java.lang.Object | |
↳ | javax.swing.plaf.ComponentUI |
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The base class for all UI delegate objects in the Swing pluggable
look and feel architecture. The UI delegate object for a Swing
component is responsible for implementing the aspects of the
component that depend on the look and feel.
The 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.
Public Constructors | |||||||||||
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Sole constructor.
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Public Methods | |||||||||||
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Returns
true if the specified x,y location is
contained within the look and feel's defined shape of the specified
component. | |||||||||||
Returns an instance of the UI delegate for the specified component.
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Returns the
i th Accessible child of the object. | |||||||||||
Returns the number of accessible children in the object.
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Returns the baseline.
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Returns an enum indicating how the baseline of he component
changes as the size changes.
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Returns the specified component's maximum size appropriate for
the look and feel.
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Returns the specified component's minimum size appropriate for
the look and feel.
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Returns the specified component's preferred size appropriate for
the look and feel.
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Configures the specified component appropriate for the look and feel.
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Paints the specified component appropriate for the look and feel.
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Reverses configuration which was done on the specified component during
installUI . | |||||||||||
Notifies this UI delegate that it's time to paint the specified
component.
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Inherited Methods | |||||||||||
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Sole constructor. (For invocation by subclass constructors, typically implicit.)
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.
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 components |
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x | the x coordinate of the point |
y | the y coordinate of the point |
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.
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.
i | zero-based index of child |
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i
th Accessible
child of the object
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.
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.
c | JComponent baseline is being requested for |
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width | the width to get the baseline for |
height | the height to get the baseline for |
NullPointerException | if c is null |
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IllegalArgumentException | if width or height is < 0 |
Returns an enum indicating how the baseline of he 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.
c | JComponent to return baseline resize behavior for |
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NullPointerException | if c is null |
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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.
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 components |
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Dimension
object or null
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.
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 components |
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Dimension
object or null
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
.
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 components |
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Configures the specified component appropriate 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:
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 installed |
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Paints the specified component appropriate 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.
g | the Graphics context in which to paint |
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c | the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components |
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:
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 components |
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Notifies this UI delegate that it's time to paint the specified
component. This method is invoked by JComponent
when the specified component is being painted.
By default this method will fill the specified component with
its background color (if its opaque
property is
true
) and then immediately call 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 paint |
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c | the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components |