ButtonUI
, ColorChooserUI
, ComboBoxUI
, DesktopIconUI
, DesktopPaneUI
, FileChooserUI
, InternalFrameUI
, LabelUI
, LayerUI
, ListUI
, MenuBarUI
, OptionPaneUI
, PanelUI
, PopupMenuUI
, ProgressBarUI
, RootPaneUI
, ScrollBarUI
, ScrollPaneUI
, SeparatorUI
, SliderUI
, SpinnerUI
, SplitPaneUI
, TabbedPaneUI
, TableHeaderUI
, TableUI
, TextUI
, ToolBarUI
, ToolTipUI
, TreeUI
, ViewportUI
public abstract class ComponentUI extends Object
JComponent
class invokes methods from this class in order to delegate operations (painting, layout calculations, etc.) that may vary depending on the look and feel installed. Client programs should not invoke methods on this class directly.
Constructor | Description |
---|---|
ComponentUI() |
Sole constructor. |
Modifier and Type | Method | Description |
---|---|---|
boolean |
contains |
Returns true if the specified x,y location is contained within the look and feel's defined shape of the specified component. |
static ComponentUI |
createUI |
Returns an instance of the UI delegate for the specified component. |
Accessible |
getAccessibleChild |
Returns the i th Accessible child of the object. |
int |
getAccessibleChildrenCount |
Returns the number of accessible children in the object. |
int |
getBaseline |
Returns the baseline. |
Component.BaselineResizeBehavior |
getBaselineResizeBehavior |
Returns an enum indicating how the baseline of the component changes as the size changes. |
Dimension |
getMaximumSize |
Returns the specified component's maximum size appropriate for the look and feel. |
Dimension |
getMinimumSize |
Returns the specified component's minimum size appropriate for the look and feel. |
Dimension |
getPreferredSize |
Returns the specified component's preferred size appropriate for the look and feel. |
void |
installUI |
Configures the specified component appropriately for the look and feel. |
void |
paint |
Paints the specified component appropriately for the look and feel. |
void |
uninstallUI |
Reverses configuration which was done on the specified component during installUI . |
void |
update |
Notifies this UI delegate that it is time to paint the specified component. |
public ComponentUI()
public void installUI(JComponent c)
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: LayoutManager
on the component if necessary. PropertyChangeListener
on the component in order to detect and respond to component property changes appropriately. c
- the component where this UI delegate is being installedpublic void uninstallUI(JComponent c)
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: c
- 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 componentspublic void paint(Graphics g, JComponent c)
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.g
- the Graphics
context in which to paintc
- the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple componentspublic void update(Graphics g, JComponent c)
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.
g
- the Graphics
context in which to paintc
- the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple componentspublic Dimension getPreferredSize(JComponent c)
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
.c
- 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 componentsDimension
object containing given component's preferred size appropriate for the look and feelpublic Dimension getMinimumSize(JComponent c)
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.c
- 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 componentsDimension
object or null
public Dimension getMaximumSize(JComponent c)
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.c
- 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 componentsDimension
object or null
public boolean contains(JComponent c, int x, int y)
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.c
- 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 componentsx
- the x coordinate of the pointy
- the y coordinate of the pointtrue
if the specified x,y
location is contained within the look and feel's defined shape for the given componentpublic static ComponentUI createUI(JComponent c)
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.c
- a JComponent
for which to create a UI delegateComponentUI
object for c
public int getBaseline(JComponent c, int width, int height)
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.
c
- JComponent
baseline is being requested forwidth
- the width to get the baseline forheight
- the height to get the baseline forNullPointerException
- if c
is null
IllegalArgumentException
- if width or height is < 0public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
This method returns BaselineResizeBehavior.OTHER
. Subclasses that support a baseline should override appropriately.
c
- JComponent
to return baseline resize behavior forNullPointerException
- if c
is null
public int getAccessibleChildrenCount(JComponent c)
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.c
- JComponent
for which to get count of accessible childrenpublic Accessible getAccessibleChild(JComponent c, int i)
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.
c
- a JComponent
for which to get a child objecti
- zero-based index of childi
th Accessible
child of the object
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/swing/plaf/ComponentUI.html