public abstract classComponentextendsObjectimplementsImageObserver,MenuContainer,Serializable
TheComponent
class is the abstract superclass of the nonmenu-related Abstract Window Toolkit components. ClassComponent
can also be extended directly to create a lightweight component. A lightweight component is a component that is not associated with a native window. On the contrary, a heavyweight component is associated with a native window. TheisLightweight()
method may be used to distinguish between the two kinds of the components.
Lightweight and heavyweight components may be mixed in a single component hierarchy. However, for correct operating of such a mixed hierarchy of components, the whole hierarchy must be valid. When the hierarchy gets invalidated, like after changing the bounds of components, or adding/removing components to/from containers, the whole hierarchy must be validated afterwards by means of theContainer.validate()
method invoked on the top-most invalid container of the hierarchy.
Serializable
protocol will be saved when the object is stored. If an AWT object has listeners that aren't marked serializable, they will be dropped atwriteObject
time. Developers will need, as always, to consider the implications of making an object serializable. One situation to watch out for is this:import java.awt.*; import java.awt.event.*; import java.io.Serializable; class MyApp implements ActionListener, Serializable { BigObjectThatShouldNotBeSerializedWithAButton bigOne; Button aButton = new Button(); MyApp() { // Oops, now aButton has a listener with a reference // to bigOne! aButton.addActionListener(this); } public void actionPerformed(ActionEvent e) { System.out.println("Hello There"); } }In this example, serializing
aButton
by itself will causeMyApp
and everything it refers to to be serialized as well. The problem is that the listener is serializable by coincidence, not by design. To separate the decisions aboutMyApp
and theActionListener
being serializable one can use a nested class, as in the following example:import java.awt.*; import java.awt.event.*; import java.io.Serializable; class MyApp implements java.io.Serializable { BigObjectThatShouldNotBeSerializedWithAButton bigOne; Button aButton = new Button(); static class MyActionListener implements ActionListener { public void actionPerformed(ActionEvent e) { System.out.println("Hello There"); } } MyApp() { aButton.addActionListener(new MyActionListener()); } }
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
For details on the focus subsystem, see How to Use the Focus Subsystem, a section inThe Java Tutorial, and theFocus Specification for more information.
Modifier and Type | Class | Description |
---|---|---|
protected class | Component.AccessibleAWTComponent | Inner class of Component used to provide default support for accessibility. |
static class | Component.BaselineResizeBehavior | Enumeration of the common ways the baseline of a component can change as the size changes. |
protected class | Component.BltBufferStrategy | Inner class for blitting offscreen surfaces to a component. |
protected class | Component.FlipBufferStrategy | Inner class for flipping buffers on a component. |
Modifier and Type | Field | Description |
---|---|---|
protectedAccessibleContext | accessibleContext | The AccessibleContext associated with thisComponent . |
static float | BOTTOM_ALIGNMENT | Ease-of-use constant for getAlignmentY . |
static float | CENTER_ALIGNMENT | Ease-of-use constant for getAlignmentY andgetAlignmentX . |
static float | LEFT_ALIGNMENT | Ease-of-use constant for getAlignmentX . |
static float | RIGHT_ALIGNMENT | Ease-of-use constant for getAlignmentX . |
static float | TOP_ALIGNMENT | Ease-of-use constant for getAlignmentY() . |
ABORT,ALLBITS,ERROR,FRAMEBITS,HEIGHT,PROPERTIES,SOMEBITS,WIDTH
Modifier | Constructor | Description |
---|---|---|
protected | Component() | Constructs a new component. |
Modifier and Type | Method | Description |
---|---|---|
boolean | action(Event evt,Object what) | Deprecated. As of JDK version 1.1, should register this component as ActionListener on component which fires action events. |
void | add(PopupMenu popup) | Adds the specified popup menu to the component. |
void | addComponentListener(ComponentListener l) | Adds the specified component listener to receive component events from this component. |
void | addFocusListener(FocusListener l) | Adds the specified focus listener to receive focus events from this component when this component gains input focus. |
void | addHierarchyBoundsListener(HierarchyBoundsListener l) | Adds the specified hierarchy bounds listener to receive hierarchy bounds events from this component when the hierarchy to which this container belongs changes. |
void | addHierarchyListener(HierarchyListener l) | Adds the specified hierarchy listener to receive hierarchy changed events from this component when the hierarchy to which this container belongs changes. |
void | addInputMethodListener(InputMethodListener l) | Adds the specified input method listener to receive input method events from this component. |
void | addKeyListener(KeyListener l) | Adds the specified key listener to receive key events from this component. |
void | addMouseListener(MouseListener l) | Adds the specified mouse listener to receive mouse events from this component. |
void | addMouseMotionListener(MouseMotionListener l) | Adds the specified mouse motion listener to receive mouse motion events from this component. |
void | addMouseWheelListener(MouseWheelListener l) | Adds the specified mouse wheel listener to receive mouse wheel events from this component. |
void | addNotify() | Makes this Component displayable by connecting it to a native screen resource. |
void | addPropertyChangeListener(PropertyChangeListener listener) | 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 | applyComponentOrientation(ComponentOrientation orientation) | Sets the ComponentOrientation property of this component 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 Component. |
Rectangle | bounds() | Deprecated. As of JDK version 1.1, replaced by getBounds() . |
int | checkImage(Image image,ImageObserver observer) | Returns the status of the construction of a screen representation of the specified image. |
int | checkImage(Image image, int width, int height,ImageObserver observer) | Returns the status of the construction of a screen representation of the specified image. |
protectedAWTEvent | coalesceEvents(AWTEvent existingEvent,AWTEvent newEvent) | Potentially coalesce an event being posted with an existing event. |
boolean | contains(int x, int y) | Checks whether this component "contains" the specified point, where x andy are defined to be relative to the coordinate system of this component. |
boolean | contains(Point p) | Checks whether this component "contains" the specified point, where the point'sx andy coordinates are defined to be relative to the coordinate system of this component. |
Image | createImage(ImageProducer producer) | Creates an image from the specified image producer. |
Image | createImage(int width, int height) | Creates an off-screen drawable image to be used for double buffering. |
VolatileImage | createVolatileImage(int width, int height) | Creates a volatile off-screen drawable image to be used for double buffering. |
VolatileImage | createVolatileImage(int width, int height,ImageCapabilities caps) | Creates a volatile off-screen drawable image, with the given capabilities. |
void | deliverEvent(Event e) | Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e) . |
void | disable() | Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean) . |
protected void | disableEvents(long eventsToDisable) | Disables the events defined by the specified event mask parameter from being delivered to this component. |
void | dispatchEvent(AWTEvent e) | Dispatches an event to this component or one of its sub components. |
void | doLayout() | Prompts the layout manager to lay out this component. |
void | enable() | Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean) . |
void | enable(boolean b) | Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean) . |
protected void | enableEvents(long eventsToEnable) | Enables the events defined by the specified event mask parameter to be delivered to this component. |
void | enableInputMethods(boolean enable) | Enables or disables input method support for this component. |
protected void | firePropertyChange(String propertyName, boolean oldValue, boolean newValue) | Support for reporting bound property changes for boolean properties. |
void | firePropertyChange(String propertyName, byte oldValue, byte newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName, char oldValue, char newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName, double oldValue, double newValue) | Reports a bound property change. |
void | firePropertyChange(String propertyName, float oldValue, float newValue) | Reports a bound property change. |
protected void | firePropertyChange(String propertyName, int oldValue, int newValue) | Support for reporting bound property changes for integer properties. |
void | firePropertyChange(String propertyName, long oldValue, long newValue) | Reports a bound property change. |
protected void | firePropertyChange(String propertyName,Object oldValue,Object newValue) | Support for reporting bound property changes for Object properties. |
void | firePropertyChange(String propertyName, short oldValue, short newValue) | Reports a bound property change. |
AccessibleContext | getAccessibleContext() | Gets the AccessibleContext associated with thisComponent . |
float | getAlignmentX() | Returns the alignment along the x axis. |
float | getAlignmentY() | Returns the alignment along the y axis. |
Color | getBackground() | Gets the background color of this component. |
int | getBaseline(int width, int height) | Returns the baseline. |
Component.BaselineResizeBehavior | getBaselineResizeBehavior() | Returns an enum indicating how the baseline of the component changes as the size changes. |
Rectangle | getBounds() | Gets the bounds of this component in the form of a Rectangle object. |
Rectangle | getBounds(Rectangle rv) | Stores the bounds of this component into "return value"rv and returnrv. |
ColorModel | getColorModel() | Gets the instance of ColorModel used to display the component on the output device. |
Component | getComponentAt(int x, int y) | Determines if this component or one of its immediate subcomponents contains the (x, y) location, and if so, returns the containing component. |
Component | getComponentAt(Point p) | Returns the component or subcomponent that contains the specified point. |
ComponentListener[] | getComponentListeners() | Returns an array of all the component listeners registered on this component. |
ComponentOrientation | getComponentOrientation() | Retrieves the language-sensitive orientation that is to be used to order the elements or text within this component. |
Cursor | getCursor() | Gets the cursor set in the component. |
DropTarget | getDropTarget() | Gets the DropTarget associated with thisComponent . |
Container | getFocusCycleRootAncestor() | Returns the Container which is the focus cycle root of this Component's focus traversal cycle. |
FocusListener[] | getFocusListeners() | Returns an array of all the focus listeners registered on this component. |
Set<AWTKeyStroke> | getFocusTraversalKeys(int id) | Returns the Set of focus traversal keys for a given traversal operation for this Component. |
boolean | getFocusTraversalKeysEnabled() | Returns whether focus traversal keys are enabled for this Component. |
Font | getFont() | Gets the font of this component. |
FontMetrics | getFontMetrics(Font font) | Gets the font metrics for the specified font. |
Color | getForeground() | Gets the foreground color of this component. |
Graphics | getGraphics() | Creates a graphics context for this component. |
GraphicsConfiguration | getGraphicsConfiguration() | Gets the GraphicsConfiguration associated with thisComponent . |
int | getHeight() | Returns the current height of this component. |
HierarchyBoundsListener[] | getHierarchyBoundsListeners() | Returns an array of all the hierarchy bounds listeners registered on this component. |
HierarchyListener[] | getHierarchyListeners() | Returns an array of all the hierarchy listeners registered on this component. |
boolean | getIgnoreRepaint() | |
InputContext | getInputContext() | Gets the input context used by this component for handling the communication with input methods when text is entered in this component. |
InputMethodListener[] | getInputMethodListeners() | Returns an array of all the input method listeners registered on this component. |
InputMethodRequests | getInputMethodRequests() | Gets the input method request handler which supports requests from input methods for this component. |
KeyListener[] | getKeyListeners() | Returns an array of all the key listeners registered on this component. |
<T extendsEventListener> | getListeners(Class<T> listenerType) | Returns an array of all the objects currently registered as FooListener s upon thisComponent . |
Locale | getLocale() | Gets the locale of this component. |
Point | getLocation() | Gets the location of this component in the form of a point specifying the component's top-left corner. |
Point | getLocation(Point rv) | Stores the x,y origin of this component into "return value"rv and returnrv. |
Point | getLocationOnScreen() | Gets the location of this component in the form of a point specifying the component's top-left corner in the screen's coordinate space. |
Dimension | getMaximumSize() | Gets the maximum size of this component. |
Dimension | getMinimumSize() | Gets the minimum size of this component. |
MouseListener[] | getMouseListeners() | Returns an array of all the mouse listeners registered on this component. |
MouseMotionListener[] | getMouseMotionListeners() | Returns an array of all the mouse motion listeners registered on this component. |
Point | getMousePosition() | Returns the position of the mouse pointer in this Component 's coordinate space if theComponent is directly under the mouse pointer, otherwise returnsnull . |
MouseWheelListener[] | getMouseWheelListeners() | Returns an array of all the mouse wheel listeners registered on this component. |
String | getName() | Gets the name of the component. |
Container | getParent() | Gets the parent of this component. |
java.awt.peer.ComponentPeer | getPeer() | Deprecated. As of JDK version 1.1, programs should not directly manipulate peers; replaced by boolean isDisplayable() . |
Dimension | getPreferredSize() | Gets the preferred size of this component. |
PropertyChangeListener[] | getPropertyChangeListeners() | Returns an array of all the property change listeners registered on this component. |
PropertyChangeListener[] | getPropertyChangeListeners(String propertyName) | Returns an array of all the listeners which have been associated with the named property. |
Dimension | getSize() | Returns the size of this component in the form of a Dimension object. |
Dimension | getSize(Dimension rv) | Stores the width/height of this component into "return value"rv and returnrv. |
Toolkit | getToolkit() | Gets the toolkit of this component. |
Object | getTreeLock() | Gets this component's locking object (the object that owns the thread synchronization monitor) for AWT component-tree and layout operations. |
int | getWidth() | Returns the current width of this component. |
int | getX() | Returns the current x coordinate of the components origin. |
int | getY() | Returns the current y coordinate of the components origin. |
boolean | gotFocus(Event evt,Object what) | Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent). |
boolean | handleEvent(Event evt) | Deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent). |
boolean | hasFocus() | Returns true if thisComponent is the focus owner. |
void | hide() | Deprecated. As of JDK version 1.1, replaced by setVisible(boolean) . |
boolean | imageUpdate(Image img, int infoflags, int x, int y, int w, int h) | Repaints the component when the image has changed. |
boolean | inside(int x, int y) | Deprecated. As of JDK version 1.1, replaced by contains(int, int). |
void | invalidate() | Invalidates this component and its ancestors. |
boolean | isBackgroundSet() | Returns whether the background color has been explicitly set for this Component. |
boolean | isCursorSet() | Returns whether the cursor has been explicitly set for this Component. |
boolean | isDisplayable() | Determines whether this component is displayable. |
boolean | isDoubleBuffered() | Returns true if this component is painted to an offscreen image ("buffer") that's copied to the screen later. |
boolean | isEnabled() | Determines whether this component is enabled. |
boolean | isFocusable() | Returns whether this Component can be focused. |
boolean | isFocusCycleRoot(Container container) | Returns whether the specified Container is the focus cycle root of this Component's focus traversal cycle. |
boolean | isFocusOwner() | Returns true if thisComponent is the focus owner. |
boolean | isFocusTraversable() | Deprecated. As of 1.4, replaced by isFocusable() . |
boolean | isFontSet() | Returns whether the font has been explicitly set for this Component. |
boolean | isForegroundSet() | Returns whether the foreground color has been explicitly set for this Component. |
boolean | isLightweight() | A lightweight component doesn't have a native toolkit peer. |
boolean | isMaximumSizeSet() | Returns true if the maximum size has been set to a non- null value otherwise returns false. |
boolean | isMinimumSizeSet() | Returns whether or not setMinimumSize has been invoked with a non-null value. |
boolean | isOpaque() | Returns true if this component is completely opaque, returns false by default. |
boolean | isPreferredSizeSet() | Returns true if the preferred size has been set to a non- null value otherwise returns false. |
boolean | isShowing() | Determines whether this component is showing on screen. |
boolean | isValid() | Determines whether this component is valid. |
boolean | isVisible() | Determines whether this component should be visible when its parent is visible. |
boolean | keyDown(Event evt, int key) | Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent). |
boolean | keyUp(Event evt, int key) | Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent). |
void | layout() | Deprecated. As of JDK version 1.1, replaced by doLayout() . |
void | list() | Prints a listing of this component to the standard system output stream System.out . |
void | list(PrintStream out) | Prints a listing of this component to the specified output stream. |
void | list(PrintStream out, int indent) | Prints out a list, starting at the specified indentation, to the specified print stream. |
void | list(PrintWriter out) | Prints a listing to the specified print writer. |
void | list(PrintWriter out, int indent) | Prints out a list, starting at the specified indentation, to the specified print writer. |
Component | locate(int x, int y) | Deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int). |
Point | location() | Deprecated. As of JDK version 1.1, replaced by getLocation() . |
boolean | lostFocus(Event evt,Object what) | Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent). |
Dimension | minimumSize() | Deprecated. As of JDK version 1.1, replaced by getMinimumSize() . |
boolean | mouseDown(Event evt, int x, int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
boolean | mouseDrag(Event evt, int x, int y) | Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent). |
boolean | mouseEnter(Event evt, int x, int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
boolean | mouseExit(Event evt, int x, int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
boolean | mouseMove(Event evt, int x, int y) | Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent). |
boolean | mouseUp(Event evt, int x, int y) | Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
void | move(int x, int y) | Deprecated. As of JDK version 1.1, replaced by setLocation(int, int) . |
void | nextFocus() | Deprecated. As of JDK version 1.1, replaced by transferFocus(). |
void | paint(Graphics g) | Paints this component. |
void | paintAll(Graphics g) | Paints this component and all of its subcomponents. |
protectedString | paramString() | Returns a string representing the state of this component. |
boolean | postEvent(Event e) | Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent). |
Dimension | preferredSize() | Deprecated. As of JDK version 1.1, replaced by getPreferredSize() . |
boolean | prepareImage(Image image,ImageObserver observer) | Prepares an image for rendering on this component. |
boolean | prepareImage(Image image, int width, int height,ImageObserver observer) | Prepares an image for rendering on this component at the specified width and height. |
void | print(Graphics g) | Prints this component. |
void | printAll(Graphics g) | Prints this component and all of its subcomponents. |
protected void | processComponentEvent(ComponentEvent e) | Processes component events occurring on this component by dispatching them to any registered ComponentListener objects. |
protected void | processEvent(AWTEvent e) | Processes events occurring on this component. |
protected void | processFocusEvent(FocusEvent e) | Processes focus events occurring on this component by dispatching them to any registered FocusListener objects. |
protected void | processHierarchyBoundsEvent(HierarchyEvent e) | Processes hierarchy bounds events occurring on this component by dispatching them to any registered HierarchyBoundsListener objects. |
protected void | processHierarchyEvent(HierarchyEvent e) | Processes hierarchy events occurring on this component by dispatching them to any registered HierarchyListener objects. |
protected void | processInputMethodEvent(InputMethodEvent e) | Processes input method events occurring on this component by dispatching them to any registered InputMethodListener objects. |
protected void | processKeyEvent(KeyEvent e) | Processes key events occurring on this component by dispatching them to any registered KeyListener objects. |
protected void | processMouseEvent(MouseEvent e) | Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects. |
protected void | processMouseMotionEvent(MouseEvent e) | Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener objects. |
protected void | processMouseWheelEvent(MouseWheelEvent e) | Processes mouse wheel events occurring on this component by dispatching them to any registered MouseWheelListener objects. |
void | remove(MenuComponent popup) | Removes the specified popup menu from the component. |
void | removeComponentListener(ComponentListener l) | Removes the specified component listener so that it no longer receives component events from this component. |
void | removeFocusListener(FocusListener l) | Removes the specified focus listener so that it no longer receives focus events from this component. |
void | removeHierarchyBoundsListener(HierarchyBoundsListener l) | Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component. |
void | removeHierarchyListener(HierarchyListener l) | Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component. |
void | removeInputMethodListener(InputMethodListener l) | Removes the specified input method listener so that it no longer receives input method events from this component. |
void | removeKeyListener(KeyListener l) | Removes the specified key listener so that it no longer receives key events from this component. |
void | removeMouseListener(MouseListener l) | Removes the specified mouse listener so that it no longer receives mouse events from this component. |
void | removeMouseMotionListener(MouseMotionListener l) | Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component. |
void | removeMouseWheelListener(MouseWheelListener l) | Removes the specified mouse wheel listener so that it no longer receives mouse wheel events from this component. |
void | removeNotify() | Makes this Component undisplayable by destroying it native screen resource. |
void | removePropertyChangeListener(PropertyChangeListener listener) | Removes a PropertyChangeListener from the listener list. |
void | removePropertyChangeListener(String propertyName,PropertyChangeListener listener) | Removes a PropertyChangeListener from the listener list for a specific property. |
void | repaint() | Repaints this component. |
void | repaint(int x, int y, int width, int height) | Repaints the specified rectangle of this component. |
void | repaint(long tm) | Repaints the component. |
void | repaint(long tm, int x, int y, int width, int height) | Repaints the specified rectangle of this component within tm milliseconds. |
void | requestFocus() | Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. |
protected boolean | requestFocus(boolean temporary) | Requests that this Component get the input focus, and that thisComponent 's top-level ancestor become the focusedWindow . |
boolean | requestFocusInWindow() | Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. |
protected boolean | requestFocusInWindow(boolean temporary) | Requests that this Component get the input focus, if thisComponent 's top-level ancestor is already the focusedWindow . |
void | reshape(int x, int y, int width, int height) | Deprecated. As of JDK version 1.1, replaced by setBounds(int, int, int, int) . |
void | resize(Dimension d) | Deprecated. As of JDK version 1.1, replaced by setSize(Dimension) . |
void | resize(int width, int height) | Deprecated. As of JDK version 1.1, replaced by setSize(int, int) . |
void | revalidate() | Revalidates the component hierarchy up to the nearest validate root. |
void | setBackground(Color c) | Sets the background color of this component. |
void | setBounds(int x, int y, int width, int height) | Moves and resizes this component. |
void | setBounds(Rectangle r) | Moves and resizes this component to conform to the new bounding rectangle r . |
void | setComponentOrientation(ComponentOrientation o) | Sets the language-sensitive orientation that is to be used to order the elements or text within this component. |
void | setCursor(Cursor cursor) | Sets the cursor image to the specified cursor. |
void | setDropTarget(DropTarget dt) | Associate a DropTarget with this component. |
void | setEnabled(boolean b) | Enables or disables this component, depending on the value of the parameter b . |
void | setFocusable(boolean focusable) | Sets the focusable state of this Component to the specified value. |
void | setFocusTraversalKeys(int id,Set<? extendsAWTKeyStroke> keystrokes) | Sets the focus traversal keys for a given traversal operation for this Component. |
void | setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled) | Sets whether focus traversal keys are enabled for this Component. |
void | setFont(Font f) | Sets the font of this component. |
void | setForeground(Color c) | Sets the foreground color of this component. |
void | setIgnoreRepaint(boolean ignoreRepaint) | Sets whether or not paint messages received from the operating system should be ignored. |
void | setLocale(Locale l) | Sets the locale of this component. |
void | setLocation(int x, int y) | Moves this component to a new location. |
void | setLocation(Point p) | Moves this component to a new location. |
void | setMaximumSize(Dimension maximumSize) | Sets the maximum size of this component to a constant value. |
void | setMinimumSize(Dimension minimumSize) | Sets the minimum size of this component to a constant value. |
void | setName(String name) | Sets the name of the component to the specified string. |
void | setPreferredSize(Dimension preferredSize) | Sets the preferred size of this component to a constant value. |
void | setSize(Dimension d) | Resizes this component so that it has width d.width and heightd.height . |
void | setSize(int width, int height) | Resizes this component so that it has width width and heightheight . |
void | setVisible(boolean b) | Shows or hides this component depending on the value of parameter b . |
void | show() | Deprecated. As of JDK version 1.1, replaced by setVisible(boolean) . |
void | show(boolean b) | Deprecated. As of JDK version 1.1, replaced by setVisible(boolean) . |
Dimension | size() | Deprecated. As of JDK version 1.1, replaced by getSize() . |
String | toString() | Returns a string representation of this component and its values. |
void | transferFocus() | Transfers the focus to the next component, as though this Component were the focus owner. |
void | transferFocusBackward() | Transfers the focus to the previous component, as though this Component were the focus owner. |
void | transferFocusUpCycle() | Transfers the focus up one focus traversal cycle. |
void | update(Graphics g) | Updates this component. |
void | validate() | Validates this component. |
public static final float TOP_ALIGNMENT
getAlignmentY()
. Specifies an alignment to the top of the component.getAlignmentY()
,Constant Field Valuespublic static final float CENTER_ALIGNMENT
getAlignmentY
andgetAlignmentX
. Specifies an alignment to the center of the componentpublic static final float BOTTOM_ALIGNMENT
getAlignmentY
. Specifies an alignment to the bottom of the component.getAlignmentY()
,Constant Field Valuespublic static final float LEFT_ALIGNMENT
getAlignmentX
. Specifies an alignment to the left side of the component.getAlignmentX()
,Constant Field Valuespublic static final float RIGHT_ALIGNMENT
getAlignmentX
. Specifies an alignment to the right side of the component.getAlignmentX()
,Constant Field Valuesprotected AccessibleContext accessibleContext
AccessibleContext
associated with thisComponent
.protected Component()
Component
can be extended directly to create a lightweight component that does not utilize an opaque native window. A lightweight component must be hosted by a native container somewhere higher up in the component tree (for example, by aFrame
object).public String getName()
setName(java.lang.String)
public void setName(String name)
name
- the string that is to be this component's namegetName()
public Container getParent()
@Deprecatedpublic java.awt.peer.ComponentPeer getPeer()
boolean isDisplayable()
.public void setDropTarget(DropTarget dt)
DropTarget
with this component. TheComponent
will receive drops only if it is enabled.dt
- The DropTargetisEnabled()
public DropTarget getDropTarget()
DropTarget
associated with thisComponent
.public GraphicsConfiguration getGraphicsConfiguration()
GraphicsConfiguration
associated with thisComponent
. If theComponent
has not been assigned a specificGraphicsConfiguration
, theGraphicsConfiguration
of theComponent
object's top-level container is returned. If theComponent
has been created, but not yet added to aContainer
, this method returnsnull
.GraphicsConfiguration
used by thisComponent
ornull
public final Object getTreeLock()
public Toolkit getToolkit()
public boolean isValid()
true
if the component is valid,false
otherwisevalidate()
,invalidate()
public boolean isDisplayable()
A component is made displayable either when it is added to a displayable containment hierarchy or when its containment hierarchy is made displayable. A containment hierarchy is made displayable when its ancestor window is either packed or made visible.
A component is made undisplayable either when it is removed from a displayable containment hierarchy or when its containment hierarchy is made undisplayable. A containment hierarchy is made undisplayable when its ancestor window is disposed.
true
if the component is displayable,false
otherwiseContainer.add(Component)
,Window.pack()
,Window.show()
,Container.remove(Component)
,Window.dispose()
public boolean isVisible()
Frame
objects.true
if the component is visible,false
otherwisesetVisible(boolean)
public Point getMousePosition() throwsHeadlessException
Component
's coordinate space if theComponent
is directly under the mouse pointer, otherwise returnsnull
. If theComponent
is not showing on the screen, this method returnsnull
even if the mouse pointer is above the area where theComponent
would be displayed. If theComponent
is partially or fully obscured by otherComponent
s or native windows, this method returns a non-null value only if the mouse pointer is located above the unobscured part of theComponent
. ForContainer
s it returns a non-null value if the mouse is above theContainer
itself or above any of its descendants. UseContainer.getMousePosition(boolean)
if you need to exclude children.
Sometimes the exact mouse coordinates are not important, and the only thing that matters is whether a specificComponent
is under the mouse pointer. If the return value of this method isnull
, mouse pointer is not directly above theComponent
.
Component
, or nullHeadlessException
- if GraphicsEnvironment.isHeadless() returns trueisShowing()
,Container.getMousePosition(boolean)
public boolean isShowing()
Note: sometimes there is no way to detect whether theComponent
is actually visible to the user. This can happen when:
ScrollPane
but theComponent
is not currently in the scroll pane's view port.Component
is obscured by anotherComponent
orContainer
.true
if the component is showing,false
otherwisesetVisible(boolean)
public boolean isEnabled()
setEnabled
method.true
if the component is enabled,false
otherwisesetEnabled(boolean)
public void setEnabled(boolean b)
b
. An enabled component can respond to user input and generate events. Components are enabled initially by default.Note: Disabling a lightweight component does not prevent it from receiving MouseEvents.
Note: Disabling a heavyweight container prevents all components in this container from receiving any input events. But disabling a lightweight container affects only this container.
b
- Iftrue
, this component is enabled; otherwise this component is disabledisEnabled()
,isLightweight()
@Deprecatedpublic void enable()
setEnabled(boolean)
.@Deprecatedpublic void enable(boolean b)
setEnabled(boolean)
.@Deprecatedpublic void disable()
setEnabled(boolean)
.public boolean isDoubleBuffered()
public void enableInputMethods(boolean enable)
enable
- true to enable, false to disableprocessKeyEvent(java.awt.event.KeyEvent)
public void setVisible(boolean b)
b
.This method changes layout-related information, and therefore, invalidates the component hierarchy.
b
- iftrue
, shows this component; otherwise, hides this componentisVisible()
,invalidate()
@Deprecatedpublic void show()
setVisible(boolean)
.@Deprecatedpublic void show(boolean b)
setVisible(boolean)
.@Deprecatedpublic void hide()
setVisible(boolean)
.public Color getForeground()
setForeground(java.awt.Color)
public void setForeground(Color c)
c
- the color to become this component's foreground color; if this parameter isnull
then this component will inherit the foreground color of its parentgetForeground()
public boolean isForegroundSet()
false
, this Component is inheriting its foreground color from an ancestor.true
if the foreground color has been explicitly set for this Component;false
otherwise.public Color getBackground()
setBackground(java.awt.Color)
public void setBackground(Color c)
The background color affects each component differently and the parts of the component that are affected by the background color may differ between operating systems.
c
- the color to become this component's color; if this parameter isnull
, then this component will inherit the background color of its parentgetBackground()
public boolean isBackgroundSet()
false
, this Component is inheriting its background color from an ancestor.true
if the background color has been explicitly set for this Component;false
otherwise.public Font getFont()
getFont
in interface MenuContainer
setFont(java.awt.Font)
public void setFont(Font f)
This method changes layout-related information, and therefore, invalidates the component hierarchy.
f
- the font to become this component's font; if this parameter isnull
then this component will inherit the font of its parentgetFont()
,invalidate()
public boolean isFontSet()
false
, this Component is inheriting its font from an ancestor.true
if the font has been explicitly set for this Component;false
otherwise.public Locale getLocale()
IllegalComponentStateException
- if theComponent
does not have its own locale and has not yet been added to a containment hierarchy such that the locale can be determined from the containing parentsetLocale(java.util.Locale)
public void setLocale(Locale l)
This method changes layout-related information, and therefore, invalidates the component hierarchy.
l
- the locale to become this component's localegetLocale()
,invalidate()
public ColorModel getColorModel()
ColorModel
used to display the component on the output device.ColorModel
,ComponentPeer.getColorModel()
,Toolkit.getColorModel()
public Point getLocation()
Due to the asynchronous nature of native event handling, this method can return outdated values (for instance, after several calls ofsetLocation()
in rapid succession). For this reason, the recommended method of obtaining a component's position is withinjava.awt.event.ComponentListener.componentMoved()
, which is called after the operating system has finished moving the component.
Point
representing the top-left corner of the component's bounds in the coordinate space of the component's parentsetLocation(int, int)
,getLocationOnScreen()
public Point getLocationOnScreen()
Point
representing the top-left corner of the component's bounds in the coordinate space of the screenIllegalComponentStateException
- if the component is not showing on the screensetLocation(int, int)
,getLocation()
@Deprecatedpublic Point location()
getLocation()
.public void setLocation(int x, int y)
x
andy
parameters in the coordinate space of this component's parent.This method changes layout-related information, and therefore, invalidates the component hierarchy.
x
- thex-coordinate of the new location's top-left corner in the parent's coordinate spacey
- they-coordinate of the new location's top-left corner in the parent's coordinate spacegetLocation()
,setBounds(int, int, int, int)
,invalidate()
@Deprecatedpublic void move(int x, int y)
setLocation(int, int)
.public void setLocation(Point p)
p
. Pointp
is given in the parent's coordinate space.This method changes layout-related information, and therefore, invalidates the component hierarchy.
p
- the point defining the top-left corner of the new location, given in the coordinate space of this component's parentgetLocation()
,setBounds(int, int, int, int)
,invalidate()
public Dimension getSize()
Dimension
object. Theheight
field of theDimension
object contains this component's height, and thewidth
field of theDimension
object contains this component's width.Dimension
object that indicates the size of this componentsetSize(int, int)
@Deprecatedpublic Dimension size()
getSize()
.public void setSize(int width, int height)
width
and heightheight
.This method changes layout-related information, and therefore, invalidates the component hierarchy.
width
- the new width of this component in pixelsheight
- the new height of this component in pixelsgetSize()
,setBounds(int, int, int, int)
,invalidate()
@Deprecatedpublic void resize(int width, int height)
setSize(int, int)
.public void setSize(Dimension d)
d.width
and heightd.height
.This method changes layout-related information, and therefore, invalidates the component hierarchy.
d
- the dimension specifying the new size of this componentNullPointerException
- ifd
isnull
setSize(int, int)
,setBounds(int, int, int, int)
,invalidate()
@Deprecatedpublic void resize(Dimension d)
setSize(Dimension)
.public Rectangle getBounds()
Rectangle
object. The bounds specify this component's width, height, and location relative to its parent.setBounds(int, int, int, int)
,getLocation()
,getSize()
@Deprecatedpublic Rectangle bounds()
getBounds()
.public void setBounds(int x, int y, int width, int height)
x
andy
, and the new size is specified bywidth
andheight
.This method changes layout-related information, and therefore, invalidates the component hierarchy.
x
- the newx-coordinate of this componenty
- the newy-coordinate of this componentwidth
- the newwidth
of this componentheight
- the newheight
of this componentgetBounds()
,setLocation(int, int)
,setLocation(Point)
,setSize(int, int)
,setSize(Dimension)
,invalidate()
@Deprecatedpublic void reshape(int x, int y, int width, int height)
setBounds(int, int, int, int)
.public void setBounds(Rectangle r)
r
. This component's new position is specified byr.x
andr.y
, and its new size is specified byr.width
andr.height
This method changes layout-related information, and therefore, invalidates the component hierarchy.
r
- the new bounding rectangle for this componentNullPointerException
- ifr
isnull
getBounds()
,setLocation(int, int)
,setLocation(Point)
,setSize(int, int)
,setSize(Dimension)
,invalidate()
public int getX()
component.getBounds().x
, orcomponent.getLocation().x
because it doesn't cause any heap allocations.public int getY()
component.getBounds().y
, orcomponent.getLocation().y
because it doesn't cause any heap allocations.public int getWidth()
component.getBounds().width
, orcomponent.getSize().width
because it doesn't cause any heap allocations.public int getHeight()
component.getBounds().height
, orcomponent.getSize().height
because it doesn't cause any heap allocations.public Rectangle getBounds(Rectangle rv)
null
a newRectangle
is allocated. This version ofgetBounds
is useful if the caller wants to avoid allocating a newRectangle
object on the heap.rv
- the return value, modified to the components boundspublic Dimension getSize(Dimension rv)
null
a newDimension
object is allocated. This version ofgetSize
is useful if the caller wants to avoid allocating a newDimension
object on the heap.rv
- the return value, modified to the components sizepublic Point getLocation(Point rv)
null
a newPoint
is allocated. This version ofgetLocation
is useful if the caller wants to avoid allocating a newPoint
object on the heap.rv
- the return value, modified to the components locationpublic boolean isOpaque()
An opaque component paints every pixel within its rectangular region. A non-opaque component paints only some of its pixels, allowing the pixels underneath it to "show through". A component that does not fully paint its pixels therefore provides a degree of transparency.
Subclasses that guarantee to always completely paint their contents should override this method and return true.
isLightweight()
public boolean isLightweight()
Component
andContainer
, other than the ones defined in this package likeButton
orScrollbar
, are lightweight. All of the Swing components are lightweights. This method will always returnfalse
if this component is not displayable because it is impossible to determine the weight of an undisplayable component.
isDisplayable()
public void setPreferredSize(Dimension preferredSize)
getPreferredSize
will always return this value. Setting the preferred size tonull
restores the default behavior.preferredSize
- The new preferred size, or nullgetPreferredSize()
,isPreferredSizeSet()
public boolean isPreferredSizeSet()
null
value otherwise returns false.setPreferredSize
has been invoked with a non-null value.public Dimension getPreferredSize()
getMinimumSize()
,LayoutManager
@Deprecatedpublic Dimension preferredSize()
getPreferredSize()
.public void setMinimumSize(Dimension minimumSize)
getMinimumSize
will always return this value. Setting the minimum size tonull
restores the default behavior.minimumSize
- the new minimum size of this componentgetMinimumSize()
,isMinimumSizeSet()
public boolean isMinimumSizeSet()
setMinimumSize
has been invoked with a non-null value.setMinimumSize
has been invoked with a non-null value.public Dimension getMinimumSize()
getPreferredSize()
,LayoutManager
@Deprecatedpublic Dimension minimumSize()
getMinimumSize()
.public void setMaximumSize(Dimension maximumSize)
getMaximumSize
will always return this value. Setting the maximum size tonull
restores the default behavior.maximumSize
- aDimension
containing the desired maximum allowable sizegetMaximumSize()
,isMaximumSizeSet()
public boolean isMaximumSizeSet()
null
value otherwise returns false.maximumSize
is non-null
, false otherwisepublic Dimension getMaximumSize()
getMinimumSize()
,getPreferredSize()
,LayoutManager
public float getAlignmentX()
public float getAlignmentY()
public int getBaseline(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 thatLayoutManager
s should not align this component on its baseline. The default implementation returns -1. Subclasses that support baseline should override appropriately. If a value >= 0 is returned, then the component has a valid baseline for any size >= the minimum size andgetBaselineResizeBehavior
can be used to determine how the baseline changes with size.
width
- the width to get the baseline forheight
- the height to get the baseline forIllegalArgumentException
- if width or height is < 0getBaselineResizeBehavior()
,FontMetrics
public Component.BaselineResizeBehavior getBaselineResizeBehavior()
The default implementation returnsBaselineResizeBehavior.OTHER
. Subclasses that have a baseline should override appropriately. Subclasses should never returnnull
; if the baseline can not be calculated returnBaselineResizeBehavior.OTHER
. Callers should first ask for the baseline usinggetBaseline
and if a value >= 0 is returned use this method. It is acceptable for this method to return a value other thanBaselineResizeBehavior.OTHER
even ifgetBaseline
returns a value less than 0.
getBaseline(int, int)
public void doLayout()
validate()
,LayoutManager
@Deprecatedpublic void layout()
doLayout()
.public void validate()
The meaning of the termvalidating is defined by the ancestors of this class. SeeContainer.validate()
for more details.
invalidate()
,doLayout()
,LayoutManager
,Container.validate()
public void invalidate()
By default, all the ancestors of the component up to the top-most container of the hierarchy are marked invalid. If thejava.awt.smartInvalidate
system property is set totrue
, invalidation stops on the nearest validate root of this component. Marking a containerinvalid indicates that the container needs to be laid out.
This method is called automatically when any layout-related information changes (e.g. setting the bounds of the component, or adding the component to a container).
This method might be called often, so it should work fast.
validate()
,doLayout()
,LayoutManager
,Container.isValidateRoot()
public void revalidate()
This method first invalidates the component hierarchy starting from this component up to the nearest validate root. Afterwards, the component hierarchy is validated starting from the nearest validate root.
This is a convenience method supposed to help application developers avoid looking for validate roots manually. Basically, it's equivalent to first calling theinvalidate()
method on this component, and then calling thevalidate()
method on the nearest validate root.
Container.isValidateRoot()
public Graphics getGraphics()
null
if this component is currently not displayable.null
if it has nonepaint(java.awt.Graphics)
public FontMetrics getFontMetrics(Font font)
FontRenderContext
and this method does not provide one, it can return only metrics for the default render context which may not match that used when rendering on the Component ifGraphics2D
functionality is being used. Instead metrics can be obtained at rendering time by callingGraphics.getFontMetrics()
or text measurement APIs on theFont
class.font
- the font for which font metrics is to be obtainedfont
getFont()
,getPeer()
,ComponentPeer.getFontMetrics(Font)
,Toolkit.getFontMetrics(Font)
public void setCursor(Cursor cursor)
contains
method for this component returns true for the current cursor location, and this Component is visible, displayable, and enabled. Setting the cursor of aContainer
causes that cursor to be displayed within all of the container's subcomponents, except for those that have a non-null
cursor.The method may have no visual effect if the Java platform implementation and/or the native system do not support changing the mouse cursor shape.
cursor
- One of the constants defined by theCursor
class; if this parameter isnull
then this component will inherit the cursor of its parentisEnabled()
,isShowing()
,getCursor()
,contains(int, int)
,Toolkit.createCustomCursor(java.awt.Image, java.awt.Point, java.lang.String)
,Cursor
public Cursor getCursor()
Cursor.DEFAULT_CURSOR
is returned.setCursor(java.awt.Cursor)
public boolean isCursorSet()
false
, this Component is inheriting its cursor from an ancestor.true
if the cursor has been explicitly set for this Component;false
otherwise.public void paint(Graphics g)
This method is called when the contents of the component should be painted; such as when the component is first being shown or is damaged and in need of repair. The clip rectangle in theGraphics
parameter is set to the area which needs to be painted. Subclasses ofComponent
that override this method need not callsuper.paint(g)
.
For performance reasons,Component
s with zero width or height aren't considered to need painting when they are first shown, and also aren't considered to need repair.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
g
- the graphics context to use for paintingupdate(java.awt.Graphics)
public void update(Graphics g)
If this component is not a lightweight component, the AWT calls theupdate
method in response to a call torepaint
. You can assume that the background is not cleared.
Theupdate
method ofComponent
calls this component'spaint
method to redraw this component. This method is commonly overridden by subclasses which need to do additional work in response to a call torepaint
. Subclasses of Component that override this method should either callsuper.update(g)
, or callpaint(g)
directly from theirupdate
method.
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
g
- the specified context to use for updatingpaint(java.awt.Graphics)
,repaint()
public void paintAll(Graphics g)
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
g
- the graphics context to use for paintingpaint(java.awt.Graphics)
public void repaint()
If this component is a lightweight component, this method causes a call to this component'spaint
method as soon as possible. Otherwise, this method causes a call to this component'supdate
method as soon as possible.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
update(Graphics)
public void repaint(long tm)
paint
withintm
milliseconds.Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
tm
- maximum time in milliseconds before updatepaint(java.awt.Graphics)
,update(Graphics)
public void repaint(int x, int y, int width, int height)
If this component is a lightweight component, this method causes a call to this component'spaint
method as soon as possible. Otherwise, this method causes a call to this component'supdate
method as soon as possible.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
x
- thex coordinatey
- they coordinatewidth
- the widthheight
- the heightupdate(Graphics)
public void repaint(long tm, int x, int y, int width, int height)
tm
milliseconds. If this component is a lightweight component, this method causes a call to this component'spaint
method. Otherwise, this method causes a call to this component'supdate
method.
Note: For more information on the paint mechanisms utilitized by AWT and Swing, including information on how to write the most efficient painting code, seePainting in AWT and Swing.
tm
- maximum time in milliseconds before updatex
- thex coordinatey
- they coordinatewidth
- the widthheight
- the heightupdate(Graphics)
public void print(Graphics g)
The default implementation of this method calls thepaint
method.
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
g
- the graphics context to use for printingpaint(Graphics)
public void printAll(Graphics g)
The origin of the graphics context, its (0
, 0
) coordinate point, is the top-left corner of this component. The clipping region of the graphics context is the bounding rectangle of this component.
g
- the graphics context to use for printingprint(Graphics)
public boolean imageUpdate(Image img, int infoflags, int x, int y, int w, int h)
imageUpdate
method of anImageObserver
is called when more information about an image which had been previously requested using an asynchronous routine such as thedrawImage
method ofGraphics
becomes available. See the definition ofimageUpdate
for more information on this method and its arguments. TheimageUpdate
method ofComponent
incrementally draws an image on the component as more of the bits of the image are available.
If the system propertyawt.image.incrementaldraw
is missing or has the valuetrue
, the image is incrementally drawn. If the system property has any other value, then the image is not drawn until it has been completely loaded.
Also, if incremental drawing is in effect, the value of the system propertyawt.image.redrawrate
is interpreted as an integer to give the maximum redraw rate, in milliseconds. If the system property is missing or cannot be interpreted as an integer, the redraw rate is once every 100ms.
The interpretation of thex
,y
,width
, andheight
arguments depends on the value of theinfoflags
argument.
imageUpdate
in interface ImageObserver
img
- the image being observedinfoflags
- seeimageUpdate
for more informationx
- thex coordinatey
- they coordinatew
- the widthh
- the heightfalse
if the infoflags indicate that the image is completely loaded;true
otherwise.ImageObserver
,Graphics.drawImage(Image, int, int, Color, java.awt.image.ImageObserver)
,Graphics.drawImage(Image, int, int, java.awt.image.ImageObserver)
,Graphics.drawImage(Image, int, int, int, int, Color, java.awt.image.ImageObserver)
,Graphics.drawImage(Image, int, int, int, int, java.awt.image.ImageObserver)
,ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)
public Image createImage(ImageProducer producer)
producer
- the image producerpublic Image createImage(int width, int height)
width
- the specified widthheight
- the specified heightnull
if the component is not displayable. This will always happen ifGraphicsEnvironment.isHeadless()
returnstrue
.isDisplayable()
,GraphicsEnvironment.isHeadless()
public VolatileImage createVolatileImage(int width, int height)
width
- the specified width.height
- the specified height.null
if the component is not displayable. This will always happen ifGraphicsEnvironment.isHeadless()
returnstrue
.VolatileImage
,isDisplayable()
,GraphicsEnvironment.isHeadless()
public VolatileImage createVolatileImage(int width, int height,ImageCapabilities caps) throwsAWTException
VolatileImage
interface.width
- the specified width.height
- the specified height.caps
- the image capabilitiesAWTException
- if an image with the specified capabilities cannot be createdVolatileImage
public boolean prepareImage(Image image,ImageObserver observer)
image
- theImage
for which to prepare a screen representationobserver
- theImageObserver
object to be notified as the image is being preparedtrue
if the image has already been fully prepared;false
otherwisepublic boolean prepareImage(Image image, int width, int height,ImageObserver observer)
The image data is downloaded asynchronously in another thread, and an appropriately scaled screen representation of the image is generated.
image
- the instance ofImage
for which to prepare a screen representationwidth
- the width of the desired screen representationheight
- the height of the desired screen representationobserver
- theImageObserver
object to be notified as the image is being preparedtrue
if the image has already been fully prepared;false
otherwiseImageObserver
public int checkImage(Image image,ImageObserver observer)
This method does not cause the image to begin loading. An application must use theprepareImage
method to force the loading of an image.
Information on the flags returned by this method can be found with the discussion of theImageObserver
interface.
image
- theImage
object whose status is being checkedobserver
- theImageObserver
object to be notified as the image is being preparedImageObserver
flags indicating what information about the image is currently availableprepareImage(Image, int, int, java.awt.image.ImageObserver)
,Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver)
,ImageObserver
public int checkImage(Image image, int width, int height,ImageObserver observer)
This method does not cause the image to begin loading. An application must use theprepareImage
method to force the loading of an image.
ThecheckImage
method ofComponent
calls its peer'scheckImage
method to calculate the flags. If this component does not yet have a peer, the component's toolkit'scheckImage
method is called instead.
Information on the flags returned by this method can be found with the discussion of theImageObserver
interface.
image
- theImage
object whose status is being checkedwidth
- the width of the scaled version whose status is to be checkedheight
- the height of the scaled version whose status is to be checkedobserver
- theImageObserver
object to be notified as the image is being preparedImageObserver
flags indicating what information about the image is currently availableprepareImage(Image, int, int, java.awt.image.ImageObserver)
,Toolkit.checkImage(Image, int, int, java.awt.image.ImageObserver)
,ImageObserver
public void setIgnoreRepaint(boolean ignoreRepaint)
This is useful, for example, if running under full-screen mode and better performance is desired, or if page-flipping is used as the buffer strategy.
public boolean getIgnoreRepaint()
setIgnoreRepaint(boolean)
public boolean contains(int x, int y)
x
andy
are defined to be relative to the coordinate system of this component.x
- thex coordinate of the pointy
- they coordinate of the pointgetComponentAt(int, int)
@Deprecatedpublic boolean inside(int x, int y)
public boolean contains(Point p)
p
- the pointNullPointerException
- ifp
isnull
getComponentAt(Point)
public Component getComponentAt(int x, int y)
Thelocate
method ofComponent
simply returns the component itself if the (x, y) coordinate location is inside its bounding box, andnull
otherwise.
x
- thex coordinatey
- they coordinatenull
if the location is outside this componentcontains(int, int)
@Deprecatedpublic Component locate(int x, int y)
public Component getComponentAt(Point p)
p
- the pointcontains(int, int)
@Deprecatedpublic void deliverEvent(Event e)
dispatchEvent(AWTEvent e)
.public final void dispatchEvent(AWTEvent e)
processEvent
before returning for 1.1-style events which have been enabled for theComponent
.e
- the event@Deprecatedpublic boolean postEvent(Event e)
postEvent
in interface MenuContainer
public void addComponentListener(ComponentListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the component listenerComponentEvent
,ComponentListener
,removeComponentListener(java.awt.event.ComponentListener)
,getComponentListeners()
public void removeComponentListener(ComponentListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the component listenerComponentEvent
,ComponentListener
,addComponentListener(java.awt.event.ComponentListener)
,getComponentListeners()
public ComponentListener[] getComponentListeners()
ComponentListener
s of this component or an empty array if no component listeners are currently registeredaddComponentListener(java.awt.event.ComponentListener)
,removeComponentListener(java.awt.event.ComponentListener)
public void addFocusListener(FocusListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the focus listenerFocusEvent
,FocusListener
,removeFocusListener(java.awt.event.FocusListener)
,getFocusListeners()
public void removeFocusListener(FocusListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the focus listenerFocusEvent
,FocusListener
,addFocusListener(java.awt.event.FocusListener)
,getFocusListeners()
public FocusListener[] getFocusListeners()
FocusListener
s or an empty array if no component listeners are currently registeredaddFocusListener(java.awt.event.FocusListener)
,removeFocusListener(java.awt.event.FocusListener)
public void addHierarchyListener(HierarchyListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the hierarchy listenerHierarchyEvent
,HierarchyListener
,removeHierarchyListener(java.awt.event.HierarchyListener)
,getHierarchyListeners()
public void removeHierarchyListener(HierarchyListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the hierarchy listenerHierarchyEvent
,HierarchyListener
,addHierarchyListener(java.awt.event.HierarchyListener)
,getHierarchyListeners()
public HierarchyListener[] getHierarchyListeners()
HierarchyListener
s or an empty array if no hierarchy listeners are currently registeredaddHierarchyListener(java.awt.event.HierarchyListener)
,removeHierarchyListener(java.awt.event.HierarchyListener)
public void addHierarchyBoundsListener(HierarchyBoundsListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the hierarchy bounds listenerHierarchyEvent
,HierarchyBoundsListener
,removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,getHierarchyBoundsListeners()
public void removeHierarchyBoundsListener(HierarchyBoundsListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the hierarchy bounds listenerHierarchyEvent
,HierarchyBoundsListener
,addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,getHierarchyBoundsListeners()
public HierarchyBoundsListener[] getHierarchyBoundsListeners()
HierarchyBoundsListener
s or an empty array if no hierarchy bounds listeners are currently registeredaddHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
public void addKeyListener(KeyListener l)
Refer toAWT Threading Issues for details on AWT's threading model.
l
- the key listener.KeyEvent
,KeyListener
,removeKeyListener(java.awt.event.KeyListener)
,getKeyListeners()
public void removeKeyListener(KeyListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the key listenerKeyEvent
,KeyListener
,addKeyListener(java.awt.event.KeyListener)
,getKeyListeners()
public KeyListener[] getKeyListeners()
KeyListener
s or an empty array if no key listeners are currently registeredaddKeyListener(java.awt.event.KeyListener)
,removeKeyListener(java.awt.event.KeyListener)
public void addMouseListener(MouseListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the mouse listenerMouseEvent
,MouseListener
,removeMouseListener(java.awt.event.MouseListener)
,getMouseListeners()
public void removeMouseListener(MouseListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the mouse listenerMouseEvent
,MouseListener
,addMouseListener(java.awt.event.MouseListener)
,getMouseListeners()
public MouseListener[] getMouseListeners()
MouseListener
s or an empty array if no mouse listeners are currently registeredaddMouseListener(java.awt.event.MouseListener)
,removeMouseListener(java.awt.event.MouseListener)
public void addMouseMotionListener(MouseMotionListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the mouse motion listenerMouseEvent
,MouseMotionListener
,removeMouseMotionListener(java.awt.event.MouseMotionListener)
,getMouseMotionListeners()
public void removeMouseMotionListener(MouseMotionListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the mouse motion listenerMouseEvent
,MouseMotionListener
,addMouseMotionListener(java.awt.event.MouseMotionListener)
,getMouseMotionListeners()
public MouseMotionListener[] getMouseMotionListeners()
MouseMotionListener
s or an empty array if no mouse motion listeners are currently registeredaddMouseMotionListener(java.awt.event.MouseMotionListener)
,removeMouseMotionListener(java.awt.event.MouseMotionListener)
public void addMouseWheelListener(MouseWheelListener l)
For information on how mouse wheel events are dispatched, see the class description forMouseWheelEvent
.
If l isnull
, no exception is thrown and no action is performed.
Refer toAWT Threading Issues for details on AWT's threading model.
l
- the mouse wheel listenerMouseWheelEvent
,MouseWheelListener
,removeMouseWheelListener(java.awt.event.MouseWheelListener)
,getMouseWheelListeners()
public void removeMouseWheelListener(MouseWheelListener l)
Refer toAWT Threading Issues for details on AWT's threading model.
l
- the mouse wheel listener.MouseWheelEvent
,MouseWheelListener
,addMouseWheelListener(java.awt.event.MouseWheelListener)
,getMouseWheelListeners()
public MouseWheelListener[] getMouseWheelListeners()
MouseWheelListener
s or an empty array if no mouse wheel listeners are currently registeredaddMouseWheelListener(java.awt.event.MouseWheelListener)
,removeMouseWheelListener(java.awt.event.MouseWheelListener)
public void addInputMethodListener(InputMethodListener l)
getInputMethodRequests
to return anInputMethodRequests
instance. If listenerl
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the input method listenerInputMethodEvent
,InputMethodListener
,removeInputMethodListener(java.awt.event.InputMethodListener)
,getInputMethodListeners()
,getInputMethodRequests()
public void removeInputMethodListener(InputMethodListener l)
l
isnull
, no exception is thrown and no action is performed.Refer toAWT Threading Issues for details on AWT's threading model.
l
- the input method listenerInputMethodEvent
,InputMethodListener
,addInputMethodListener(java.awt.event.InputMethodListener)
,getInputMethodListeners()
public InputMethodListener[] getInputMethodListeners()
InputMethodListener
s or an empty array if no input method listeners are currently registeredaddInputMethodListener(java.awt.event.InputMethodListener)
,removeInputMethodListener(java.awt.event.InputMethodListener)
public <T extendsEventListener> T[] getListeners(Class<T> listenerType)
FooListener
s upon thisComponent
.FooListener
s are registered using theaddFooListener
method. You can specify thelistenerType
argument with a class literal, such asFooListener.class
. For example, you can query aComponent
c
for its mouse listeners with the following code:
MouseListener[] mls = (MouseListener[])(c.getListeners(MouseListener.class));If no such listeners exist, this method returns an empty array.
listenerType
- the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
FooListener
s on this component, or an empty array if no such listeners have been addedClassCastException
- iflistenerType
doesn't specify a class or interface that implementsjava.util.EventListener
NullPointerException
- iflistenerType
isnull
getComponentListeners()
,getFocusListeners()
,getHierarchyListeners()
,getHierarchyBoundsListeners()
,getKeyListeners()
,getMouseListeners()
,getMouseMotionListeners()
,getMouseWheelListeners()
,getInputMethodListeners()
,getPropertyChangeListeners()
public InputMethodRequests getInputMethodRequests()
InputMethodRequests
instance. At the same time, it also has to handle input method events.null
by defaultaddInputMethodListener(java.awt.event.InputMethodListener)
public InputContext getInputContext()
null
if no context can be determinedprotected final void enableEvents(long eventsToEnable)
Event types are automatically enabled when a listener for that event type is added to the component.
This method only needs to be invoked by subclasses ofComponent
which desire to have the specified event types delivered toprocessEvent
regardless of whether or not a listener is registered.
eventsToEnable
- the event mask defining the event typesprocessEvent(java.awt.AWTEvent)
,disableEvents(long)
,AWTEvent
protected final void disableEvents(long eventsToDisable)
eventsToDisable
- the event mask defining the event typesenableEvents(long)
protected AWTEvent coalesceEvents(AWTEvent existingEvent,AWTEvent newEvent)
EventQueue.postEvent
if an event with the same ID as the event to be posted is found in the queue (both events must have this component as their source). This method either returns a coalesced event which replaces the existing event (and the new event is then discarded), ornull
to indicate that no combining should be done (add the second event to the end of the queue). Either event parameter may be modified and returned, as the other one is discarded unlessnull
is returned. This implementation ofcoalesceEvents
coalesces two event types: mouse move (and drag) events, and paint (and update) events. For mouse move events the last event is always returned, causing intermediate moves to be discarded. For paint events, the new event is coalesced into a complexRepaintArea
in the peer. The newAWTEvent
is always returned.
existingEvent
- the event already on theEventQueue
newEvent
- the event being posted to theEventQueue
null
indicating that no coalescing was doneprotected void processEvent(AWTEvent e)
process<event type>Event
method for the given class of event.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the eventprocessComponentEvent(java.awt.event.ComponentEvent)
,processFocusEvent(java.awt.event.FocusEvent)
,processKeyEvent(java.awt.event.KeyEvent)
,processMouseEvent(java.awt.event.MouseEvent)
,processMouseMotionEvent(java.awt.event.MouseEvent)
,processInputMethodEvent(java.awt.event.InputMethodEvent)
,processHierarchyEvent(java.awt.event.HierarchyEvent)
,processMouseWheelEvent(java.awt.event.MouseWheelEvent)
protected void processComponentEvent(ComponentEvent e)
ComponentListener
objects.This method is not called unless component events are enabled for this component. Component events are enabled when one of the following occurs:
ComponentListener
object is registered viaaddComponentListener
.enableEvents
.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the component eventComponentEvent
,ComponentListener
,addComponentListener(java.awt.event.ComponentListener)
,enableEvents(long)
protected void processFocusEvent(FocusEvent e)
FocusListener
objects.This method is not called unless focus events are enabled for this component. Focus events are enabled when one of the following occurs:
FocusListener
object is registered viaaddFocusListener
.enableEvents
. If focus events are enabled for aComponent
, the currentKeyboardFocusManager
determines whether or not a focus event should be dispatched to registeredFocusListener
objects. If the events are to be dispatched, theKeyboardFocusManager
calls theComponent
'sdispatchEvent
method, which results in a call to theComponent
'sprocessFocusEvent
method.
If focus events are enabled for aComponent
, calling theComponent
'sdispatchEvent
method with aFocusEvent
as the argument will result in a call to theComponent
'sprocessFocusEvent
method regardless of the currentKeyboardFocusManager
.
Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the focus eventFocusEvent
,FocusListener
,KeyboardFocusManager
,addFocusListener(java.awt.event.FocusListener)
,enableEvents(long)
,dispatchEvent(java.awt.AWTEvent)
protected void processKeyEvent(KeyEvent e)
KeyListener
objects.This method is not called unless key events are enabled for this component. Key events are enabled when one of the following occurs:
KeyListener
object is registered viaaddKeyListener
.enableEvents
. If key events are enabled for aComponent
, the currentKeyboardFocusManager
determines whether or not a key event should be dispatched to registeredKeyListener
objects. TheDefaultKeyboardFocusManager
will not dispatch key events to aComponent
that is not the focus owner or is not showing.
As of J2SE 1.4,KeyEvent
s are redirected to the focus owner. Please see theFocus Specification for further information.
Calling aComponent
'sdispatchEvent
method with aKeyEvent
as the argument will result in a call to theComponent
'sprocessKeyEvent
method regardless of the currentKeyboardFocusManager
as long as the component is showing, focused, and enabled, and key events are enabled on it.
If the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the key eventKeyEvent
,KeyListener
,KeyboardFocusManager
,DefaultKeyboardFocusManager
,processEvent(java.awt.AWTEvent)
,dispatchEvent(java.awt.AWTEvent)
,addKeyListener(java.awt.event.KeyListener)
,enableEvents(long)
,isShowing()
protected void processMouseEvent(MouseEvent e)
MouseListener
objects.This method is not called unless mouse events are enabled for this component. Mouse events are enabled when one of the following occurs:
MouseListener
object is registered viaaddMouseListener
.enableEvents
.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the mouse eventMouseEvent
,MouseListener
,addMouseListener(java.awt.event.MouseListener)
,enableEvents(long)
protected void processMouseMotionEvent(MouseEvent e)
MouseMotionListener
objects.This method is not called unless mouse motion events are enabled for this component. Mouse motion events are enabled when one of the following occurs:
MouseMotionListener
object is registered viaaddMouseMotionListener
.enableEvents
.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the mouse motion eventMouseEvent
,MouseMotionListener
,addMouseMotionListener(java.awt.event.MouseMotionListener)
,enableEvents(long)
protected void processMouseWheelEvent(MouseWheelEvent e)
MouseWheelListener
objects.This method is not called unless mouse wheel events are enabled for this component. Mouse wheel events are enabled when one of the following occurs:
MouseWheelListener
object is registered viaaddMouseWheelListener
.enableEvents
. For information on how mouse wheel events are dispatched, see the class description forMouseWheelEvent
.
Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the mouse wheel eventMouseWheelEvent
,MouseWheelListener
,addMouseWheelListener(java.awt.event.MouseWheelListener)
,enableEvents(long)
protected void processInputMethodEvent(InputMethodEvent e)
InputMethodListener
objects.This method is not called unless input method events are enabled for this component. Input method events are enabled when one of the following occurs:
InputMethodListener
object is registered viaaddInputMethodListener
.enableEvents
.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the input method eventInputMethodEvent
,InputMethodListener
,addInputMethodListener(java.awt.event.InputMethodListener)
,enableEvents(long)
protected void processHierarchyEvent(HierarchyEvent e)
HierarchyListener
objects.This method is not called unless hierarchy events are enabled for this component. Hierarchy events are enabled when one of the following occurs:
HierarchyListener
object is registered viaaddHierarchyListener
.enableEvents
.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the hierarchy eventHierarchyEvent
,HierarchyListener
,addHierarchyListener(java.awt.event.HierarchyListener)
,enableEvents(long)
protected void processHierarchyBoundsEvent(HierarchyEvent e)
HierarchyBoundsListener
objects.This method is not called unless hierarchy bounds events are enabled for this component. Hierarchy bounds events are enabled when one of the following occurs:
HierarchyBoundsListener
object is registered viaaddHierarchyBoundsListener
.enableEvents
.Note that if the event parameter isnull
the behavior is unspecified and may result in an exception.
e
- the hierarchy eventHierarchyEvent
,HierarchyBoundsListener
,addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
,enableEvents(long)
@Deprecatedpublic boolean handleEvent(Event evt)
@Deprecatedpublic boolean mouseDown(Event evt, int x, int y)
@Deprecatedpublic boolean mouseDrag(Event evt, int x, int y)
@Deprecatedpublic boolean mouseUp(Event evt, int x, int y)
@Deprecatedpublic boolean mouseMove(Event evt, int x, int y)
@Deprecatedpublic boolean mouseEnter(Event evt, int x, int y)
@Deprecatedpublic boolean mouseExit(Event evt, int x, int y)
@Deprecatedpublic boolean keyDown(Event evt, int key)
@Deprecatedpublic boolean keyUp(Event evt, int key)
@Deprecatedpublic boolean action(Event evt,Object what)
public void addNotify()
Component
displayable by connecting it to a native screen resource. This method is called internally by the toolkit and should not be called directly by programs.This method changes layout-related information, and therefore, invalidates the component hierarchy.
isDisplayable()
,removeNotify()
,invalidate()
public void removeNotify()
Component
undisplayable by destroying it native screen resource. This method is called by the toolkit internally and should not be called directly by programs. Code overriding this method should callsuper.removeNotify
as the first line of the overriding method.
isDisplayable()
,addNotify()
@Deprecatedpublic boolean gotFocus(Event evt,Object what)
@Deprecatedpublic boolean lostFocus(Event evt,Object what)
@Deprecatedpublic boolean isFocusTraversable()
isFocusable()
.Component
can become the focus owner.true
if thisComponent
is focusable;false
otherwisesetFocusable(boolean)
public boolean isFocusable()
true
if this Component is focusable;false
otherwise.setFocusable(boolean)
public void setFocusable(boolean focusable)
focusable
- indicates whether this Component is focusableisFocusable()
public void setFocusTraversalKeys(int id,Set<? extendsAWTKeyStroke> keystrokes)
The default values for a Component'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.
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 |
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 Component. 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 Component inherits the Set from its parent. If all ancestors of this Component have null specified for the Set, then the current KeyboardFocusManager's default Set is used.
This method may throw aClassCastException
if anyObject
inkeystrokes
is not anAWTKeyStroke
.
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSkeystrokes
- the Set of AWTKeyStroke for the specified operationIllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_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 ComponentgetFocusTraversalKeys(int)
,KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
public Set<AWTKeyStroke> getFocusTraversalKeys(int id)
setFocusTraversalKeys
for a full description of each key.)If a Set of traversal keys has not been explicitly defined for this Component, then this Component's parent's Set is returned. If no Set has been explicitly defined for any of this Component's ancestors, then the current KeyboardFocusManager's default Set is returned.
id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSIllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSsetFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS
,KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
public boolean areFocusTraversalKeysSet(int id)
false
, this Component is inheriting the Set from an ancestor, or from the current KeyboardFocusManager.id
- one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYStrue
if the the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component;false
otherwise.IllegalArgumentException
- if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYSpublic void setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)
focusTraversalKeysEnabled
- whether focus traversal keys are enabled for this ComponentgetFocusTraversalKeysEnabled()
,setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,getFocusTraversalKeys(int)
public boolean getFocusTraversalKeysEnabled()
setFocusTraversalKeysEnabled(boolean)
,setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>)
,getFocusTraversalKeys(int)
public void requestFocus()
This method cannot be used to set the focus owner to no Component at all. UseKeyboardFocusManager.clearGlobalFocusOwner()
instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to userequestFocusInWindow
when possible.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the otherrequestFocus
methods ofComponent
being invoked.
protected boolean requestFocus(boolean temporary)
Component
get the input focus, and that thisComponent
's top-level ancestor become the focusedWindow
. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event. If this request is denied because this component's top-level window cannot become the focused window, the request will be remembered and will be granted when the window is later focused by the user. This method returns a boolean value. Iffalse
is returned, the request isguaranteed to fail. Iftrue
is returned, the request will succeedunless it is vetoed, or an extraordinary event, such as disposal of the component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value oftrue
indicates that the request is likely to succeed, developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no component at all. UseKeyboardFocusManager.clearGlobalFocusOwner
instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to userequestFocusInWindow
when possible.
Every effort will be made to ensure thatFocusEvent
s generated as a result of this request will have the specified temporary value. However, because specifying an arbitrary temporary state may not be implementable on all native windowing systems, correct behavior for this method can be guaranteed only for lightweightComponent
s. This method is not intended for general use, but exists instead as a hook for lightweight component libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the otherrequestFocus
methods ofComponent
being invoked.
temporary
- true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see theFocus Specificationfalse
if the focus change request is guaranteed to fail;true
if it is likely to succeedFocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
public boolean requestFocusInWindow()
This method returns a boolean value. Iffalse
is returned, the request isguaranteed to fail. Iftrue
is returned, the request will succeedunless it is vetoed, or an extraordinary event, such as disposal of the Component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value oftrue
indicates that the request is likely to succeed, developers must never assume that this Component is the focus owner until this Component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no Component at all. UseKeyboardFocusManager.clearGlobalFocusOwner()
instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method overrequestFocus
when possible. Code which relies onrequestFocus
may exhibit different focus behavior on different platforms.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the otherrequestFocus
methods ofComponent
being invoked.
false
if the focus change request is guaranteed to fail;true
if it is likely to succeedrequestFocus()
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
protected boolean requestFocusInWindow(boolean temporary)
Component
get the input focus, if thisComponent
's top-level ancestor is already the focusedWindow
. This component must be displayable, focusable, visible and all of its ancestors (with the exception of the top-level Window) must be visible for the request to be granted. Every effort will be made to honor the request; however, in some cases it may be impossible to do so. Developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event. This method returns a boolean value. Iffalse
is returned, the request isguaranteed to fail. Iftrue
is returned, the request will succeedunless it is vetoed, or an extraordinary event, such as disposal of the component's peer, occurs before the request can be granted by the native windowing system. Again, while a return value oftrue
indicates that the request is likely to succeed, developers must never assume that this component is the focus owner until this component receives a FOCUS_GAINED event.
This method cannot be used to set the focus owner to no component at all. UseKeyboardFocusManager.clearGlobalFocusOwner
instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method overrequestFocus
when possible. Code which relies onrequestFocus
may exhibit different focus behavior on different platforms.
Every effort will be made to ensure thatFocusEvent
s generated as a result of this request will have the specified temporary value. However, because specifying an arbitrary temporary state may not be implementable on all native windowing systems, correct behavior for this method can be guaranteed only for lightweight components. This method is not intended for general use, but exists instead as a hook for lightweight component libraries, such as Swing.
Note: Not all focus transfers result from invoking this method. As such, a component may receive focus without this or any of the otherrequestFocus
methods ofComponent
being invoked.
temporary
- true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see theFocus Specificationfalse
if the focus change request is guaranteed to fail;true
if it is likely to succeedrequestFocus()
,FocusEvent
,addFocusListener(java.awt.event.FocusListener)
,isFocusable()
,isDisplayable()
,KeyboardFocusManager.clearGlobalFocusOwner()
public Container getFocusCycleRootAncestor()
Container.isFocusCycleRoot()
public boolean isFocusCycleRoot(Container container)
container
- the Container to be testedtrue
if the specified Container is a focus-cycle- root of this Component;false
otherwiseContainer.isFocusCycleRoot()
public void transferFocus()
requestFocus()
@Deprecatedpublic void nextFocus()
public void transferFocusBackward()
requestFocus()
public void transferFocusUpCycle()
requestFocus()
,Container.isFocusCycleRoot()
,Container.setFocusCycleRoot(boolean)
public boolean hasFocus()
true
if thisComponent
is the focus owner. This method is obsolete, and has been replaced byisFocusOwner()
.true
if thisComponent
is the focus owner;false
otherwisepublic boolean isFocusOwner()
true
if thisComponent
is the focus owner.true
if thisComponent
is the focus owner;false
otherwisepublic void add(PopupMenu popup)
popup
- the popup menu to be added to the component.NullPointerException
- ifpopup
isnull
remove(MenuComponent)
public void remove(MenuComponent popup)
remove
in interface MenuContainer
popup
- the popup menu to be removedadd(PopupMenu)
protected String paramString()
null
.public String toString()
public void list()
System.out
.System.out
public void list(PrintStream out)
out
- a print streamNullPointerException
- ifout
isnull
public void list(PrintStream out, int indent)
out
- a print streamindent
- number of spaces to indentNullPointerException
- ifout
isnull
PrintStream.println(java.lang.Object)
public void list(PrintWriter out)
out
- the print writer to print toNullPointerException
- ifout
isnull
public void list(PrintWriter out, int indent)
out
- the print writer to print toindent
- the number of spaces to indentNullPointerException
- ifout
isnull
PrintStream.println(java.lang.Object)
public void addPropertyChangeListener(PropertyChangeListener listener)
Component
is inheriting a bound property, then no event will be fired in response to a change in the inherited property. Iflistener
isnull
, no exception is thrown and no action is performed.
listener
- the property change listener to be addedremovePropertyChangeListener(java.beans.PropertyChangeListener)
,getPropertyChangeListeners()
,addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
public void removePropertyChangeListener(PropertyChangeListener listener)
If listener is null, no exception is thrown and no action is performed.
listener
- the PropertyChangeListener to be removedaddPropertyChangeListener(java.beans.PropertyChangeListener)
,getPropertyChangeListeners()
,removePropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)
public PropertyChangeListener[] getPropertyChangeListeners()
PropertyChangeListener
s or an empty array if no property change listeners are currently registeredaddPropertyChangeListener(java.beans.PropertyChangeListener)
,removePropertyChangeListener(java.beans.PropertyChangeListener)
,getPropertyChangeListeners(java.lang.String)
,PropertyChangeSupport.getPropertyChangeListeners()
public void addPropertyChangeListener(String propertyName,PropertyChangeListener listener)
Component
is inheriting a bound property, then no event will be fired in response to a change in the inherited property. IfpropertyName
orlistener
isnull
, no exception is thrown and no action is taken.
propertyName
- one of the property names listed abovelistener
- the property change listener to be addedremovePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,getPropertyChangeListeners(java.lang.String)
,addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
public void removePropertyChangeListener(String propertyName,PropertyChangeListener listener)
PropertyChangeListener
from the listener list for a specific property. This method should be used to removePropertyChangeListener
s that were registered for a specific bound property. IfpropertyName
orlistener
isnull
, no exception is thrown and no action is taken.
propertyName
- a valid property namelistener
- the PropertyChangeListener to be removedaddPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,getPropertyChangeListeners(java.lang.String)
,removePropertyChangeListener(java.beans.PropertyChangeListener)
public PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
PropertyChangeListener
s associated with the named property; if no such listeners have been added or ifpropertyName
isnull
, an empty array is returnedaddPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
,getPropertyChangeListeners()
protected void firePropertyChange(String propertyName,Object oldValue,Object newValue)
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new valueprotected void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new valueprotected void firePropertyChange(String propertyName, int oldValue, int newValue)
propertyName
- the property whose value has changedoldValue
- the property's previous valuenewValue
- the property's new valuepublic void firePropertyChange(String propertyName, byte oldValue, byte newValue)
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the property (as a byte)newValue
- the new value of the property (as a byte)firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
public void firePropertyChange(String propertyName, char oldValue, char newValue)
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the property (as a char)newValue
- the new value of the property (as a char)firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
public void firePropertyChange(String propertyName, short oldValue, short newValue)
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the property (as a short)newValue
- the old value of the property (as a short)firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
public void firePropertyChange(String propertyName, long oldValue, long newValue)
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the property (as a long)newValue
- the new value of the property (as a long)firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
public void firePropertyChange(String propertyName, float oldValue, float newValue)
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the property (as a float)newValue
- the new value of the property (as a float)firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
public void firePropertyChange(String propertyName, double oldValue, double newValue)
propertyName
- the programmatic name of the property that was changedoldValue
- the old value of the property (as a double)newValue
- the new value of the property (as a double)firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
public void setComponentOrientation(ComponentOrientation o)
LayoutManager
andComponent
subclasses will use this property to determine how to lay out and draw components. At construction time, a component's orientation is set toComponentOrientation.UNKNOWN
, indicating that it has not been specified explicitly. The UNKNOWN orientation behaves the same asComponentOrientation.LEFT_TO_RIGHT
.
To set the orientation of a single component, use this method. To set the orientation of an entire component hierarchy, useapplyComponentOrientation
.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
ComponentOrientation
,invalidate()
public ComponentOrientation getComponentOrientation()
LayoutManager
andComponent
subclasses that wish to respect orientation should call this method to get the component's orientation before performing layout or drawing.ComponentOrientation
public void applyComponentOrientation(ComponentOrientation orientation)
ComponentOrientation
property of this component and all components contained within it.This method changes layout-related information, and therefore, invalidates the component hierarchy.
orientation
- the new component orientation of this component and the components contained within it.NullPointerException
- iforientation
is null.setComponentOrientation(java.awt.ComponentOrientation)
,getComponentOrientation()
,invalidate()
public AccessibleContext getAccessibleContext()
AccessibleContext
associated with thisComponent
. The method implemented by this base class returns null. Classes that extendComponent
should implement this method to return theAccessibleContext
associated with the subclass.AccessibleContext
of thisComponent