum, maximum, value.
int getOrientation()
Return this slider's vertical or horizontal orientation.
boolean getPaintLabels()
Tells if labels are to be painted.
boolean getPaintTicks()
Tells if tick marks are to be painted.
boolean getPaintTrack()
Tells if the track (area the slider slides in) is to be painted.
boolean getSnapToTicks()
Returns true if the knob (and the data value it represents) resolve to the closest tick mark next to where the user positioned the knob.
SliderUI getUI()
Gets the UI object which implements the L&F for this component.
String getUIClassID()
Returns the name of the L&F class that renders this component.
int getValue()
Returns the slider's current value from the BoundedRangeModel.
boolean getValueIsAdjusting()
Returns the valueIsAdjusting property from the model.
void removeChangeListener(ChangeListener l)
Removes a ChangeListener from the slider.
void setExtent(int extent)
Sets the size of the range "covered" by the knob.
void setFont(Font font)
Sets the font for this component.
void setInverted(boolean b)
Specify true to reverse the value-range shown for the slider and false to put the value range in the normal order.
void setLabelTable(Dictionary labels)
Used to specify what label will be drawn at any given value.
void setMajorTickSpacing(int n)
This method sets the major tick spacing.
void setMaximum(int maximum)
Sets the slider's maximum value to maximum.
void setMinimum(int minimum)
Sets the slider's minimum value to minimum.
void setMinorTickSpacing(int n)
This method sets the minor tick spacing.
void setModel(BoundedRangeModel newModel)
Sets the BoundedRangeModel that handles the slider's three fundamental properties: minimum, maximum, value.
void setOrientation(int orientation)
Set the slider's orientation to either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.
void setPaintLabels(boolean b)
Determines whether labels are painted on the slider.
void setPaintTicks(boolean b)
Determines whether tick marks are painted on the slider.
void setPaintTrack(boolean b)
Determines whether the track is painted on the slider.
void setSnapToTicks(boolean b)
Specifying true makes the knob (and the data value it represents) resolve to the closest tick mark next to where the user positioned the knob.
void setUI(SliderUI ui)
Sets the UI object which implements the L&F for this component.
void setValue(int n)
Sets the slider's current value to n.
void setValueIsAdjusting(boolean b)
Sets the model's valueIsAdjusting property.
void updateUI()
Resets the UI property to a value from the current look and feel.
Protected Methods
ChangeListener createChangeListener()
Subclasses that want to handle ChangeEvents from the model differently can override this to return an instance of a custom ChangeListener implementation.
void fireStateChanged()
Send a ChangeEvent, whose source is this JSlider, to all ChangeListeners that have registered interest in ChangeEvents.
String paramString()
Returns a string representation of this JSlider.
void updateLabelUIs()
Updates the UIs for the labels in the label table by calling updateUI on each label.
[Expand]
Inherited Methods
From class javax.swing.JComponent
From class java.awt.Container
From class java.awt.Component
From class java.lang.Object
From interface java.awt.MenuContainer
From interface java.awt.image.ImageObserver
From interface javax.accessibility.Accessible

Fields

protected ChangeEvent changeEvent

Only one ChangeEvent is needed per slider instance since the event's only (read-only) state is the source property. The source of events generated here is always "this". The event is lazily created the first time that an event notification is fired.

protected ChangeListener changeListener

The changeListener (no suffix) is the listener we add to the slider's model. This listener is initialized to the ChangeListener returned from createChangeListener, which by default just forwards events to ChangeListeners (if any) added directly to the slider.

protected int majorTickSpacing

The number of values between the major tick marks -- the larger marks that break up the minor tick marks.

protected int minorTickSpacing

The number of values between the minor tick marks -- the smaller marks that occur between the major tick marks.

protected int orientation

Whether the slider is horizontal or vertical The default is horizontal.

protected BoundedRangeModel sliderModel

The data model that handles the numeric maximum value, minimum value, and current-position value for the slider.

protected boolean snapToTicks

If true, the knob (and the data value it represents) resolve to the closest tick mark next to where the user positioned the knob. The default is false.

Public Constructors

public JSlider ()

Creates a horizontal slider with the range 0 to 100 and an initial value of 50.

public JSlider (int orientation)

Creates a slider using the specified orientation with the range 0 to 100 and an initial value of 50. The orientation can be either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.

Parameters
orientation the orientation of the slider
Throws
IllegalArgumentException if orientation is not one of VERTICAL, HORIZONTAL

public JSlider (int min, int max)

Creates a horizontal slider using the specified min and max with an initial value equal to the average of the min plus max.

The BoundedRangeModel that holds the slider's data handles any issues that may arise from improperly setting the minimum and maximum values on the slider. See the BoundedRangeModel documentation for details.

Parameters
min the minimum value of the slider
max the maximum value of the slider

public JSlider (int min, int max, int value)

Creates a horizontal slider using the specified min, max and value.

The BoundedRangeModel that holds the slider's data handles any issues that may arise from improperly setting the minimum, initial, and maximum values on the slider. See the BoundedRangeModel documentation for details.

Parameters
min the minimum value of the slider
max the maximum value of the slider
value the initial value of the slider

public JSlider (int orientation, int min, int max, int value)

Creates a slider with the specified orientation and the specified minimum, maximum, and initial values. The orientation can be either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.

The BoundedRangeModel that holds the slider's data handles any issues that may arise from improperly setting the minimum, initial, and maximum values on the slider. See the BoundedRangeModel documentation for details.

Parameters
orientation the orientation of the slider
min the minimum value of the slider
max the maximum value of the slider
value the initial value of the slider
Throws
IllegalArgumentException if orientation is not one of VERTICAL, HORIZONTAL

public JSlider (BoundedRangeModel brm)

Creates a horizontal slider using the specified BoundedRangeModel.

Public Methods

public void addChangeListener (ChangeListener l)

Adds a ChangeListener to the slider.

Parameters
l the ChangeListener to add

public Hashtable createStandardLabels (int increment)

Creates a Hashtable of numerical text labels, starting at the slider minimum, and using the increment specified. For example, if you call createStandardLabels( 10 ) and the slider minimum is zero, then labels will be created for the values 0, 10, 20, 30, and so on.

For the labels to be drawn on the slider, the returned Hashtable must be passed into setLabelTable, and setPaintLabels must be set to true.

For further details on the makeup of the returned Hashtable, see the setLabelTable documentation.

Parameters
increment distance between labels in the generated hashtable
Returns
  • a new Hashtable of labels
Throws
IllegalArgumentException if increment is less than or equal to zero

public Hashtable createStandardLabels (int increment, int start)

Creates a Hashtable of numerical text labels, starting at the starting point specified, and using the increment specified. For example, if you call createStandardLabels( 10, 2 ), then labels will be created for the values 2, 12, 22, 32, and so on.

For the labels to be drawn on the slider, the returned Hashtable must be passed into setLabelTable, and setPaintLabels must be set to true.

For further details on the makeup of the returned Hashtable, see the setLabelTable documentation.

Parameters
increment distance between labels in the generated hashtable
start value at which the labels will begin
Returns
  • a new Hashtable of labels
Throws
IllegalArgumentException if start is out of range, or if increment is less than or equal to zero

public AccessibleContext getAccessibleContext ()

Gets the AccessibleContext associated with this JSlider. For sliders, the AccessibleContext takes the form of an AccessibleJSlider. A new AccessibleJSlider instance is created if necessary.

Returns
  • an AccessibleJSlider that serves as the AccessibleContext of this JSlider

public ChangeListener[] getChangeListeners ()

Returns an array of all the ChangeListeners added to this JSlider with addChangeListener().

Returns
  • all of the ChangeListeners added or an empty array if no listeners have been added

public int getExtent ()

Returns the "extent" from the BoundedRangeModel. This respresents the range of values "covered" by the knob.

Returns
  • an int representing the extent

public boolean getInverted ()

Returns true if the value-range shown for the slider is reversed,

Returns
  • true if the slider values are reversed from their normal order

public Dictionary getLabelTable ()

Returns the dictionary of what labels to draw at which values.

Returns
  • the Dictionary containing labels and where to draw them

public int getMajorTickSpacing ()

This method returns the major tick spacing. The number that is returned represents the distance, measured in values, between each major tick mark. If you have a slider with a range from 0 to 50 and the major tick spacing is set to 10, you will get major ticks next to the following values: 0, 10, 20, 30, 40, 50.

Returns
  • the number of values between major ticks

public int getMaximum ()

Returns the maximum value supported by the slider from the BoundedRangeModel.

Returns
  • the value of the model's maximum property

public int getMinimum ()

Returns the minimum value supported by the slider from the BoundedRangeModel.

Returns
  • the value of the model's minimum property

public int getMinorTickSpacing ()

This method returns the minor tick spacing. The number that is returned represents the distance, measured in values, between each minor tick mark. If you have a slider with a range from 0 to 50 and the minor tick spacing is set to 10, you will get minor ticks next to the following values: 0, 10, 20, 30, 40, 50.

Returns
  • the number of values between minor ticks

public BoundedRangeModel getModel ()

Returns the BoundedRangeModel that handles the slider's three fundamental properties: minimum, maximum, value.

Returns
  • the data model for this component

public int getOrientation ()

Return this slider's vertical or horizontal orientation.

Returns
  • SwingConstants.VERTICAL or SwingConstants.HORIZONTAL

public boolean getPaintLabels ()

Tells if labels are to be painted.

Returns
  • true if labels are painted, else false

public boolean getPaintTicks ()

Tells if tick marks are to be painted.

Returns
  • true if tick marks are painted, else false

public boolean getPaintTrack ()

Tells if the track (area the slider slides in) is to be painted.

Returns
  • true if track is painted, else false

public boolean getSnapToTicks ()

Returns true if the knob (and the data value it represents) resolve to the closest tick mark next to where the user positioned the knob.

Returns
  • true if the value snaps to the nearest tick mark, else false

public SliderUI getUI ()

Gets the UI object which implements the L&F for this component.

Returns
  • the SliderUI object that implements the Slider L&F

public String getUIClassID ()

Returns the name of the L&F class that renders this component.

Returns
  • "SliderUI"

public int getValue ()

Returns the slider's current value from the BoundedRangeModel.

Returns
  • the current value of the slider

public boolean getValueIsAdjusting ()

Returns the valueIsAdjusting property from the model. For details on how this is used, see the setValueIsAdjusting documentation.

Returns
  • the value of the model's valueIsAdjusting property

public void removeChangeListener (ChangeListener l)

Removes a ChangeListener from the slider.

Parameters
l the ChangeListener to remove

public void setExtent (int extent)

Sets the size of the range "covered" by the knob. Most look and feel implementations will change the value by this amount if the user clicks on either side of the knob. This method just forwards the new extent value to the model.

The data model (an instance of BoundedRangeModel) handles any mathematical issues arising from assigning faulty values. See the BoundedRangeModel documentation for details.

If the new extent value is different from the previous extent value, all change listeners are notified.

Parameters
extent the new extent

public void setFont (Font font)

Sets the font for this component.

Parameters
font the desired Font for this component

public void setInverted (boolean b)

Specify true to reverse the value-range shown for the slider and false to put the value range in the normal order. The order depends on the slider's ComponentOrientation property. Normal (non-inverted) horizontal sliders with a ComponentOrientation value of LEFT_TO_RIGHT have their maximum on the right. Normal horizontal sliders with a ComponentOrientation value of RIGHT_TO_LEFT have their maximum on the left. Normal vertical sliders have their maximum on the top. These labels are reversed when the slider is inverted.

By default, the value of this property is false.

Parameters
b true to reverse the slider values from their normal order

public void setLabelTable (Dictionary labels)

Used to specify what label will be drawn at any given value. The key-value pairs are of this format: { Integer value, java.swing.JComponent label }.

An easy way to generate a standard table of value labels is by using the createStandardLabels method.

Once the labels have been set, this method calls updateLabelUIs(). Note that the labels are only painted if the paintLabels property is true.

Parameters
labels new Dictionary of labels, or null to remove all labels

public void setMajorTickSpacing (int n)

This method sets the major tick spacing. The number that is passed in represents the distance, measured in values, between each major tick mark. If you have a slider with a range from 0 to 50 and the major tick spacing is set to 10, you will get major ticks next to the following values: 0, 10, 20, 30, 40, 50.

In order for major ticks to be painted, setPaintTicks must be set to true.

This method will also set up a label table for you. If there is not already a label table, and the major tick spacing is > 0, and getPaintLabels returns true, a standard label table will be generated (by calling createStandardLabels) with labels at the major tick marks. For the example above, you would get text labels: "0", "10", "20", "30", "40", "50". The label table is then set on the slider by calling setLabelTable.

Parameters
n new value for the majorTickSpacing property

public void setMaximum (int maximum)

Sets the slider's maximum value to maximum. This method forwards the new maximum value to the model.

The data model (an instance of BoundedRangeModel) handles any mathematical issues arising from assigning faulty values. See the BoundedRangeModel documentation for details.

If the new maximum value is different from the previous maximum value, all change listeners are notified.

Parameters
maximum the new maximum

public void setMinimum (int minimum)

Sets the slider's minimum value to minimum. This method forwards the new minimum value to the model.

The data model (an instance of BoundedRangeModel) handles any mathematical issues arising from assigning faulty values. See the BoundedRangeModel documentation for details.

If the new minimum value is different from the previous minimum value, all change listeners are notified.

Parameters
minimum the new minimum

public void setMinorTickSpacing (int n)

This method sets the minor tick spacing. The number that is passed in represents the distance, measured in values, between each minor tick mark. If you have a slider with a range from 0 to 50 and the minor tick spacing is set to 10, you will get minor ticks next to the following values: 0, 10, 20, 30, 40, 50.

In order for minor ticks to be painted, setPaintTicks must be set to true.

Parameters
n new value for the minorTickSpacing property

public void setModel (BoundedRangeModel newModel)

Sets the BoundedRangeModel that handles the slider's three fundamental properties: minimum, maximum, value.

Attempts to pass a null model to this method result in undefined behavior, and, most likely, exceptions.

Parameters
newModel the new, non-null BoundedRangeModel to use

public void setOrientation (int orientation)

Set the slider's orientation to either SwingConstants.VERTICAL or SwingConstants.HORIZONTAL.

Parameters
orientation HORIZONTAL or VERTICAL
Throws
IllegalArgumentException if orientation is not one of VERTICAL, HORIZONTAL
See Also

public void setPaintLabels (boolean b)

Determines whether labels are painted on the slider.

This method will also set up a label table for you. If there is not already a label table, and the major tick spacing is > 0, a standard label table will be generated (by calling createStandardLabels) with labels at the major tick marks. The label table is then set on the slider by calling setLabelTable.

By default, this property is false.

Parameters
b whether or not to paint labels

public void setPaintTicks (boolean b)

Determines whether tick marks are painted on the slider. By default, this property is false.

Parameters
b whether or not tick marks should be painted
See Also

public void setPaintTrack (boolean b)

Determines whether the track is painted on the slider. By default, this property is true.

Parameters
b whether or not to paint the slider track
See Also

public void setSnapToTicks (boolean b)

Specifying true makes the knob (and the data value it represents) resolve to the closest tick mark next to where the user positioned the knob. By default, this property is false.

Parameters
b true to snap the knob to the nearest tick mark
See Also

public void setUI (SliderUI ui)

Sets the UI object which implements the L&F for this component.

Parameters
ui the SliderUI L&F object

public void setValue (int n)

Sets the slider's current value to n. This method forwards the new value to the model.

The data model (an instance of BoundedRangeModel) handles any mathematical issues arising from assigning faulty values. See the BoundedRangeModel documentation for details.

If the new value is different from the previous value, all change listeners are notified.

Parameters
n the new value

public void setValueIsAdjusting (boolean b)

Sets the model's valueIsAdjusting property. Slider look and feel implementations should set this property to true when a knob drag begins, and to false when the drag ends. The slider model will not generate ChangeEvents while valueIsAdjusting is true.

Parameters
b the new value for the valueIsAdjusting property

public void updateUI ()

Resets the UI property to a value from the current look and feel.

See Also

Protected Methods

protected ChangeListener createChangeListener ()

Subclasses that want to handle ChangeEvents from the model differently can override this to return an instance of a custom ChangeListener implementation. The default ChangeListener simply calls the fireStateChanged method to forward ChangeEvents to the ChangeListeners that have been added directly to the slider.

protected void fireStateChanged ()

Send a ChangeEvent, whose source is this JSlider, to all ChangeListeners that have registered interest in ChangeEvents. This method is called each time a ChangeEvent is received from the model.

The event instance is created if necessary, and stored in changeEvent.

protected String paramString ()

Returns a string representation of this JSlider. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Returns
  • a string representation of this JSlider.

protected void updateLabelUIs ()

Updates the UIs for the labels in the label table by calling updateUI on each label. The UIs are updated from the current look and feel. The labels are also set to their preferred size.