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Class UIManager

java.lang.Object

javax.swing.UIManager

All Implemented Interfaces:: Serializable

public class UIManager extends Object implements Serializable

UIManager manages the current look and feel, the set of available look and feels, PropertyChangeListeners that are notified when the look and feel changes, look and feel defaults, and convenience methods for obtaining various default values.

Specifying the look and feel

The look and feel can be specified in two distinct ways: by specifying the fully qualified name of the class for the look and feel, or by creating an instance of LookAndFeel and passing it to setLookAndFeel. The following example illustrates setting the look and feel to the system look and feel:

   UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

The following example illustrates setting the look and feel based on class name:

   UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");

Once the look and feel has been changed it is imperative to invoke updateUI on all JComponents. The method SwingUtilities.updateComponentTreeUI(java.awt.Component) makes it easy to apply


 updateUI

to a containment hierarchy. Refer to it for details. The exact behavior of not invoking


 updateUI

after changing the look and feel is unspecified. It is very possible to receive unexpected exceptions, painting problems, or worse.

Default look and feel

The class used for the default look and feel is chosen in the following manner:

If the system property swing.defaultlaf is non-null, use its value as the default look and feel class name.
If the Properties file swing.properties exists and contains the key swing.defaultlaf, use its value as the default look and feel class name. The location that is checked for swing.properties may vary depending upon the implementation of the Java platform. Typically the swing.properties file is located in the conf subdirectory of the Java installation directory. Refer to the release notes of the implementation being used for further details.
Otherwise use the cross platform look and feel.

Defaults

UIManager manages three sets of UIDefaults. In order, they are:

Developer defaults. With few exceptions Swing does not alter the developer defaults; these are intended to be modified and used by the developer.
Look and feel defaults. The look and feel defaults are supplied by the look and feel at the time it is installed as the current look and feel (setLookAndFeel() is invoked). The look and feel defaults can be obtained using the getLookAndFeelDefaults() method.
System defaults. The system defaults are provided by Swing.

Invoking any of the various get methods results in checking each of the defaults, in order, returning the first non-null value. For example, invoking UIManager.getString("Table.foreground") results in first checking developer defaults. If the developer defaults contain a value for "Table.foreground" it is returned, otherwise the look and feel defaults are checked, followed by the system defaults.

It's important to note that getDefaults returns a custom instance of UIDefaults with this resolution logic built into it. For example, UIManager.getDefaults().getString("Table.foreground") is equivalent to UIManager.getString("Table.foreground"). Both resolve using the algorithm just described. In many places the documentation uses the word defaults to refer to the custom instance of UIDefaults with the resolution logic as previously described.

When the look and feel is changed, UIManager alters only the look and feel defaults; the developer and system defaults are not altered by the UIManager in any way.

The set of defaults a particular look and feel supports is defined and documented by that look and feel. In addition, each look and feel, or ComponentUI provided by a look and feel, may access the defaults at different times in their life cycle. Some look and feels may aggressively look up defaults, so that changing a default may not have an effect after installing the look and feel. Other look and feels may lazily access defaults so that a change to the defaults may effect an existing look and feel. Finally, other look and feels might not configure themselves from the defaults table in any way. None-the-less it is usually the case that a look and feel expects certain defaults, so that in general a ComponentUI provided by one look and feel will not work with another look and feel.

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 JavaBeans has been added to the java.beans package. Please see XMLEncoder.

Since:: 1.2

Nested Class Summary

Modifier and Type	Class	Description
`static class`	`UIManager.LookAndFeelInfo`	Provides a little information about an installed `LookAndFeel` for the sake of configuring a menu or for initial application set up.

Constructor Summary

Constructor	Description
`UIManager()`	Constructs a `UIManager`.

Method Summary

Modifier and Type	Method	Description
`static void`	`addAuxiliaryLookAndFeel(LookAndFeel laf)`	Adds a `LookAndFeel` to the list of auxiliary look and feels.
`static void`	`addPropertyChangeListener(PropertyChangeListener listener)`	Adds a `PropertyChangeListener` to the listener list.
`static LookAndFeel`	`createLookAndFeel(String name)`	Creates a supported built-in Java `LookAndFeel` specified by the given `L&F name` name.
`static Object`	`get(Object key)`	Returns an object from the defaults.
`static Object`	`get(Object key, Locale l)`	Returns an object from the defaults that is appropriate for the given locale.
`static LookAndFeel[]`	`getAuxiliaryLookAndFeels()`	Returns the list of auxiliary look and feels (can be `null`).
`static boolean`	`getBoolean(Object key)`	Returns a boolean from the defaults which is associated with the key value.
`static boolean`	`getBoolean(Object key, Locale l)`	Returns a boolean from the defaults which is associated with the key value and the given `Locale`.
`static Border`	`getBorder(Object key)`	Returns a border from the defaults.
`static Border`	`getBorder(Object key, Locale l)`	Returns a border from the defaults that is appropriate for the given locale.
`static Color`	`getColor(Object key)`	Returns a color from the defaults.
`static Color`	`getColor(Object key, Locale l)`	Returns a color from the defaults that is appropriate for the given locale.
`static String`	`getCrossPlatformLookAndFeelClassName()`	Returns the name of the `LookAndFeel` class that implements the default cross platform look and feel -- the Java Look and Feel (JLF).
`static UIDefaults`	`getDefaults()`	Returns the defaults.
`static Dimension`	`getDimension(Object key)`	Returns a dimension from the defaults.
`static Dimension`	`getDimension(Object key, Locale l)`	Returns a dimension from the defaults that is appropriate for the given locale.
`static Font`	`getFont(Object key)`	Returns a font from the defaults.
`static Font`	`getFont(Object key, Locale l)`	Returns a font from the defaults that is appropriate for the given locale.
`static Icon`	`getIcon(Object key)`	Returns an `Icon` from the defaults.
`static Icon`	`getIcon(Object key, Locale l)`	Returns an `Icon` from the defaults that is appropriate for the given locale.
`static Insets`	`getInsets(Object key)`	Returns an `Insets` object from the defaults.
`static Insets`	`getInsets(Object key, Locale l)`	Returns an `Insets` object from the defaults that is appropriate for the given locale.
`static UIManager.LookAndFeelInfo[]`	`getInstalledLookAndFeels()`	Returns an array of `LookAndFeelInfo`s representing the `LookAndFeel` implementations currently available.
`static int`	`getInt(Object key)`	Returns an integer from the defaults.
`static int`	`getInt(Object key, Locale l)`	Returns an integer from the defaults that is appropriate for the given locale.
`static LookAndFeel`	`getLookAndFeel()`	Returns the current look and feel or `null`.
`static UIDefaults`	`getLookAndFeelDefaults()`	Returns the `UIDefaults` from the current look and feel, that were obtained at the time the look and feel was installed.
`static PropertyChangeListener[]`	`getPropertyChangeListeners()`	Returns an array of all the `PropertyChangeListener`s added to this UIManager with addPropertyChangeListener().
`static String`	`getString(Object key)`	Returns a string from the defaults.
`static String`	`getString(Object key, Locale l)`	Returns a string from the defaults that is appropriate for the given locale.
`static String`	`getSystemLookAndFeelClassName()`	Returns the name of the `LookAndFeel` class that implements the native system look and feel if there is one, otherwise the name of the default cross platform `LookAndFeel` class.
`static ComponentUI`	`getUI(JComponent target)`	Returns the appropriate `ComponentUI` implementation for `target`.
`static void`	`installLookAndFeel(String name, String className)`	Adds the specified look and feel to the set of available look and feels.
`static void`	`installLookAndFeel(UIManager.LookAndFeelInfo info)`	Adds the specified look and feel to the set of available look and feels.
`static Object`	`put(Object key, Object value)`	Stores an object in the developer defaults.
`static boolean`	`removeAuxiliaryLookAndFeel(LookAndFeel laf)`	Removes a `LookAndFeel` from the list of auxiliary look and feels.
`static void`	`removePropertyChangeListener(PropertyChangeListener listener)`	Removes a `PropertyChangeListener` from the listener list.
`static void`	`setInstalledLookAndFeels(UIManager.LookAndFeelInfo[] infos)`	Sets the set of available look and feels.
`static void`	`setLookAndFeel(String className)`	Loads the `LookAndFeel` specified by the given class name, using the current thread's context class loader, and passes it to `setLookAndFeel(LookAndFeel)`.
`static void`	`setLookAndFeel(LookAndFeel newLookAndFeel)`	Sets the current look and feel to `newLookAndFeel`.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

UIManager

public UIManager()

Constructs a UIManager.

Method Details

getInstalledLookAndFeels

public static UIManager.LookAndFeelInfo[] getInstalledLookAndFeels()

Returns an array of LookAndFeelInfos representing the LookAndFeel implementations currently available. The LookAndFeelInfo objects can be used by an application to construct a menu of look and feel options for the user, or to determine which look and feel to set at startup time. To avoid the penalty of creating numerous


 LookAndFeel

objects, LookAndFeelInfo maintains the class name of the LookAndFeel class, not the actual LookAndFeel instance.

The following example illustrates setting the current look and feel from an instance of LookAndFeelInfo:

   UIManager.setLookAndFeel(info.getClassName());

Returns:

an array of LookAndFeelInfo objects

See Also:

setInstalledLookAndFeels

public static void setInstalledLookAndFeels(UIManager.LookAndFeelInfo[] infos) throws SecurityException

Sets the set of available look and feels. While this method does not check to ensure all of the LookAndFeelInfos are non-null, it is strongly recommended that only non-null values are supplied in the infos array.

Parameters:

infos - set of LookAndFeelInfo objects specifying the available look and feels

Throws:

NullPointerException - if infos is null

SecurityException

See Also:

installLookAndFeel

public static void installLookAndFeel(UIManager.LookAndFeelInfo info)

Adds the specified look and feel to the set of available look and feels. While this method allows a null info, it is strongly recommended that a non-null value be used.

Parameters:

info - a LookAndFeelInfo object that names the look and feel and identifies the class that implements it

See Also:

installLookAndFeel

public static void installLookAndFeel(String name, String className)

Adds the specified look and feel to the set of available look and feels. While this method does not check the arguments in any way, it is strongly recommended that


 non-null

values be supplied.

Parameters:

name - descriptive name of the look and feel

className - name of the class that implements the look and feel

See Also:

getLookAndFeel

public static LookAndFeel getLookAndFeel()

Returns the current look and feel or null.

Returns:

current look and feel, or null

See Also:

createLookAndFeel

public static LookAndFeel createLookAndFeel(String name) throws UnsupportedLookAndFeelException

Creates a supported built-in Java LookAndFeel specified by the given L&F name name.

Parameters:

name - a String specifying the name of the built-in look and feel

Returns:

the built-in LookAndFeel object

Throws:

NullPointerException - if name is null

UnsupportedLookAndFeelException - if the built-in Java L&F is not found for the given name or it is not supported by the underlying platform

Since:

See Also:

setLookAndFeel

public static void setLookAndFeel(LookAndFeel newLookAndFeel) throws UnsupportedLookAndFeelException

Sets the current look and feel to newLookAndFeel. If the current look and feel is non-null


 uninitialize

is invoked on it. If newLookAndFeel is non-null, initialize is invoked on it followed by getDefaults. The defaults returned from


 newLookAndFeel.getDefaults()

replace those of the defaults from the previous look and feel. If the newLookAndFeel is null, the look and feel defaults are set to null.

A value of null can be used to set the look and feel to null. As the LookAndFeel is required for most of Swing to function, setting the LookAndFeel to null is strongly discouraged.

This is a JavaBeans bound property.

Parameters:

newLookAndFeel - LookAndFeel to install

Throws:

UnsupportedLookAndFeelException - if newLookAndFeel is non-null and newLookAndFeel.isSupportedLookAndFeel() returns false

See Also:

setLookAndFeel

public static void setLookAndFeel(String className) throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException

Loads the LookAndFeel specified by the given class name, using the current thread's context class loader, and passes it to setLookAndFeel(LookAndFeel).

Parameters:: className - a string specifying the name of the class that implements the look and feel
Throws:: ClassNotFoundException - if the LookAndFeel class could not be found; InstantiationException - if a new instance of the class couldn't be created; IllegalAccessException - if the class or initializer isn't accessible; UnsupportedLookAndFeelException - if lnf.isSupportedLookAndFeel() is false; ClassCastException - if className does not identify a class that extends LookAndFeel; NullPointerException - if className is null

getSystemLookAndFeelClassName

public static String getSystemLookAndFeelClassName()

Returns the name of the LookAndFeel class that implements the native system look and feel if there is one, otherwise the name of the default cross platform LookAndFeel class. This value can be overridden by setting the swing.systemlaf system property.

Returns:

the String of the LookAndFeel class

See Also:

getCrossPlatformLookAndFeelClassName

public static String getCrossPlatformLookAndFeelClassName()

Returns the name of the LookAndFeel class that implements the default cross platform look and feel -- the Java Look and Feel (JLF). This value can be overridden by setting the swing.crossplatformlaf system property.

Returns:

a string with the JLF implementation-class

See Also:

getDefaults

public static UIDefaults getDefaults()

Returns the defaults. The returned defaults resolve using the logic specified in the class documentation.

Returns:: a UIDefaults object containing the default values

getFont

public static Font getFont(Object key)

Returns a font from the defaults. If the value for key is not a Font, null is returned.

Parameters:: key - an Object specifying the font
Returns:: the Font object
Throws:: NullPointerException - if key is null

getFont

public static Font getFont(Object key, Locale l)

Returns a font from the defaults that is appropriate for the given locale. If the value for key is not a Font, null is returned.

Parameters:: key - an Object specifying the font; l - the Locale for which the font is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Font object
Throws:: NullPointerException - if key is null
Since:: 1.4

getColor

public static Color getColor(Object key)

Returns a color from the defaults. If the value for key is not a Color, null is returned.

Parameters:: key - an Object specifying the color
Returns:: the Color object
Throws:: NullPointerException - if key is null

getColor

public static Color getColor(Object key, Locale l)

Returns a color from the defaults that is appropriate for the given locale. If the value for key is not a Color, null is returned.

Parameters:: key - an Object specifying the color; l - the Locale for which the color is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Color object
Throws:: NullPointerException - if key is null
Since:: 1.4

getIcon

public static Icon getIcon(Object key)

Returns an Icon from the defaults. If the value for key is not an Icon, null is returned.

Parameters:: key - an Object specifying the icon
Returns:: the Icon object
Throws:: NullPointerException - if key is null

getIcon

public static Icon getIcon(Object key, Locale l)

Returns an Icon from the defaults that is appropriate for the given locale. If the value for key is not an Icon, null is returned.

Parameters:: key - an Object specifying the icon; l - the Locale for which the icon is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Icon object
Throws:: NullPointerException - if key is null
Since:: 1.4

getBorder

public static Border getBorder(Object key)

Returns a border from the defaults. If the value for key is not a Border, null is returned.

Parameters:: key - an Object specifying the border
Returns:: the Border object
Throws:: NullPointerException - if key is null

getBorder

public static Border getBorder(Object key, Locale l)

Returns a border from the defaults that is appropriate for the given locale. If the value for key is not a Border, null is returned.

Parameters:: key - an Object specifying the border; l - the Locale for which the border is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Border object
Throws:: NullPointerException - if key is null
Since:: 1.4

getString

public static String getString(Object key)

Returns a string from the defaults. If the value for key is not a String, null is returned.

Parameters:: key - an Object specifying the string
Returns:: the String
Throws:: NullPointerException - if key is null

getString

public static String getString(Object key, Locale l)

Returns a string from the defaults that is appropriate for the given locale. If the value for key is not a String, null is returned.

Parameters:: key - an Object specifying the string; l - the Locale for which the string is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the String
Throws:: NullPointerException - if key is null
Since:: 1.4

getInt

public static int getInt(Object key)

Returns an integer from the defaults. If the value for key is not an Integer, or does not exist, 0 is returned.

Parameters:: key - an Object specifying the int
Returns:: the int
Throws:: NullPointerException - if key is null

getInt

public static int getInt(Object key, Locale l)

Returns an integer from the defaults that is appropriate for the given locale. If the value for key is not an Integer, or does not exist, 0 is returned.

Parameters:: key - an Object specifying the int; l - the Locale for which the int is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the int
Throws:: NullPointerException - if key is null
Since:: 1.4

getBoolean

public static boolean getBoolean(Object key)

Returns a boolean from the defaults which is associated with the key value. If the key is not found or the key doesn't represent a boolean value then false is returned.

Parameters:: key - an Object specifying the key for the desired boolean value
Returns:: the boolean value corresponding to the key
Throws:: NullPointerException - if key is null
Since:: 1.4

getBoolean

public static boolean getBoolean(Object key, Locale l)

Returns a boolean from the defaults which is associated with the key value and the given Locale. If the key is not found or the key doesn't represent a boolean value then false will be returned.

Parameters:: key - an Object specifying the key for the desired boolean value; l - the Locale for which the boolean is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the boolean value corresponding to the key
Throws:: NullPointerException - if key is null
Since:: 1.4

getInsets

public static Insets getInsets(Object key)

Returns an Insets object from the defaults. If the value for key is not an Insets, null is returned.

Parameters:: key - an Object specifying the Insets object
Returns:: the Insets object
Throws:: NullPointerException - if key is null

getInsets

public static Insets getInsets(Object key, Locale l)

Returns an Insets object from the defaults that is appropriate for the given locale. If the value for key is not an Insets, null is returned.

Parameters:: key - an Object specifying the Insets object; l - the Locale for which the object is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Insets object
Throws:: NullPointerException - if key is null
Since:: 1.4

getDimension

public static Dimension getDimension(Object key)

Returns a dimension from the defaults. If the value for key is not a Dimension, null is returned.

Parameters:: key - an Object specifying the dimension object
Returns:: the Dimension object
Throws:: NullPointerException - if key is null

getDimension

public static Dimension getDimension(Object key, Locale l)

Returns a dimension from the defaults that is appropriate for the given locale. If the value for key is not a Dimension, null is returned.

Parameters:: key - an Object specifying the dimension object; l - the Locale for which the object is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Dimension object
Throws:: NullPointerException - if key is null
Since:: 1.4

get

public static Object get(Object key)

Returns an object from the defaults.

Parameters:: key - an Object specifying the desired object
Returns:: the Object
Throws:: NullPointerException - if key is null

get

public static Object get(Object key, Locale l)

Returns an object from the defaults that is appropriate for the given locale.

Parameters:: key - an Object specifying the desired object; l - the Locale for which the object is desired; refer to UIDefaults for details on how a null Locale is handled
Returns:: the Object
Throws:: NullPointerException - if key is null
Since:: 1.4

put

public static Object put(Object key, Object value)

Stores an object in the developer defaults. This is a cover method for getDefaults().put(key, value). This only effects the developer defaults, not the system or look and feel defaults.

Parameters:

key - an Object specifying the retrieval key

value - the Object to store; refer to UIDefaults for details on how null is handled

Returns:

the Object returned by UIDefaults.put(java.lang.Object, java.lang.Object)

Throws:

NullPointerException - if key is null

See Also:

getUI

public static ComponentUI getUI(JComponent target)

Returns the appropriate ComponentUI implementation for target. Typically, this is a cover for getDefaults().getUI(target). However, if an auxiliary look and feel has been installed, this first invokes getUI(target) on the multiplexing look and feel's defaults, and returns that value if it is non-null.

Parameters:

target - the JComponent to return the ComponentUI for

Returns:

the ComponentUI object for target

Throws:

NullPointerException - if target is null

See Also:

getLookAndFeelDefaults

public static UIDefaults getLookAndFeelDefaults()

Returns the UIDefaults from the current look and feel, that were obtained at the time the look and feel was installed.

In general, developers should use the UIDefaults returned from getDefaults(). As the current look and feel may expect certain values to exist, altering the UIDefaults returned from this method could have unexpected results.

Returns:

UIDefaults from the current look and feel

See Also:

addAuxiliaryLookAndFeel

public static void addAuxiliaryLookAndFeel(LookAndFeel laf)

Adds a LookAndFeel to the list of auxiliary look and feels. The auxiliary look and feels tell the multiplexing look and feel what other LookAndFeel classes for a component instance are to be used in addition to the default LookAndFeel class when creating a multiplexing UI. The change will only take effect when a new UI class is created or when the default look and feel is changed on a component instance.

Note these are not the same as the installed look and feels.

Parameters:

laf - the LookAndFeel object

See Also:

removeAuxiliaryLookAndFeel

public static boolean removeAuxiliaryLookAndFeel(LookAndFeel laf)

Removes a LookAndFeel from the list of auxiliary look and feels. The auxiliary look and feels tell the multiplexing look and feel what other LookAndFeel classes for a component instance are to be used in addition to the default LookAndFeel class when creating a multiplexing UI. The change will only take effect when a new UI class is created or when the default look and feel is changed on a component instance.

Note these are not the same as the installed look and feels.

Parameters:

laf - the LookAndFeel to be removed

Returns:

true if the LookAndFeel was removed from the list

See Also:

getAuxiliaryLookAndFeels

public static LookAndFeel[] getAuxiliaryLookAndFeels()

Returns the list of auxiliary look and feels (can be null). The auxiliary look and feels tell the multiplexing look and feel what other LookAndFeel classes for a component instance are to be used in addition to the default LookAndFeel class when creating a multiplexing UI.

Note these are not the same as the installed look and feels.

Returns:

list of auxiliary LookAndFeels or null

See Also:

addPropertyChangeListener

public static void addPropertyChangeListener(PropertyChangeListener listener)

Adds a PropertyChangeListener to the listener list. The listener is registered for all properties.

Parameters:

listener - the PropertyChangeListener to be added

See Also:

removePropertyChangeListener

public static void removePropertyChangeListener(PropertyChangeListener listener)

Removes a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties.

Parameters:

listener - the PropertyChangeListener to be removed

See Also:

getPropertyChangeListeners

public static PropertyChangeListener[] getPropertyChangeListeners()

Returns an array of all the PropertyChangeListeners added to this UIManager with addPropertyChangeListener().

Returns:: all of the PropertyChangeListeners added or an empty array if no listeners have been added
Since:: 1.4

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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/swing/UIManager.html