OpenJDK 1.22 · javax.swing.plaf.ComponentUI · APIdia, the JavaDoc alternative

Access	Constructor and Description
public	ComponentUI() Sole constructor.

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: `true` if the specified `x,y` location is contained within the look and feel's defined shape for the given component contains(JComponent the component where the x,y location is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c, int the x coordinate of the point x, int the y coordinate of the point y) Returns `true` if the specified x,y location is contained within the look and feel's defined shape of the specified component.
public static ComponentUI	Returns: a `ComponentUI` object for `c` createUI(JComponent a `JComponent` for which to create a UI delegate c) Returns an instance of the UI delegate for the specified component.
public Accessible	Returns: the `i`th `Accessible` child of the object getAccessibleChild(JComponent a `JComponent` for which to get a child object c, int zero-based index of child i) Returns the `i`th `Accessible` child of the object.
public int	Returns: the number of accessible children in the object getAccessibleChildrenCount(JComponent `JComponent` for which to get count of accessible children c) Returns the number of accessible children in the object.
public int	Returns: baseline or a value < 0 indicating there is no reasonable baseline getBaseline(JComponent `JComponent` baseline is being requested for c, int the width to get the baseline for width, int the height to get the baseline for height) Returns the baseline.
public Component.BaselineResizeBehavior	Returns: an enum indicating how the baseline changes as the component size changes getBaselineResizeBehavior(JComponent `JComponent` to return baseline resize behavior for c) Returns an enum indicating how the baseline of the component changes as the size changes.
public Dimension	Returns: a `Dimension` object or `null` getMaximumSize(JComponent the component whose maximum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c) Returns the specified component's maximum size appropriate for the look and feel.
public Dimension	Returns: a `Dimension` object or `null` getMinimumSize(JComponent the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c) Returns the specified component's minimum size appropriate for the look and feel.
public Dimension	Returns: a `Dimension` object containing given component's preferred size appropriate for the look and feel getPreferredSize(JComponent the component whose preferred size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c) Returns the specified component's preferred size appropriate for the look and feel.
public void	installUI(JComponent the component where this UI delegate is being installed c) Configures the specified component appropriately for the look and feel.
public void	paint(Graphics the `Graphics` context in which to paint g, JComponent the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c) Paints the specified component appropriately for the look and feel.
public void	uninstallUI(JComponent the component from which this UI delegate is being removed; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c) Reverses configuration which was done on the specified component during `installUI`.
public void	update(Graphics the `Graphics` context in which to paint g, JComponent the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components c) Notifies this UI delegate that it is time to paint the specified component.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

ComponentUI	back to summary
public ComponentUI() Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

contains back to summary

contains	back to summary
public boolean contains(JComponent c, int x, int y) Returns `true` if the specified x,y location is contained within the look and feel's defined shape of the specified component. `x` and `y` are defined to be relative to the coordinate system of the specified component. Although a component's `bounds` is constrained to a rectangle, this method provides the means for defining a non-rectangular shape within those bounds for the purpose of hit detection. Parameters c:JComponent the component where the x,y location is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components x:int the x coordinate of the point y:int the y coordinate of the point Returns:boolean `true` if the specified `x,y` location is contained within the look and feel's defined shape for the given component Annotations @SuppressWarnings:deprecation See Also `javax.swing.JComponent#contains`, `java.awt.Component#contains`

public boolean contains(JComponent c, int x, int y)

Returns true if the specified x,y location is contained within the look and feel's defined shape of the specified component. x and y are defined to be relative to the coordinate system of the specified component. Although a component's bounds is constrained to a rectangle, this method provides the means for defining a non-rectangular shape within those bounds for the purpose of hit detection.

Parameters

c:JComponent: the component where the x,y location is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
x:int: the x coordinate of the point
y:int: the y coordinate of the point

Returns:boolean

true if the specified x,y location is contained within the look and feel's defined shape for the given component

Annotations

@SuppressWarnings:deprecation

createUI back to summary

createUI	back to summary
public static ComponentUI createUI(JComponent c) Returns an instance of the UI delegate for the specified component. Each subclass must provide its own static `createUI` method that returns an instance of that UI delegate subclass. If the UI delegate subclass is stateless, it may return an instance that is shared by multiple components. If the UI delegate is stateful, then it should return a new instance per component. The default implementation of this method throws an error, as it should never be invoked. Parameters c:JComponent a `JComponent` for which to create a UI delegate Returns:ComponentUI a `ComponentUI` object for `c`

public static ComponentUI createUI(JComponent c)

Returns an instance of the UI delegate for the specified component. Each subclass must provide its own static createUI method that returns an instance of that UI delegate subclass. If the UI delegate subclass is stateless, it may return an instance that is shared by multiple components. If the UI delegate is stateful, then it should return a new instance per component. The default implementation of this method throws an error, as it should never be invoked.

Parameters

c:JComponent: a JComponent for which to create a UI delegate

Returns:ComponentUI

a ComponentUI object for c

getAccessibleChild back to summary

getAccessibleChild	back to summary
public Accessible getAccessibleChild(JComponent c, int i) Returns the `i`th `Accessible` child of the object. UIs might need to override this if they present areas on the screen that can be viewed as components, but actual components are not used for presenting those areas. Note As of v1.3, it is recommended that developers call `Component.AccessibleAWTComponent.getAccessibleChild()` instead of this method. Parameters c:JComponent a `JComponent` for which to get a child object i:int zero-based index of child Returns:Accessible the `i`th `Accessible` child of the object See Also `getAccessibleChildrenCount`

public Accessible getAccessibleChild(JComponent c, int i)

Returns the ith Accessible child of the object. UIs might need to override this if they present areas on the screen that can be viewed as components, but actual components are not used for presenting those areas.

Note

As of v1.3, it is recommended that developers call Component.AccessibleAWTComponent.getAccessibleChild() instead of this method.

Parameters

c:JComponent: a JComponent for which to get a child object
i:int: zero-based index of child

Returns:Accessible

the ith Accessible child of the object

See Also

getAccessibleChildrenCount

getAccessibleChildrenCount back to summary

getAccessibleChildrenCount	back to summary
public int getAccessibleChildrenCount(JComponent c) Returns the number of accessible children in the object. If all of the children of this object implement `Accessible`, this method should return the number of children of this object. UIs might wish to override this if they present areas on the screen that can be viewed as components, but actual components are not used for presenting those areas. Note As of v1.3, it is recommended that developers call `Component.AccessibleAWTComponent.getAccessibleChildrenCount()` instead of this method. Parameters c:JComponent `JComponent` for which to get count of accessible children Returns:int the number of accessible children in the object See Also `getAccessibleChild`

public int getAccessibleChildrenCount(JComponent c)

Returns the number of accessible children in the object. If all of the children of this object implement Accessible, this method should return the number of children of this object. UIs might wish to override this if they present areas on the screen that can be viewed as components, but actual components are not used for presenting those areas.

Note

As of v1.3, it is recommended that developers call Component.AccessibleAWTComponent.getAccessibleChildrenCount() instead of this method.

Parameters

c:JComponent: JComponent for which to get count of accessible children

Returns:int

the number of accessible children in the object

See Also

getAccessibleChild

getBaseline back to summary

getBaseline	back to summary
public int getBaseline(JComponent c, int width, int height) Returns the baseline. The baseline is measured from the top of the component. This method is primarily meant for `LayoutManager`s to align components along their baseline. A return value less than 0 indicates this component does not have a reasonable baseline and that `LayoutManager`s should not align this component on its baseline. This method returns -1. Subclasses that have a meaningful baseline should override appropriately. Parameters c:JComponent `JComponent` baseline is being requested for width:int the width to get the baseline for height:int the height to get the baseline for Returns:int baseline or a value < 0 indicating there is no reasonable baseline Exceptions NullPointerException: if `c` is `null` IllegalArgumentException: if width or height is < 0 Since 1.6 See Also `javax.swing.JComponent#getBaseline(int, int)`

public int getBaseline(JComponent c, int width, int height)

Returns the baseline. The baseline is measured from the top of the component. This method is primarily meant for LayoutManagers to align components along their baseline. A return value less than 0 indicates this component does not have a reasonable baseline and that LayoutManagers should not align this component on its baseline.

This method returns -1. Subclasses that have a meaningful baseline should override appropriately.

Parameters

c:JComponent: JComponent baseline is being requested for
width:int: the width to get the baseline for
height:int: the height to get the baseline for

Returns:int

baseline or a value < 0 indicating there is no reasonable baseline

Exceptions

NullPointerException:: if c is null
IllegalArgumentException:: if width or height is < 0

Since

1.6

getBaselineResizeBehavior back to summary

getBaselineResizeBehavior	back to summary
public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c) Returns an enum indicating how the baseline of the component changes as the size changes. This method is primarily meant for layout managers and GUI builders. This method returns `BaselineResizeBehavior.OTHER`. Subclasses that support a baseline should override appropriately. Parameters c:JComponent `JComponent` to return baseline resize behavior for Returns:Component.BaselineResizeBehavior an enum indicating how the baseline changes as the component size changes Exceptions NullPointerException: if `c` is `null` Since 1.6 See Also `javax.swing.JComponent#getBaseline(int, int)`

public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)

Returns an enum indicating how the baseline of the component changes as the size changes. This method is primarily meant for layout managers and GUI builders.

This method returns BaselineResizeBehavior.OTHER. Subclasses that support a baseline should override appropriately.

Parameters

c:JComponent: JComponent to return baseline resize behavior for

Returns:Component.BaselineResizeBehavior

an enum indicating how the baseline changes as the component size changes

Exceptions

NullPointerException:: if c is null

Since

1.6

getMaximumSize back to summary

getMaximumSize	back to summary
public Dimension getMaximumSize(JComponent c) Returns the specified component's maximum size appropriate for the look and feel. If `null` is returned, the maximum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes `getPreferredSize` and returns that value. Parameters c:JComponent the component whose maximum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components Returns:Dimension a `Dimension` object or `null` See Also `javax.swing.JComponent#getMaximumSize`, `java.awt.LayoutManager2#maximumLayoutSize`

public Dimension getMaximumSize(JComponent c)

Returns the specified component's maximum size appropriate for the look and feel. If null is returned, the maximum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes getPreferredSize and returns that value.

Parameters

c:JComponent: the component whose maximum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

Returns:Dimension

a Dimension object or null

getMinimumSize back to summary

getMinimumSize	back to summary
public Dimension getMinimumSize(JComponent c) Returns the specified component's minimum size appropriate for the look and feel. If `null` is returned, the minimum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes `getPreferredSize` and returns that value. Parameters c:JComponent the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components Returns:Dimension a `Dimension` object or `null` See Also `javax.swing.JComponent#getMinimumSize`, `java.awt.LayoutManager#minimumLayoutSize`, `getPreferredSize`

public Dimension getMinimumSize(JComponent c)

Returns the specified component's minimum size appropriate for the look and feel. If null is returned, the minimum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes getPreferredSize and returns that value.

Parameters

c:JComponent: the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

Returns:Dimension

a Dimension object or null

getPreferredSize back to summary

getPreferredSize	back to summary
public Dimension getPreferredSize(JComponent c) Returns the specified component's preferred size appropriate for the look and feel. If `null` is returned, the preferred size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method returns `null`. Parameters c:JComponent the component whose preferred size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components Returns:Dimension a `Dimension` object containing given component's preferred size appropriate for the look and feel See Also `javax.swing.JComponent#getPreferredSize`, `java.awt.LayoutManager#preferredLayoutSize`

public Dimension getPreferredSize(JComponent c)

Returns the specified component's preferred size appropriate for the look and feel. If null is returned, the preferred size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method returns null.

Parameters

c:JComponent: the component whose preferred size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

Returns:Dimension

a Dimension object containing given component's preferred size appropriate for the look and feel

installUI back to summary

installUI	back to summary
public void installUI(JComponent c) Configures the specified component appropriately for the look and feel. This method is invoked when the `ComponentUI` instance is being installed as the UI delegate on the specified component. This method should completely configure the component for the look and feel, including the following: Install default property values for color, fonts, borders, icons, opacity, etc. on the component. Whenever possible, property values initialized by the client program should not be overridden. Install a `LayoutManager` on the component if necessary. Create/add any required sub-components to the component. Create/install event listeners on the component. Create/install a `PropertyChangeListener` on the component in order to detect and respond to component property changes appropriately. Install keyboard UI (mnemonics, traversal, etc.) on the component. Initialize any appropriate instance data. Parameters c:JComponent the component where this UI delegate is being installed See Also `uninstallUI`, `javax.swing.JComponent#setUI`, `javax.swing.JComponent#updateUI`

public void installUI(JComponent c)

Configures the specified component appropriately for the look and feel. This method is invoked when the ComponentUI instance is being installed as the UI delegate on the specified component. This method should completely configure the component for the look and feel, including the following:

Install default property values for color, fonts, borders, icons, opacity, etc. on the component. Whenever possible, property values initialized by the client program should not be overridden.
Install a LayoutManager on the component if necessary.
Create/add any required sub-components to the component.
Create/install event listeners on the component.
Create/install a PropertyChangeListener on the component in order to detect and respond to component property changes appropriately.
Install keyboard UI (mnemonics, traversal, etc.) on the component.
Initialize any appropriate instance data.

Parameters

c:JComponent: the component where this UI delegate is being installed

paint back to summary

paint	back to summary
public void paint(Graphics g, JComponent c) Paints the specified component appropriately for the look and feel. This method is invoked from the `ComponentUI.update` method when the specified component is being painted. Subclasses should override this method and use the specified `Graphics` object to render the content of the component. Parameters g:Graphics the `Graphics` context in which to paint c:JComponent the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components See Also `update`

public void paint(Graphics g, JComponent c)

Paints the specified component appropriately for the look and feel. This method is invoked from the ComponentUI.update method when the specified component is being painted. Subclasses should override this method and use the specified Graphics object to render the content of the component.

Parameters

g:Graphics: the Graphics context in which to paint
c:JComponent: the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

See Also

update

uninstallUI back to summary

uninstallUI	back to summary
public void uninstallUI(JComponent c) Reverses configuration which was done on the specified component during `installUI`. This method is invoked when this `UIComponent` instance is being removed as the UI delegate for the specified component. This method should undo the configuration performed in `installUI`, being careful to leave the `JComponent` instance in a clean state (no extraneous listeners, look-and-feel-specific property objects, etc.). This should include the following: Remove any UI-set borders from the component. Remove any UI-set layout managers on the component. Remove any UI-added sub-components from the component. Remove any UI-added event/property listeners from the component. Remove any UI-installed keyboard UI from the component. Nullify any allocated instance data objects to allow for GC. Parameters c:JComponent the component from which this UI delegate is being removed; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components See Also `installUI`, `javax.swing.JComponent#updateUI`

public void uninstallUI(JComponent c)

Reverses configuration which was done on the specified component during installUI. This method is invoked when this UIComponent instance is being removed as the UI delegate for the specified component. This method should undo the configuration performed in installUI, being careful to leave the JComponent instance in a clean state (no extraneous listeners, look-and-feel-specific property objects, etc.). This should include the following:

Remove any UI-set borders from the component.
Remove any UI-set layout managers on the component.
Remove any UI-added sub-components from the component.
Remove any UI-added event/property listeners from the component.
Remove any UI-installed keyboard UI from the component.
Nullify any allocated instance data objects to allow for GC.

Parameters

c:JComponent: the component from which this UI delegate is being removed; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

update back to summary

update	back to summary
public void update(Graphics g, JComponent c) Notifies this UI delegate that it is time to paint the specified component. This method is invoked by `JComponent` when the specified component is being painted. By default this method fills the specified component with its background color if its `opaque` property is `true`, and then immediately calls `paint`. In general this method need not be overridden by subclasses; all look-and-feel rendering code should reside in the `paint` method. Parameters g:Graphics the `Graphics` context in which to paint c:JComponent the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components See Also `paint`, `javax.swing.JComponent#paintComponent`

public void update(Graphics g, JComponent c)

Notifies this UI delegate that it is time to paint the specified component. This method is invoked by JComponent when the specified component is being painted.

By default this method fills the specified component with its background color if its opaque property is true, and then immediately calls paint. In general this method need not be overridden by subclasses; all look-and-feel rendering code should reside in the paint method.

Parameters

g:Graphics: the Graphics context in which to paint
c:JComponent: the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

public abstract Class ComponentUI

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Constructor Detail

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