Class Container
- All Implemented Interfaces:
ImageObserver
,MenuContainer
,Serializable
- Direct Known Subclasses:
BasicSplitPaneDivider
,CellRendererPane
,DefaultTreeCellEditor.EditorContainer
,JComponent
,Panel
,ScrollPane
,Window
Components added to a container are tracked in a list. The order of the list will define the components' front-to-back stacking order within the container. If no index is specified when adding a component to a container, it will be added to the end of the list (and hence to the bottom of the stacking order).
Note: For details on the focus subsystem, see How to Use the Focus Subsystem, a section in The Java Tutorial, and the Focus Specification for more information.
- Since:
- 1.0
- See Also:
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Nested Class Summary
Modifier and TypeClassDescriptionprotected class
Inner class of Container used to provide default support for accessibility.Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
Fields inherited from class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionAppends the specified component to the end of this container.Adds the specified component to this container at the given position.void
Adds the specified component to the end of this container.void
Adds the specified component to this container with the specified constraints at the specified index.Adds the specified component to this container.void
Adds the specified container listener to receive container events from this container.protected void
Adds the specified component to this container at the specified index.void
Makes this Container displayable by connecting it to a native screen resource.void
Adds a PropertyChangeListener to the listener list.void
addPropertyChangeListener
(String propertyName, PropertyChangeListener listener) Adds a PropertyChangeListener to the listener list for a specific property.void
Sets theComponentOrientation
property of this container and all components contained within it.boolean
areFocusTraversalKeysSet
(int id) Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Container.int
Deprecated.As of JDK version 1.1, replaced by getComponentCount().void
Deprecated.As of JDK version 1.1, replaced bydispatchEvent(AWTEvent e)
void
doLayout()
Causes this container to lay out its components.findComponentAt
(int x, int y) Locates the visible child component that contains the specified position.Locates the visible child component that contains the specified point.float
Returns the alignment along the x axis.float
Returns the alignment along the y axis.getComponent
(int n) Gets the nth component in this container.getComponentAt
(int x, int y) Locates the component that contains the x,y position.Gets the component that contains the specified point.int
Gets the number of components in this panel.Gets all the components in this container.int
getComponentZOrder
(Component comp) Returns the z-order index of the component inside the container.Returns an array of all the container listeners registered on this container.getFocusTraversalKeys
(int id) Returns the Set of focus traversal keys for a given traversal operation for this Container.Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root.Determines the insets of this container, which indicate the size of the container's border.Gets the layout manager for this container.<T extends EventListener>
T[]getListeners
(Class<T> listenerType) Returns an array of all the objects currently registered asFooListener
s upon thisContainer
.Returns the maximum size of this container.Returns the minimum size of this container.getMousePosition
(boolean allowChildren) Returns the position of the mouse pointer in thisContainer
's coordinate space if theContainer
is under the mouse pointer, otherwise returnsnull
.Returns the preferred size of this container.insets()
Deprecated.As of JDK version 1.1, replaced bygetInsets()
.void
Invalidates the container.boolean
Checks if the component is contained in the component hierarchy of this container.boolean
Returns whether this Container is the root of a focus traversal cycle.boolean
isFocusCycleRoot
(Container container) Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle.final boolean
Returns whether this container provides focus traversal policy.boolean
Returns whether the focus traversal policy has been explicitly set for this Container.boolean
Indicates if this container is a validate root.void
layout()
Deprecated.As of JDK version 1.1, replaced bydoLayout()
.void
list
(PrintStream out, int indent) Prints a listing of this container to the specified output stream.void
list
(PrintWriter out, int indent) Prints out a list, starting at the specified indentation, to the specified print writer.locate
(int x, int y) Deprecated.As of JDK version 1.1, replaced bygetComponentAt(int, int)
.Deprecated.As of JDK version 1.1, replaced bygetMinimumSize()
.void
Paints the container.void
Paints each of the components in this container.protected String
Returns a string representing the state of thisContainer
.Deprecated.As of JDK version 1.1, replaced bygetPreferredSize()
.void
Prints the container.void
Prints each of the components in this container.protected void
Processes container events occurring on this container by dispatching them to any registered ContainerListener objects.protected void
Processes events on this container.void
remove
(int index) Removes the component, specified byindex
, from this container.void
Removes the specified component from this container.void
Removes all the components from this container.void
Removes the specified container listener so it no longer receives container events from this container.void
Makes this Container undisplayable by removing its connection to its native screen resource.void
setComponentZOrder
(Component comp, int index) Moves the specified component to the specified z-order index in the container.void
setFocusCycleRoot
(boolean focusCycleRoot) Sets whether this Container is the root of a focus traversal cycle.void
setFocusTraversalKeys
(int id, Set<? extends AWTKeyStroke> keystrokes) Sets the focus traversal keys for a given traversal operation for this Container.void
Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root.final void
setFocusTraversalPolicyProvider
(boolean provider) Sets whether this container will be used to provide focus traversal policy.void
Sets the font of this container.void
setLayout
(LayoutManager mgr) Sets the layout manager for this container.void
Transfers the focus down one focus traversal cycle.void
Updates the container.void
validate()
Validates this container and all of its subcomponents.protected void
Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid).Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAccessibleContext, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setMixingCutoutShape, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
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Constructor Details
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Container
public Container()Constructs a new Container. Containers can be extended directly, but are lightweight in this case and must be contained by a parent somewhere higher up in the component tree that is native. (such as Frame for example).
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Method Details
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getComponentCount
public int getComponentCount()Gets the number of components in this panel.Note: This method should be called under AWT tree lock.
- Returns:
- the number of components in this panel.
- Since:
- 1.1
- See Also:
-
countComponents
Deprecated.As of JDK version 1.1, replaced by getComponentCount().Returns the number of components in this container.- Returns:
- the number of components in this container
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getComponent
Gets the nth component in this container.Note: This method should be called under AWT tree lock.
- Parameters:
n
- the index of the component to get.- Returns:
- the nth component in this container.
- Throws:
ArrayIndexOutOfBoundsException
- if the nth value does not exist.- See Also:
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getComponents
Gets all the components in this container.Note: This method should be called under AWT tree lock.
- Returns:
- an array of all the components in this container.
- See Also:
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getInsets
Determines the insets of this container, which indicate the size of the container's border.A
Frame
object, for example, has a top inset that corresponds to the height of the frame's title bar.- Returns:
- the insets of this container.
- Since:
- 1.1
- See Also:
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insets
Deprecated.As of JDK version 1.1, replaced bygetInsets()
.Returns the insets for this container.- Returns:
- the insets for this container
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add
Appends the specified component to the end of this container. This is a convenience method foraddImpl(java.awt.Component, java.lang.Object, int)
.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
comp
- the component to be added- Returns:
- the component argument
- Throws:
NullPointerException
- ifcomp
isnull
- See Also:
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add
Adds the specified component to this container. This is a convenience method foraddImpl(java.awt.Component, java.lang.Object, int)
.This method is obsolete as of 1.1. Please use the method
add(Component, Object)
instead.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
name
- the name of the component to be addedcomp
- the component to be added- Returns:
- the component added
- Throws:
NullPointerException
- ifcomp
isnull
- See Also:
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add
Adds the specified component to this container at the given position. This is a convenience method foraddImpl(java.awt.Component, java.lang.Object, int)
.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
comp
- the component to be addedindex
- the position at which to insert the component, or-1
to append the component to the end- Returns:
- the component
comp
- Throws:
NullPointerException
- ifcomp
isnull
IllegalArgumentException
- ifindex
is invalid (seeaddImpl(java.awt.Component, java.lang.Object, int)
for details)- See Also:
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setComponentZOrder
Moves the specified component to the specified z-order index in the container. The z-order determines the order that components are painted; the component with the highest z-order paints first and the component with the lowest z-order paints last. Where components overlap, the component with the lower z-order paints over the component with the higher z-order.If the component is a child of some other container, it is removed from that container before being added to this container. The important difference between this method and
java.awt.Container.add(Component, int)
is that this method doesn't callremoveNotify
on the component while removing it from its previous container unless necessary and when allowed by the underlying native windowing system. This way, if the component has the keyboard focus, it maintains the focus when moved to the new position.This property is guaranteed to apply only to lightweight non-
Container
components.This method changes layout-related information, and therefore, invalidates the component hierarchy.
Note: Not all platforms support changing the z-order of heavyweight components from one container into another without the call to
removeNotify
. There is no way to detect whether a platform supports this, so developers shouldn't make any assumptions.- Parameters:
comp
- the component to be movedindex
- the position in the container's list to insert the component, wheregetComponentCount()
appends to the end- Throws:
NullPointerException
- ifcomp
isnull
IllegalArgumentException
- ifcomp
is one of the container's parentsIllegalArgumentException
- ifindex
is not in the range[0, getComponentCount()]
for moving between containers, or not in the range[0, getComponentCount()-1]
for moving inside a containerIllegalArgumentException
- if adding a container to itselfIllegalArgumentException
- if adding aWindow
to a container- Since:
- 1.5
- See Also:
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getComponentZOrder
Returns the z-order index of the component inside the container. The higher a component is in the z-order hierarchy, the lower its index. The component with the lowest z-order index is painted last, above all other child components.- Parameters:
comp
- the component being queried- Returns:
- the z-order index of the component; otherwise
returns -1 if the component is
null
or doesn't belong to the container - Since:
- 1.5
- See Also:
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add
Adds the specified component to the end of this container. Also notifies the layout manager to add the component to this container's layout using the specified constraints object. This is a convenience method foraddImpl(java.awt.Component, java.lang.Object, int)
.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
comp
- the component to be addedconstraints
- an object expressing layout constraints for this component- Throws:
NullPointerException
- ifcomp
isnull
- Since:
- 1.1
- See Also:
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add
Adds the specified component to this container with the specified constraints at the specified index. Also notifies the layout manager to add the component to the this container's layout using the specified constraints object. This is a convenience method foraddImpl(java.awt.Component, java.lang.Object, int)
.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
comp
- the component to be addedconstraints
- an object expressing layout constraints for thisindex
- the position in the container's list at which to insert the component;-1
means insert at the end component- Throws:
NullPointerException
- ifcomp
isnull
IllegalArgumentException
- ifindex
is invalid (seeaddImpl(java.awt.Component, java.lang.Object, int)
for details)- See Also:
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addImpl
Adds the specified component to this container at the specified index. This method also notifies the layout manager to add the component to this container's layout using the specified constraints object via theaddLayoutComponent
method.The constraints are defined by the particular layout manager being used. For example, the
BorderLayout
class defines five constraints:BorderLayout.NORTH
,BorderLayout.SOUTH
,BorderLayout.EAST
,BorderLayout.WEST
, andBorderLayout.CENTER
.The
GridBagLayout
class requires aGridBagConstraints
object. Failure to pass the correct type of constraints object results in anIllegalArgumentException
.If the current layout manager implements
LayoutManager2
, thenLayoutManager2.addLayoutComponent(Component,Object)
is invoked on it. If the current layout manager does not implementLayoutManager2
, and constraints is aString
, thenLayoutManager.addLayoutComponent(String,Component)
is invoked on it.If the component is not an ancestor of this container and has a non-null parent, it is removed from its current parent before it is added to this container.
This is the method to override if a program needs to track every add request to a container as all other add methods defer to this one. An overriding method should usually include a call to the superclass's version of the method:
super.addImpl(comp, constraints, index)
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
- Parameters:
comp
- the component to be addedconstraints
- an object expressing layout constraints for this componentindex
- the position in the container's list at which to insert the component, where-1
means append to the end- Throws:
IllegalArgumentException
- ifindex
is invalid; ifcomp
is a child of this container, the valid range is[-1, getComponentCount()-1]
; if component is not a child of this container, the valid range is[-1, getComponentCount()]
IllegalArgumentException
- ifcomp
is an ancestor of this containerIllegalArgumentException
- if adding a window to a containerNullPointerException
- ifcomp
isnull
- Since:
- 1.1
- See Also:
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remove
public void remove(int index) Removes the component, specified byindex
, from this container. This method also notifies the layout manager to remove the component from this container's layout via theremoveLayoutComponent
method.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
- Parameters:
index
- the index of the component to be removed- Throws:
ArrayIndexOutOfBoundsException
- ifindex
is not in range[0, getComponentCount()-1]
- Since:
- 1.1
- See Also:
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remove
Removes the specified component from this container. This method also notifies the layout manager to remove the component from this container's layout via theremoveLayoutComponent
method.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
- Parameters:
comp
- the component to be removed- Throws:
NullPointerException
- ifcomp
isnull
- See Also:
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removeAll
public void removeAll()Removes all the components from this container. This method also notifies the layout manager to remove the components from this container's layout via theremoveLayoutComponent
method.This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
- See Also:
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getLayout
Gets the layout manager for this container.- Returns:
- the current layout manager for this container
- See Also:
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setLayout
Sets the layout manager for this container.This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Parameters:
mgr
- the specified layout manager- See Also:
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doLayout
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layout
Deprecated.As of JDK version 1.1, replaced bydoLayout()
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isValidateRoot
public boolean isValidateRoot()Indicates if this container is a validate root.Layout-related changes, such as bounds of the validate root descendants, do not affect the layout of the validate root parent. This peculiarity enables the
invalidate()
method to stop invalidating the component hierarchy when the method encounters a validate root. However, to preserve backward compatibility this new optimized behavior is enabled only when thejava.awt.smartInvalidate
system property value is set totrue
.If a component hierarchy contains validate roots and the new optimized
invalidate()
behavior is enabled, thevalidate()
method must be invoked on the validate root of a previously invalidated component to restore the validity of the hierarchy later. Otherwise, calling thevalidate()
method on the top-level container (such as aFrame
object) should be used to restore the validity of the component hierarchy.The
Window
class and theApplet
class are the validate roots in AWT. Swing introduces more validate roots.- Returns:
- whether this container is a validate root
- Since:
- 1.7
- See Also:
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invalidate
public void invalidate()Invalidates the container.If the
LayoutManager
installed on this container is an instance of theLayoutManager2
interface, then theLayoutManager2.invalidateLayout(Container)
method is invoked on it supplying thisContainer
as the argument.Afterwards this method marks this container invalid, and invalidates its ancestors. See the
Component.invalidate()
method for more details.- Overrides:
invalidate
in classComponent
- See Also:
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validate
public void validate()Validates this container and all of its subcomponents.Validating a container means laying out its subcomponents. Layout-related changes, such as setting the bounds of a component, or adding a component to the container, invalidate the container automatically. Note that the ancestors of the container may be invalidated also (see
Component.invalidate()
for details.) Therefore, to restore the validity of the hierarchy, thevalidate()
method should be invoked on the top-most invalid container of the hierarchy.Validating the container may be a quite time-consuming operation. For performance reasons a developer may postpone the validation of the hierarchy till a set of layout-related operations completes, e.g. after adding all the children to the container.
If this
Container
is not valid, this method invokes thevalidateTree
method and marks thisContainer
as valid. Otherwise, no action is performed. -
validateTree
protected void validateTree()Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid). Synchronization should be provided by the method that calls this one:validate
.- See Also:
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setFont
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getPreferredSize
Returns the preferred size of this container. If the preferred size has not been set explicitly byComponent.setPreferredSize(Dimension)
and thisContainer
has anon-null
LayoutManager
, thenLayoutManager.preferredLayoutSize(Container)
is used to calculate the preferred size.Note: some implementations may cache the value returned from the
LayoutManager
. Implementations that cache need not invokepreferredLayoutSize
on theLayoutManager
every time this method is invoked, rather theLayoutManager
will only be queried after theContainer
becomes invalid.- Overrides:
getPreferredSize
in classComponent
- Returns:
- an instance of
Dimension
that represents the preferred size of this container. - See Also:
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preferredSize
Deprecated.As of JDK version 1.1, replaced bygetPreferredSize()
.Description copied from class:Component
Returns the component's preferred size.- Overrides:
preferredSize
in classComponent
- Returns:
- the component's preferred size
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getMinimumSize
Returns the minimum size of this container. If the minimum size has not been set explicitly byComponent.setMinimumSize(Dimension)
and thisContainer
has anon-null
LayoutManager
, thenLayoutManager.minimumLayoutSize(Container)
is used to calculate the minimum size.Note: some implementations may cache the value returned from the
LayoutManager
. Implementations that cache need not invokeminimumLayoutSize
on theLayoutManager
every time this method is invoked, rather theLayoutManager
will only be queried after theContainer
becomes invalid.- Overrides:
getMinimumSize
in classComponent
- Returns:
- an instance of
Dimension
that represents the minimum size of this container. - Since:
- 1.1
- See Also:
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minimumSize
Deprecated.As of JDK version 1.1, replaced bygetMinimumSize()
.Description copied from class:Component
Returns the minimum size of this component.- Overrides:
minimumSize
in classComponent
- Returns:
- the minimum size of this component
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getMaximumSize
Returns the maximum size of this container. If the maximum size has not been set explicitly byComponent.setMaximumSize(Dimension)
and theLayoutManager
installed on thisContainer
is an instance ofLayoutManager2
, thenLayoutManager2.maximumLayoutSize(Container)
is used to calculate the maximum size.Note: some implementations may cache the value returned from the
LayoutManager2
. Implementations that cache need not invokemaximumLayoutSize
on theLayoutManager2
every time this method is invoked, rather theLayoutManager2
will only be queried after theContainer
becomes invalid.- Overrides:
getMaximumSize
in classComponent
- Returns:
- an instance of
Dimension
that represents the maximum size of this container. - See Also:
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getAlignmentX
public float getAlignmentX()Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.- Overrides:
getAlignmentX
in classComponent
- Returns:
- the horizontal alignment of this component
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getAlignmentY
public float getAlignmentY()Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.- Overrides:
getAlignmentY
in classComponent
- Returns:
- the vertical alignment of this component
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paint
Paints the container. This forwards the paint to any lightweight components that are children of this container. If this method is reimplemented, super.paint(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, paint() will not be forwarded to that child. -
update
Updates the container. This forwards the update to any lightweight components that are children of this container. If this method is reimplemented, super.update(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, update() will not be forwarded to that child. -
print
Prints the container. This forwards the print to any lightweight components that are children of this container. If this method is reimplemented, super.print(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, print() will not be forwarded to that child. -
paintComponents
Paints each of the components in this container.- Parameters:
g
- the graphics context.- See Also:
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printComponents
Prints each of the components in this container.- Parameters:
g
- the graphics context.- See Also:
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addContainerListener
Adds the specified container listener to receive container events from this container. If l is null, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
l
- the container listener- See Also:
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removeContainerListener
Removes the specified container listener so it no longer receives container events from this container. If l is null, no exception is thrown and no action is performed.Refer to AWT Threading Issues for details on AWT's threading model.
- Parameters:
l
- the container listener- See Also:
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getContainerListeners
Returns an array of all the container listeners registered on this container.- Returns:
- all of this container's
ContainerListener
s or an empty array if no container listeners are currently registered - Since:
- 1.4
- See Also:
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getListeners
Returns an array of all the objects currently registered asFooListener
s upon thisContainer
.FooListener
s are registered using theaddFooListener
method.You can specify the
listenerType
argument with a class literal, such asFooListener.class
. For example, you can query aContainer c
for its container listeners with the following code:ContainerListener[] cls = (ContainerListener[])(c.getListeners(ContainerListener.class));
If no such listeners exist, this method returns an empty array.- Overrides:
getListeners
in classComponent
- Type Parameters:
T
- the type of the listeners- Parameters:
listenerType
- the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
- Returns:
- an array of all objects registered as
FooListener
s on this container, or an empty array if no such listeners have been added - Throws:
ClassCastException
- iflistenerType
doesn't specify a class or interface that implementsjava.util.EventListener
NullPointerException
- iflistenerType
isnull
- Since:
- 1.3
- See Also:
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processEvent
Processes events on this container. If the event is aContainerEvent
, it invokes theprocessContainerEvent
method, else it invokes its superclass'sprocessEvent
.Note that if the event parameter is
null
the behavior is unspecified and may result in an exception.- Overrides:
processEvent
in classComponent
- Parameters:
e
- the event- See Also:
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processContainerEvent
Processes container events occurring on this container by dispatching them to any registered ContainerListener objects. NOTE: This method will not be called unless container events are enabled for this component; this happens when one of the following occurs:- A ContainerListener object is registered via
addContainerListener
- Container events are enabled via
enableEvents
Note that if the event parameter is
null
the behavior is unspecified and may result in an exception.- Parameters:
e
- the container event- See Also:
- A ContainerListener object is registered via
-
deliverEvent
Deprecated.As of JDK version 1.1, replaced bydispatchEvent(AWTEvent e)
- Overrides:
deliverEvent
in classComponent
- Parameters:
e
- the event to deliver
-
getComponentAt
Locates the component that contains the x,y position. The top-most child component is returned in the case where there is overlap in the components. This is determined by finding the component closest to the index 0 that claims to contain the given point via Component.contains(), except that Components which have native peers take precedence over those which do not (i.e., lightweight Components).- Overrides:
getComponentAt
in classComponent
- Parameters:
x
- the x coordinatey
- the y coordinate- Returns:
- null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned; otherwise the top-most child is returned.
- Since:
- 1.1
- See Also:
-
locate
Deprecated.As of JDK version 1.1, replaced bygetComponentAt(int, int)
.Description copied from class:Component
Returns the component occupying the position specified (this component, or immediate child component, or null if neither of the first two occupies the location). -
getComponentAt
Gets the component that contains the specified point.- Overrides:
getComponentAt
in classComponent
- Parameters:
p
- the point.- Returns:
- returns the component that contains the point,
or
null
if the component does not contain the point. - Since:
- 1.1
- See Also:
-
getMousePosition
Returns the position of the mouse pointer in thisContainer
's coordinate space if theContainer
is under the mouse pointer, otherwise returnsnull
. This method is similar toComponent.getMousePosition()
with the exception that it can take theContainer
's children into account. IfallowChildren
isfalse
, this method will return a non-null value only if the mouse pointer is above theContainer
directly, not above the part obscured by children. IfallowChildren
istrue
, this method returns a non-null value if the mouse pointer is aboveContainer
or any of its descendants.- Parameters:
allowChildren
- true if children should be taken into account- Returns:
- mouse coordinates relative to this
Component
, or null - Throws:
HeadlessException
- if GraphicsEnvironment.isHeadless() returns true- Since:
- 1.5
- See Also:
-
findComponentAt
Locates the visible child component that contains the specified position. The top-most child component is returned in the case where there is overlap in the components. If the containing child component is a Container, this method will continue searching for the deepest nested child component. Components which are not visible are ignored during the search.The findComponentAt method is different from getComponentAt in that getComponentAt only searches the Container's immediate children; if the containing component is a Container, findComponentAt will search that child to find a nested component.
- Parameters:
x
- the x coordinatey
- the y coordinate- Returns:
- null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned.
- Since:
- 1.2
- See Also:
-
findComponentAt
Locates the visible child component that contains the specified point. The top-most child component is returned in the case where there is overlap in the components. If the containing child component is a Container, this method will continue searching for the deepest nested child component. Components which are not visible are ignored during the search.The findComponentAt method is different from getComponentAt in that getComponentAt only searches the Container's immediate children; if the containing component is a Container, findComponentAt will search that child to find a nested component.
- Parameters:
p
- the point.- Returns:
- null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned.
- Throws:
NullPointerException
- ifp
isnull
- Since:
- 1.2
- See Also:
-
addNotify
public void addNotify()Makes this Container displayable by connecting it to a native screen resource. Making a container displayable will cause all of its children to be made displayable. This method is called internally by the toolkit and should not be called directly by programs. -
removeNotify
public void removeNotify()Makes this Container undisplayable by removing its connection to its native screen resource. Making a container undisplayable will cause all of its children to be made undisplayable. This method is called by the toolkit internally and should not be called directly by programs.- Overrides:
removeNotify
in classComponent
- See Also:
-
isAncestorOf
Checks if the component is contained in the component hierarchy of this container.- Parameters:
c
- the component- Returns:
true
if it is an ancestor;false
otherwise.- Since:
- 1.1
-
paramString
Returns a string representing the state of thisContainer
. 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 benull
.- Overrides:
paramString
in classComponent
- Returns:
- the parameter string of this container
-
list
Prints a listing of this container to the specified output stream. The listing starts at the specified indentation.The immediate children of the container are printed with an indentation of
indent+1
. The children of those children are printed atindent+2
and so on.- Overrides:
list
in classComponent
- Parameters:
out
- a print streamindent
- the number of spaces to indent- Throws:
NullPointerException
- ifout
isnull
- Since:
- 1.0
- See Also:
-
list
Prints out a list, starting at the specified indentation, to the specified print writer.The immediate children of the container are printed with an indentation of
indent+1
. The children of those children are printed atindent+2
and so on.- Overrides:
list
in classComponent
- Parameters:
out
- a print writerindent
- the number of spaces to indent- Throws:
NullPointerException
- ifout
isnull
- Since:
- 1.1
- See Also:
-
setFocusTraversalKeys
Sets the focus traversal keys for a given traversal operation for this Container.The default values for a Container's focus traversal keys are implementation-dependent. Sun recommends that all implementations for a particular native platform use the same default values. The recommendations for Windows and Unix are listed below. These recommendations are used in the Sun AWT implementations.
Recommended default values for a Container's focus traversal keys Identifier Meaning Default KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS Normal forward keyboard traversal TAB on KEY_PRESSED, CTRL-TAB on KEY_PRESSED KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS Normal reverse keyboard traversal SHIFT-TAB on KEY_PRESSED, CTRL-SHIFT-TAB on KEY_PRESSED KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS Go up one focus traversal cycle none KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS Go down one focus traversal cycle none Using the AWTKeyStroke API, client code can specify on which of two specific KeyEvents, KEY_PRESSED or KEY_RELEASED, the focus traversal operation will occur. Regardless of which KeyEvent is specified, however, all KeyEvents related to the focus traversal key, including the associated KEY_TYPED event, will be consumed, and will not be dispatched to any Container. It is a runtime error to specify a KEY_TYPED event as mapping to a focus traversal operation, or to map the same event to multiple default focus traversal operations.
If a value of null is specified for the Set, this Container inherits the Set from its parent. If all ancestors of this Container have null specified for the Set, then the current KeyboardFocusManager's default Set is used.
This method may throw a
ClassCastException
if anyObject
inkeystrokes
is not anAWTKeyStroke
.- Overrides:
setFocusTraversalKeys
in classComponent
- Parameters:
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYSkeystrokes
- the Set of AWTKeyStroke for the specified operation- Throws:
IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS, or if keystrokes contains null, or if any keystroke represents a KEY_TYPED event, or if any keystroke already maps to another focus traversal operation for this Container- Since:
- 1.4
- See Also:
-
getFocusTraversalKeys
Returns the Set of focus traversal keys for a given traversal operation for this Container. (SeesetFocusTraversalKeys
for a full description of each key.)If a Set of traversal keys has not been explicitly defined for this Container, then this Container's parent's Set is returned. If no Set has been explicitly defined for any of this Container's ancestors, then the current KeyboardFocusManager's default Set is returned.
- Overrides:
getFocusTraversalKeys
in classComponent
- Parameters:
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS- Returns:
- the Set of AWTKeyStrokes for the specified operation. The Set will be unmodifiable, and may be empty. null will never be returned.
- Throws:
IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS- Since:
- 1.4
- See Also:
-
areFocusTraversalKeysSet
public boolean areFocusTraversalKeysSet(int id) Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Container. If this method returnsfalse
, this Container is inheriting the Set from an ancestor, or from the current KeyboardFocusManager.- Overrides:
areFocusTraversalKeysSet
in classComponent
- Parameters:
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS- Returns:
true
if the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component;false
otherwise.- Throws:
IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS- Since:
- 1.4
-
isFocusCycleRoot
Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle. Each focus traversal cycle has only a single focus cycle root and each Container which is not a focus cycle root belongs to only a single focus traversal cycle. Containers which are focus cycle roots belong to two cycles: one rooted at the Container itself, and one rooted at the Container's nearest focus-cycle-root ancestor. This method will returntrue
for both such Containers in this case.- Overrides:
isFocusCycleRoot
in classComponent
- Parameters:
container
- the Container to be tested- Returns:
true
if the specified Container is a focus-cycle- root of this Container;false
otherwise- Since:
- 1.4
- See Also:
-
setFocusTraversalPolicy
Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root. If the argument is null, this Container inherits its policy from its focus- cycle-root ancestor. If the argument is non-null, this policy will be inherited by all focus-cycle-root children that have no keyboard- traversal policy of their own (as will, recursively, their focus-cycle- root children).If this Container is not a focus cycle root, the policy will be remembered, but will not be used or inherited by this or any other Containers until this Container is made a focus cycle root.
- Parameters:
policy
- the new focus traversal policy for this Container- Since:
- 1.4
- See Also:
-
getFocusTraversalPolicy
Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root. If no traversal policy has been explicitly set for this Container, then this Container's focus-cycle-root ancestor's policy is returned.- Returns:
- this Container's focus traversal policy, or null if this Container is not a focus cycle root.
- Since:
- 1.4
- See Also:
-
isFocusTraversalPolicySet
public boolean isFocusTraversalPolicySet()Returns whether the focus traversal policy has been explicitly set for this Container. If this method returnsfalse
, this Container will inherit its focus traversal policy from an ancestor.- Returns:
true
if the focus traversal policy has been explicitly set for this Container;false
otherwise.- Since:
- 1.4
-
setFocusCycleRoot
public void setFocusCycleRoot(boolean focusCycleRoot) Sets whether this Container is the root of a focus traversal cycle. Once focus enters a traversal cycle, typically it cannot leave it via focus traversal unless one of the up- or down-cycle keys is pressed. Normal traversal is limited to this Container, and all of this Container's descendants that are not descendants of inferior focus cycle roots. Note that a FocusTraversalPolicy may bend these restrictions, however. For example, ContainerOrderFocusTraversalPolicy supports implicit down-cycle traversal.The alternative way to specify the traversal order of this Container's children is to make this Container a focus traversal policy provider.
- Parameters:
focusCycleRoot
- indicates whether this Container is the root of a focus traversal cycle- Since:
- 1.4
- See Also:
-
isFocusCycleRoot
public boolean isFocusCycleRoot()Returns whether this Container is the root of a focus traversal cycle. Once focus enters a traversal cycle, typically it cannot leave it via focus traversal unless one of the up- or down-cycle keys is pressed. Normal traversal is limited to this Container, and all of this Container's descendants that are not descendants of inferior focus cycle roots. Note that a FocusTraversalPolicy may bend these restrictions, however. For example, ContainerOrderFocusTraversalPolicy supports implicit down-cycle traversal.- Returns:
- whether this Container is the root of a focus traversal cycle
- Since:
- 1.4
- See Also:
-
setFocusTraversalPolicyProvider
public final void setFocusTraversalPolicyProvider(boolean provider) Sets whether this container will be used to provide focus traversal policy. Container with this property astrue
will be used to acquire focus traversal policy instead of closest focus cycle root ancestor.- Parameters:
provider
- indicates whether this container will be used to provide focus traversal policy- Since:
- 1.5
- See Also:
-
isFocusTraversalPolicyProvider
public final boolean isFocusTraversalPolicyProvider()Returns whether this container provides focus traversal policy. If this property is set totrue
then when keyboard focus manager searches container hierarchy for focus traversal policy and encounters this container before any other container with this property as true or focus cycle roots then its focus traversal policy will be used instead of focus cycle root's policy.- Returns:
true
if this container provides focus traversal policy,false
otherwise- Since:
- 1.5
- See Also:
-
transferFocusDownCycle
public void transferFocusDownCycle()Transfers the focus down one focus traversal cycle. If this Container is a focus cycle root, then the focus owner is set to this Container's default Component to focus, and the current focus cycle root is set to this Container. If this Container is not a focus cycle root, then no focus traversal operation occurs.- Since:
- 1.4
- See Also:
-
applyComponentOrientation
Sets theComponentOrientation
property of this container and all components contained within it.This method changes layout-related information, and therefore, invalidates the component hierarchy.
- Overrides:
applyComponentOrientation
in classComponent
- Parameters:
o
- the new component orientation of this container and the components contained within it.- Throws:
NullPointerException
- iforientation
is null.- Since:
- 1.4
- See Also:
-
addPropertyChangeListener
Adds a PropertyChangeListener to the listener list. The listener is registered for all bound properties of this class, including the following:- this Container's font ("font")
- this Container's background color ("background")
- this Container's foreground color ("foreground")
- this Container's focusability ("focusable")
- this Container's focus traversal keys enabled state ("focusTraversalKeysEnabled")
- this Container's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
- this Container's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
- this Container's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
- this Container's Set of DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleFocusTraversalKeys")
- this Container's focus traversal policy ("focusTraversalPolicy")
- this Container's focus-cycle-root state ("focusCycleRoot")
If listener is null, no exception is thrown and no action is performed.
- Overrides:
addPropertyChangeListener
in classComponent
- Parameters:
listener
- the PropertyChangeListener to be added- See Also:
-
addPropertyChangeListener
Adds a PropertyChangeListener to the listener list for a specific property. The specified property may be user-defined, or one of the following defaults:- this Container's font ("font")
- this Container's background color ("background")
- this Container's foreground color ("foreground")
- this Container's focusability ("focusable")
- this Container's focus traversal keys enabled state ("focusTraversalKeysEnabled")
- this Container's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
- this Container's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
- this Container's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
- this Container's Set of DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleFocusTraversalKeys")
- this Container's focus traversal policy ("focusTraversalPolicy")
- this Container's focus-cycle-root state ("focusCycleRoot")
- this Container's focus-traversal-policy-provider state("focusTraversalPolicyProvider")
- this Container's focus-traversal-policy-provider state("focusTraversalPolicyProvider")
If listener is null, no exception is thrown and no action is performed.
- Overrides:
addPropertyChangeListener
in classComponent
- Parameters:
propertyName
- one of the property names listed abovelistener
- the PropertyChangeListener to be added- See Also:
-