java.lang.Object java.awt.Component
public abstract class Component
A component is an object having a graphical representation that can be displayed on the screen and that can interact with the user. Examples of components are the buttons, checkboxes, and scrollbars of a typical graphical user interface.
The Component class is the abstract superclass of the nonmenu-related Abstract Window Toolkit components. Class Component can also be extended directly to create a lightweight component. A lightweight component is a component that is not associated with a native opaque window.
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 at writeObject 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 cause MyApp 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 about MyApp and the ActionListener 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 java.io.Serializable
{
BigObjectThatShouldNotBeSerializedWithAButton bigOne;
Button aButton = new Button();
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, see Painting in AWT and Swing.
For details on the focus subsystem, see How to Use the Focus Subsystem, a section in The Java Tutorial, and the Focus Specification for more information.
static float BOTTOM_ALIGNMENT
getAlignmentY. static float CENTER_ALIGNMENT
getAlignmentY and getAlignmentX. static float LEFT_ALIGNMENT
getAlignmentX. static float RIGHT_ALIGNMENT
getAlignmentX. static float TOP_ALIGNMENT
getAlignmentY(). Constructor Summary protected Component()
boolean action(Event evt, Object what)
void add(PopupMenu popup)
void addComponentListener(ComponentListener l)
void addFocusListener(FocusListener l)
void addHierarchyBoundsListener(HierarchyBoundsListener l)
void addHierarchyListener(HierarchyListener l)
void addInputMethodListener(InputMethodListener l)
void addKeyListener(KeyListener l)
void addMouseListener(MouseListener l)
void addMouseMotionListener(MouseMotionListener l)
void addMouseWheelListener(MouseWheelListener l)
void addNotify()
Component displayable by connecting it to a native screen resource. void addPropertyChangeListener(PropertyChangeListener listener)
void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
void applyComponentOrientation(ComponentOrientation orientation)
ComponentOrientation property of this component and all components contained within it. boolean areFocusTraversalKeysSet(int id)
Rectangle bounds()
getBounds(). int checkImage(Image image, ImageObserver observer)
int checkImage(Image image, int width, int height, ImageObserver observer)
protected AWTEvent coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent)
boolean contains(int x, int y)
x and y are defined to be relative to the coordinate system of this component. boolean contains(Point p)
Image createImage(ImageProducer producer)
Image createImage(int width, int height)
VolatileImage createVolatileImage(int width, int height)
VolatileImage createVolatileImage(int width, int height, ImageCapabilities caps)
void deliverEvent(Event e)
dispatchEvent(AWTEvent e). void disable()
setEnabled(boolean). protected void disableEvents(long eventsToDisable)
void dispatchEvent(AWTEvent e)
void doLayout()
void enable()
setEnabled(boolean). void enable(boolean b)
setEnabled(boolean). protected void enableEvents(long eventsToEnable)
void enableInputMethods(boolean enable)
protected void firePropertyChange(String propertyName, boolean oldValue, boolean newValue)
void firePropertyChange(String propertyName, byte oldValue, byte newValue)
void firePropertyChange(String propertyName, char oldValue, char newValue)
void firePropertyChange(String propertyName, double oldValue, double newValue)
void firePropertyChange(String propertyName, float oldValue, float newValue)
protected void firePropertyChange(String propertyName, int oldValue, int newValue)
void firePropertyChange(String propertyName, long oldValue, long newValue)
protected void firePropertyChange(String propertyName, Object oldValue, Object newValue)
void firePropertyChange(String propertyName, short oldValue, short newValue)
AccessibleContext getAccessibleContext()
AccessibleContext associated with this Component. float getAlignmentX()
float getAlignmentY()
Color getBackground()
Rectangle getBounds()
Rectangle object. Rectangle getBounds(Rectangle rv)
ColorModel getColorModel()
ColorModel used to display the component on the output device. Component getComponentAt(int x, int y)
Component getComponentAt(Point p)
ComponentListener[] getComponentListeners()
ComponentOrientation getComponentOrientation()
Cursor getCursor()
DropTarget getDropTarget()
DropTarget associated with this Component. Container getFocusCycleRootAncestor()
FocusListener[] getFocusListeners()
Set<AWTKeyStroke> getFocusTraversalKeys(int id)
boolean getFocusTraversalKeysEnabled()
Font getFont()
FontMetrics getFontMetrics(Font font)
Color getForeground()
Graphics getGraphics()
GraphicsConfiguration getGraphicsConfiguration()
GraphicsConfiguration associated with this Component. int getHeight()
HierarchyBoundsListener[] getHierarchyBoundsListeners()
HierarchyListener[] getHierarchyListeners()
boolean getIgnoreRepaint()
InputContext getInputContext()
InputMethodListener[] getInputMethodListeners()
InputMethodRequests getInputMethodRequests()
KeyListener[] getKeyListeners()
<T extends EventListener>
T[] getListeners(Class<T> listenerType)
FooListeners upon this Component. Locale getLocale()
Point getLocation()
Point getLocation(Point rv)
Point getLocationOnScreen()
Dimension getMaximumSize()
Dimension getMinimumSize()
MouseListener[] getMouseListeners()
MouseMotionListener[] getMouseMotionListeners()
Point getMousePosition()
Component's coordinate space if the Component is directly under the mouse pointer, otherwise returns null. MouseWheelListener[] getMouseWheelListeners()
String getName()
Container getParent()
java.awt.peer.ComponentPeer getPeer()
boolean isDisplayable(). Dimension getPreferredSize()
PropertyChangeListener[] getPropertyChangeListeners()
PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
Dimension getSize()
Dimension object. Dimension getSize(Dimension rv)
Toolkit getToolkit()
Object getTreeLock()
int getWidth()
int getX()
int getY()
boolean gotFocus(Event evt, Object what)
boolean handleEvent(Event evt)
boolean hasFocus()
true if this Component is the focus owner. void hide()
setVisible(boolean). boolean imageUpdate(Image img, int infoflags, int x, int y, int w, int h)
boolean inside(int x, int y)
void invalidate()
boolean isBackgroundSet()
boolean isCursorSet()
boolean isDisplayable()
boolean isDoubleBuffered()
boolean isEnabled()
boolean isFocusable()
boolean isFocusCycleRoot(Container container)
boolean isFocusOwner()
true if this Component is the focus owner. boolean isFocusTraversable()
isFocusable(). boolean isFontSet()
boolean isForegroundSet()
boolean isLightweight()
boolean isMaximumSizeSet()
null value otherwise returns false. boolean isMinimumSizeSet()
setMinimumSize has been invoked with a non-null value. boolean isOpaque()
boolean isPreferredSizeSet()
null value otherwise returns false. boolean isShowing()
boolean isValid()
boolean isVisible()
boolean keyDown(Event evt, int key)
boolean keyUp(Event evt, int key)
void layout()
doLayout(). void list()
System.out. void list(PrintStream out)
void list(PrintStream out, int indent)
void list(PrintWriter out)
void list(PrintWriter out, int indent)
Component locate(int x, int y)
Point location()
getLocation(). boolean lostFocus(Event evt, Object what)
Dimension minimumSize()
getMinimumSize(). boolean mouseDown(Event evt, int x, int y)
boolean mouseDrag(Event evt, int x, int y)
boolean mouseEnter(Event evt, int x, int y)
boolean mouseExit(Event evt, int x, int y)
boolean mouseMove(Event evt, int x, int y)
boolean mouseUp(Event evt, int x, int y)
void move(int x, int y)
setLocation(int, int). void nextFocus()
void paint(Graphics g)
void paintAll(Graphics g)
protected String paramString()
boolean postEvent(Event e)
Dimension preferredSize()
getPreferredSize(). boolean prepareImage(Image image, ImageObserver observer)
boolean prepareImage(Image image, int width, int height, ImageObserver observer)
void print(Graphics g)
void printAll(Graphics g)
protected void processComponentEvent(ComponentEvent e)
ComponentListener objects. protected void processEvent(AWTEvent e)
protected void processFocusEvent(FocusEvent e)
FocusListener objects. protected void processHierarchyBoundsEvent(HierarchyEvent e)
HierarchyBoundsListener objects. protected void processHierarchyEvent(HierarchyEvent e)
HierarchyListener objects. protected void processInputMethodEvent(InputMethodEvent e)
InputMethodListener objects. protected void processKeyEvent(KeyEvent e)
KeyListener objects. protected void processMouseEvent(MouseEvent e)
MouseListener objects. protected void processMouseMotionEvent(MouseEvent e)
MouseMotionListener objects. protected void processMouseWheelEvent(MouseWheelEvent e)
MouseWheelListener objects. void remove(MenuComponent popup)
void removeComponentListener(ComponentListener l)
void removeFocusListener(FocusListener l)
void removeHierarchyBoundsListener(HierarchyBoundsListener l)
void removeHierarchyListener(HierarchyListener l)
void removeInputMethodListener(InputMethodListener l)
void removeKeyListener(KeyListener l)
void removeMouseListener(MouseListener l)
void removeMouseMotionListener(MouseMotionListener l)
void removeMouseWheelListener(MouseWheelListener l)
void removeNotify()
Component undisplayable by destroying it native screen resource. void removePropertyChangeListener(PropertyChangeListener listener)
void removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
PropertyChangeListener from the listener list for a specific property. void repaint()
void repaint(int x, int y, int width, int height)
void repaint(long tm)
void repaint(long tm, int x, int y, int width, int height)
tm milliseconds. void requestFocus()
protected boolean requestFocus(boolean temporary)
Component get the input focus, and that this Component's top-level ancestor become the focused Window. boolean requestFocusInWindow()
protected boolean requestFocusInWindow(boolean temporary)
Component get the input focus, if this Component's top-level ancestor is already the focused Window. void reshape(int x, int y, int width, int height)
setBounds(int, int, int, int). void resize(Dimension d)
setSize(Dimension). void resize(int width, int height)
setSize(int, int). void setBackground(Color c)
void setBounds(int x, int y, int width, int height)
void setBounds(Rectangle r)
r. void setComponentOrientation(ComponentOrientation o)
void setCursor(Cursor cursor)
void setDropTarget(DropTarget dt)
DropTarget with this component. void setEnabled(boolean b)
b. void setFocusable(boolean focusable)
void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
void setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)
void setFont(Font f)
void setForeground(Color c)
void setIgnoreRepaint(boolean ignoreRepaint)
void setLocale(Locale l)
void setLocation(int x, int y)
void setLocation(Point p)
void setMaximumSize(Dimension maximumSize)
void setMinimumSize(Dimension minimumSize)
void setName(String name)
void setPreferredSize(Dimension preferredSize)
void setSize(Dimension d)
d.width and height d.height. void setSize(int width, int height)
width and height height. void setVisible(boolean b)
b. void show()
setVisible(boolean). void show(boolean b)
setVisible(boolean). Dimension size()
getSize(). String toString()
void transferFocus()
void transferFocusBackward()
void transferFocusUpCycle()
void update(Graphics g)
void validate()
public static final float TOP_ALIGNMENT
getAlignmentY(). Specifies an alignment to the top of the component.
getAlignmentY(), Constant Field Values
public static final float CENTER_ALIGNMENT
getAlignmentY and getAlignmentX. Specifies an alignment to the center of the component
getAlignmentX(), getAlignmentY(), Constant Field Values
public static final float BOTTOM_ALIGNMENT
getAlignmentY. Specifies an alignment to the bottom of the component.
getAlignmentY(), Constant Field Values
public static final float LEFT_ALIGNMENT
getAlignmentX. Specifies an alignment to the left side of the component.
getAlignmentX(), Constant Field Values
public static final float RIGHT_ALIGNMENT
getAlignmentX. Specifies an alignment to the right side of the component.
getAlignmentX(), Constant Field Values
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 a Frame object).
public String getName()
setName(java.lang.String)
public void setName(String name)
name - the string that is to be this component's name
getName()
public Container getParent()
@Deprecated public java.awt.peer.ComponentPeer getPeer()
boolean isDisplayable().
public void setDropTarget(DropTarget dt)
DropTarget with this component. The Component will receive drops only if it is enabled.
dt - The DropTarget
isEnabled()
public DropTarget getDropTarget()
DropTarget associated with this Component.
public GraphicsConfiguration getGraphicsConfiguration()
GraphicsConfiguration associated with this Component. If the Component has not been assigned a specific GraphicsConfiguration, the GraphicsConfiguration of the Component object's top-level container is returned. If the Component has been created, but not yet added to a Container, this method returns null.
GraphicsConfiguration used by this Component or null
public final Object getTreeLock()
public Toolkit getToolkit()
public boolean isValid()
true if the component is valid, false otherwise
validate(), 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 otherwise
Container.add(Component), Window.pack(), Window.show(), Container.remove(Component), Window.dispose()
public boolean isVisible()
Frame objects.
true if the component is visible, false otherwise
setVisible(boolean)
public Point getMousePosition()
throws HeadlessException
Component's coordinate space if the Component is directly under the mouse pointer, otherwise returns null. If the Component is not showing on the screen, this method returns null even if the mouse pointer is above the area where the Component would be displayed. If the Component is partially or fully obscured by other Components or native windows, this method returns a non-null value only if the mouse pointer is located above the unobscured part of the Component.
For Containers it returns a non-null value if the mouse is above the Container itself or above any of its descendants. Use Container.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 specific Component is under the mouse pointer. If the return value of this method is null, mouse pointer is not directly above the Component.
Component, or null
HeadlessException - if GraphicsEnvironment.isHeadless() returns true
isShowing(), Container.getMousePosition(boolean)
public boolean isShowing()
true if the component is showing, false otherwise
setVisible(boolean)
public boolean isEnabled()
setEnabled method.
true if the component is enabled, false otherwise
setEnabled(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.
b - If true, this component is enabled; otherwise this component is disabled
isEnabled(), isLightweight()
@Deprecated public void enable()
setEnabled(boolean).
@Deprecated public void enable(boolean b)
setEnabled(boolean).
@Deprecated public void disable()
setEnabled(boolean).
public boolean isDoubleBuffered()
public void enableInputMethods(boolean enable)
enable - true to enable, false to disable
processKeyEvent(java.awt.event.KeyEvent)
public void setVisible(boolean b)
b.
b - if true, shows this component; otherwise, hides this component
isVisible()
@Deprecated public void show()
setVisible(boolean).
@Deprecated public void show(boolean b)
setVisible(boolean).
@Deprecated public 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 is null then this component will inherit the foreground color of its parent
getForeground()
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 is null, then this component will inherit the background color of its parent
getBackground()
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)
f - the font to become this component's font; if this parameter is null then this component will inherit the font of its parent
getFont()
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 the Component 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 parent
setLocale(java.util.Locale)
public void setLocale(Locale l)
l - the locale to become this component's locale
getLocale()
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 of setLocation() in rapid succession). For this reason, the recommended method of obtaining a component's position is within java.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 parent
setLocation(int, int), getLocationOnScreen()
public Point getLocationOnScreen()
Point representing the top-left corner of the component's bounds in the coordinate space of the screen
IllegalComponentStateExceptionsetLocation(int, int), getLocation()
@Deprecated public Point location()
getLocation().
public void setLocation(int x,
int y)
x and y parameters in the coordinate space of this component's parent.
x - the x-coordinate of the new location's top-left corner in the parent's coordinate space
y - the y-coordinate of the new location's top-left corner in the parent's coordinate space
getLocation(), setBounds(int, int, int, int)
@Deprecated
public void move(int x,
int y)
setLocation(int, int).
public void setLocation(Point p)
p. Point p is given in the parent's coordinate space.
p - the point defining the top-left corner of the new location, given in the coordinate space of this component's parent
getLocation(), setBounds(int, int, int, int)
public Dimension getSize()
Dimension object. The height field of the Dimension object contains this component's height, and the width field of the Dimension object contains this component's width.
Dimension object that indicates the size of this component
setSize(int, int)
@Deprecated public Dimension size()
getSize().
public void setSize(int width,
int height)
width and height height.
width - the new width of this component in pixels
height - the new height of this component in pixels
getSize(), setBounds(int, int, int, int)
@Deprecated
public void resize(int width,
int height)
setSize(int, int).
public void setSize(Dimension d)
d.width and height d.height.
d - the dimension specifying the new size of this component
setSize(int, int), setBounds(int, int, int, int)
@Deprecated public 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()
@Deprecated public Rectangle bounds()
getBounds().
public void setBounds(int x,
int y,
int width,
int height)
x and y, and the new size is specified by width and height.
x - the new x-coordinate of this component
y - the new y-coordinate of this component
width - the new width of this component
height - the new height of this component
getBounds(), setLocation(int, int), setLocation(Point), setSize(int, int), setSize(Dimension)
@Deprecated
public 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 by r.x and r.y, and its new size is specified by r.width and r.height
r - the new bounding rectangle for this component
getBounds(), setLocation(int, int), setLocation(Point), setSize(int, int), setSize(Dimension)
public int getX()
component.getBounds().x, or component.getLocation().x because it doesn't cause any heap allocations.
public int getY()
component.getBounds().y, or component.getLocation().y because it doesn't cause any heap allocations.
public int getWidth()
component.getBounds().width, or component.getSize().width because it doesn't cause any heap allocations.
public int getHeight()
component.getBounds().heightcomponent.getSize().height because it doesn't cause any heap allocations.
public Rectangle getBounds(Rectangle rv)
null a new Rectangle is allocated. This version of getBounds is useful if the caller wants to avoid allocating a new Rectangle object on the heap.
rv - the return value, modified to the components bounds
public Dimension getSize(Dimension rv)
null a new Dimension object is allocated. This version of getSize is useful if the caller wants to avoid allocating a new Dimension object on the heap.
rv - the return value, modified to the components size
public Point getLocation(Point rv)
null a new Point is allocated. This version of getLocation is useful if the caller wants to avoid allocating a new Point object on the heap.
rv - the return value, modified to the components location
public 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. Only lightweight components can be transparent.
Subclasses that guarantee to always completely paint their contents should override this method and return true. All of the "heavyweight" AWT components are opaque.
isLightweight()
public boolean isLightweight()
Component and Container, other than the ones defined in this package like Button or Scrollbar, are lightweight. All of the Swing components are lightweights.
This method will always return false 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 to null restores the default behavior.
preferredSize - The new preferred size, or null
getPreferredSize(), isPreferredSizeSet()
public boolean isPreferredSizeSet()
null value otherwise returns false.
setPreferredSize has been invoked with a non-null value.
public Dimension getPreferredSize()
getMinimumSize(), LayoutManager
@Deprecated public Dimension preferredSize()
getPreferredSize().
public void setMinimumSize(Dimension minimumSize)
getMinimumSize will always return this value. Setting the minimum size to null restores the default behavior.
minimumSize - the new minimum size of this component
getMinimumSize(), 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
@Deprecated public Dimension minimumSize()
getMinimumSize().
public void setMaximumSize(Dimension maximumSize)
getMaximumSize will always return this value. Setting the maximum size to null restores the default behavior.
maximumSize - a Dimension containing the desired maximum allowable size
getMaximumSize(), isMaximumSizeSet()
public boolean isMaximumSizeSet()
null value otherwise returns false.
maximumSize is non-null, false otherwise
public Dimension getMaximumSize()
getMinimumSize(), getPreferredSize(), LayoutManager
public float getAlignmentX()
public float getAlignmentY()
public void doLayout()
validate(), LayoutManager
@Deprecated public void layout()
doLayout().
public void validate()
Container.
invalidate(), doLayout(), LayoutManager, Container.validate()
public void invalidate()
validate(), doLayout(), LayoutManager
public Graphics getGraphics()
null if this component is currently not displayable.
null if it has none
paint(java.awt.Graphics)
public FontMetrics getFontMetrics(Font font)
font - the font for which font metrics is to be obtained
font
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 a Container causes that cursor to be displayed within all of the container's subcomponents, except for those that have a non-null cursor.
cursor - One of the constants defined by the Cursor class; if this parameter is null then this component will inherit the cursor of its parent
isEnabled(), 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 the Graphics parameter is set to the area which needs to be painted. Subclasses of Component that override this method need not call super.paint(g).
For performance reasons, Components 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, see Painting in AWT and Swing.
g - the graphics context to use for painting
update(java.awt.Graphics)
public void update(Graphics g)
If this component is not a lightweight component, the AWT calls the update method in response to a call to repaint. You can assume that the background is not cleared.
The update method of Component calls this component's paint method to redraw this component. This method is commonly overridden by subclasses which need to do additional work in response to a call to repaint. Subclasses of Component that override this method should either call super.update(g), or call paint(g) directly from their update 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, see Painting in AWT and Swing.
g - the specified context to use for updating
paint(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 painting
paint(java.awt.Graphics)
public void repaint()
If this component is a lightweight component, this method causes a call to this component's paint method as soon as possible. Otherwise, this method causes a call to this component's update 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, see Painting in AWT and Swing.
update(Graphics)
public void repaint(long tm)
paint within tm 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, see Painting in AWT and Swing.
tm - maximum time in milliseconds before update
paint(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's paint method as soon as possible. Otherwise, this method causes a call to this component's update 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, see Painting in AWT and Swing.
x - the x coordinate
y - the y coordinate
width - the width
height - the height
update(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's paint method. Otherwise, this method causes a call to this component's update 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, see Painting in AWT and Swing.
tm - maximum time in milliseconds before update
x - the x coordinate
y - the y coordinate
width - the width
height - the height
update(Graphics)
public void print(Graphics g)
The default implementation of this method calls the paint 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 printing
paint(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 printing
print(Graphics)
public boolean imageUpdate(Image img,
int infoflags,
int x,
int y,
int w,
int h)
imageUpdate method of an ImageObserver is called when more information about an image which had been previously requested using an asynchronous routine such as the drawImage method of Graphics becomes available. See the definition of imageUpdate for more information on this method and its arguments.
The imageUpdate method of Component incrementally draws an image on the component as more of the bits of the image are available.
If the system property awt.image.incrementaldraw is missing or has the value true, 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 property awt.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 the x, y, width, and height arguments depends on the value of the infoflags argument.
imageUpdate in interface ImageObserver
img - the image being observed
infoflags - see imageUpdate for more information
x - the x coordinate
y - the y coordinate
w - the width
h - the height
false 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 producer
public Image createImage(int width,
int height)
width - the specified width
height - the specified height
null if the component is not displayable. This will always happen if GraphicsEnvironment.isHeadless() returns true.
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 if GraphicsEnvironment.isHeadless() returns true.
VolatileImage, isDisplayable(), GraphicsEnvironment.isHeadless()
public VolatileImage createVolatileImage(int width,
int height,
ImageCapabilities caps)
throws AWTException
VolatileImage interface.
width - the specified width.
height - the specified height.
caps - the image capabilities
AWTException - if an image with the specified capabilities cannot be created
VolatileImage
public boolean prepareImage(Image image,
ImageObserver observer)
image - the Image for which to prepare a screen representation
observer - the ImageObserver object to be notified as the image is being prepared
true if the image has already been fully prepared; false otherwise
public 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 of Image for which to prepare a screen representation
width - the width of the desired screen representation
height - the height of the desired screen representation
observer - the ImageObserver object to be notified as the image is being prepared
true if the image has already been fully prepared; false otherwise
ImageObserver
public int checkImage(Image image,
ImageObserver observer)
This method does not cause the image to begin loading. An application must use the prepareImage method to force the loading of an image.
Information on the flags returned by this method can be found with the discussion of the ImageObserver interface.
image - the Image object whose status is being checked
observer - the ImageObserver object to be notified as the image is being prepared
ImageObserver flags indicating what information about the image is currently available
prepareImage(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 the prepareImage method to force the loading of an image.
The checkImage method of Component calls its peer's checkImage method to calculate the flags. If this component does not yet have a peer, the component's toolkit's checkImage method is called instead.
Information on the flags returned by this method can be found with the discussion of the ImageObserver interface.
image - the Image object whose status is being checked
width - the width of the scaled version whose status is to be checked
height - the height of the scaled version whose status is to be checked
observer - the ImageObserver object to be notified as the image is being prepared
ImageObserver flags indicating what information about the image is currently available
prepareImage(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.
getIgnoreRepaint(), Canvas.createBufferStrategy(int), Window.createBufferStrategy(int), BufferStrategy, GraphicsDevice.setFullScreenWindow(java.awt.Window)
public boolean getIgnoreRepaint()
setIgnoreRepaint(boolean)
public boolean contains(int x,
int y)
x and y are defined to be relative to the coordinate system of this component.
x - the x coordinate of the point
y - the y coordinate of the point
getComponentAt(int, int)
@Deprecated
public boolean inside(int x,
int y)
public boolean contains(Point p)
p - the point
getComponentAt(Point)
public Component getComponentAt(int x,
int y)
The locate method of Component simply returns the component itself if the (x, y) coordinate location is inside its bounding box, and null otherwise.
x - the x coordinate
y - the y coordinate
null if the location is outside this component
contains(int, int)
@Deprecated
public Component locate(int x,
int y)
public Component getComponentAt(Point p)
p - the point
contains(int, int)
@Deprecated public 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 the Component.
e - the event
@Deprecated public boolean postEvent(Event e)
postEvent in interface MenuContainer
public void addComponentListener(ComponentListener l)
l is null, no exception is thrown and no action is performed.
l - the component listener
ComponentEvent, ComponentListener, removeComponentListener(java.awt.event.ComponentListener), getComponentListeners()
public void removeComponentListener(ComponentListener l)
l is null, no exception is thrown and no action is performed.
l - the component listener
ComponentEvent, ComponentListener, addComponentListener(java.awt.event.ComponentListener), getComponentListeners()
public ComponentListener[] getComponentListeners()
ComponentListeners or an empty array if no component listeners are currently registered
addComponentListener(java.awt.event.ComponentListener), removeComponentListener(java.awt.event.ComponentListener)
public void addFocusListener(FocusListener l)
l is null, no exception is thrown and no action is performed.
l - the focus listener
FocusEvent, FocusListener, removeFocusListener(java.awt.event.FocusListener), getFocusListeners()
public void removeFocusListener(FocusListener l)
l is null, no exception is thrown and no action is performed.
l - the focus listener
FocusEvent, FocusListener, addFocusListener(java.awt.event.FocusListener), getFocusListeners()
public FocusListener[] getFocusListeners()
FocusListeners or an empty array if no component listeners are currently registered
addFocusListener(java.awt.event.FocusListener), removeFocusListener(java.awt.event.FocusListener)
public void addHierarchyListener(HierarchyListener l)
l is null, no exception is thrown and no action is performed.
l - the hierarchy listener
HierarchyEvent, HierarchyListener, removeHierarchyListener(java.awt.event.HierarchyListener), getHierarchyListeners()
public void removeHierarchyListener(HierarchyListener l)
l is null, no exception is thrown and no action is performed.
l - the hierarchy listener
HierarchyEvent, HierarchyListener, addHierarchyListener(java.awt.event.HierarchyListener), getHierarchyListeners()
public HierarchyListener[] getHierarchyListeners()
HierarchyListeners or an empty array if no hierarchy listeners are currently registered
addHierarchyListener(java.awt.event.HierarchyListener), removeHierarchyListener(java.awt.event.HierarchyListener)
public void addHierarchyBoundsListener(HierarchyBoundsListener l)
l is null, no exception is thrown and no action is performed.
l - the hierarchy bounds listener
HierarchyEvent, HierarchyBoundsListener, removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener), getHierarchyBoundsListeners()
public void removeHierarchyBoundsListener(HierarchyBoundsListener l)
l is null, no exception is thrown and no action is performed.
l - the hierarchy bounds listener
HierarchyEvent, HierarchyBoundsListener, addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener), getHierarchyBoundsListeners()
public HierarchyBoundsListener[] getHierarchyBoundsListeners()
HierarchyBoundsListeners or an empty array if no hierarchy bounds listeners are currently registered
addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener), removeHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener)
public void addKeyListener(KeyListener l)
l - the key listener.
KeyEvent, KeyListener, removeKeyListener(java.awt.event.KeyListener), getKeyListeners()
public void removeKeyListener(KeyListener l)
l is null, no exception is thrown and no action is performed.
l - the key listener
KeyEvent, KeyListener, addKeyListener(java.awt.event.KeyListener), getKeyListeners()
public KeyListener[] getKeyListeners()
KeyListeners or an empty array if no key listeners are currently registered
addKeyListener(java.awt.event.KeyListener), removeKeyListener(java.awt.event.KeyListener)
public void addMouseListener(MouseListener l)
l is null, no exception is thrown and no action is performed.
l - the mouse listener
MouseEvent, MouseListener, removeMouseListener(java.awt.event.MouseListener), getMouseListeners()
public void removeMouseListener(MouseListener l)
l is null, no exception is thrown and no action is performed.
l - the mouse listener
MouseEvent, MouseListener, addMouseListener(java.awt.event.MouseListener), getMouseListeners()
public MouseListener[] getMouseListeners()
MouseListeners or an empty array if no mouse listeners are currently registered
addMouseListener(java.awt.event.MouseListener), removeMouseListener(java.awt.event.MouseListener)
public void addMouseMotionListener(MouseMotionListener l)
l is null, no exception is thrown and no action is performed.
l - the mouse motion listener
MouseEvent, MouseMotionListener, removeMouseMotionListener(java.awt.event.MouseMotionListener), getMouseMotionListeners()
public void removeMouseMotionListener(MouseMotionListener l)
l is null, no exception is thrown and no action is performed.
l - the mouse motion listener
MouseEvent, MouseMotionListener, addMouseMotionListener(java.awt.event.MouseMotionListener), getMouseMotionListeners()
public MouseMotionListener[] getMouseMotionListeners()
MouseMotionListeners or an empty array if no mouse motion listeners are currently registered
addMouseMotionListener(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 for MouseWheelEvent.
If l is null, no exception is thrown and no action is performed.
l - the mouse wheel listener
MouseWheelEvent, MouseWheelListener, removeMouseWheelListener(java.awt.event.MouseWheelListener), getMouseWheelListeners()
public void removeMouseWheelListener(MouseWheelListener l)
l - the mouse wheel listener.
MouseWheelEvent, MouseWheelListener, addMouseWheelListener(java.awt.event.MouseWheelListener), getMouseWheelListeners()
public MouseWheelListener[] getMouseWheelListeners()
MouseWheelListeners or an empty array if no mouse wheel listeners are currently registered
addMouseWheelListener(java.awt.event.MouseWheelListener), removeMouseWheelListener(java.awt.event.MouseWheelListener)
public void addInputMethodListener(InputMethodListener l)
getInputMethodRequests to return an InputMethodRequests instance. If listener l is null, no exception is thrown and no action is performed.
l - the input method listener
InputMethodEvent, InputMethodListener, removeInputMethodListener(java.awt.event.InputMethodListener), getInputMethodListeners(), getInputMethodRequests()
public void removeInputMethodListener(InputMethodListener l)
l is null, no exception is thrown and no action is performed.
l - the input method listener
InputMethodEvent, InputMethodListener, addInputMethodListener(java.awt.event.InputMethodListener), getInputMethodListeners()
public InputMethodListener[] getInputMethodListeners()
InputMethodListeners or an empty array if no input method listeners are currently registered
addInputMethodListener(java.awt.event.InputMethodListener), removeInputMethodListener(java.awt.event.InputMethodListener)
public <T extends EventListener> T[] getListeners(Class<T> listenerType)
FooListeners upon this Component. FooListeners are registered using the addFooListener method.
You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a Component 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 from java.util.EventListener
FooListeners on this component, or an empty array if no such listeners have been added
ClassCastException - if listenerType doesn't specify a class or interface that implements java.util.EventListener
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 default
addInputMethodListener(java.awt.event.InputMethodListener)
public InputContext getInputContext()
null if no context can be determined
protected 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 of Component which desire to have the specified event types delivered to processEvent regardless of whether or not a listener is registered.
eventsToEnable - the event mask defining the event types
processEvent(java.awt.AWTEvent), disableEvents(long), AWTEvent
protected final void disableEvents(long eventsToDisable)
eventsToDisable - the event mask defining the event types
enableEvents(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), or null 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 unless null is returned.
This implementation of coalesceEvents 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 complex RepaintArea in the peer. The new AWTEvent is always returned.
existingEvent - the event already on the EventQueue
newEvent - the event being posted to the EventQueue
null indicating that no coalescing was done
protected void processEvent(AWTEvent e)
process<event type>Event method for the given class of event.
Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the event
processComponentEvent(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 via addComponentListener.enableEvents.Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the component event
ComponentEvent, 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 via addFocusListener.enableEvents.If focus events are enabled for a Component, the current KeyboardFocusManager determines whether or not a focus event should be dispatched to registered FocusListener objects. If the events are to be dispatched, the KeyboardFocusManager calls the Component's dispatchEvent method, which results in a call to the Component's processFocusEvent method.
If focus events are enabled for a Component, calling the Component's dispatchEvent method with a FocusEvent as the argument will result in a call to the Component's processFocusEvent method regardless of the current KeyboardFocusManager.
Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the focus event
FocusEvent, 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 via addKeyListener.enableEvents.If key events are enabled for a Component, the current KeyboardFocusManager determines whether or not a key event should be dispatched to registered KeyListener objects. The DefaultKeyboardFocusManager will not dispatch key events to a Component that is not the focus owner or is not showing.
As of J2SE 1.4, KeyEvents are redirected to the focus owner. Please see the Focus Specification for further information.
Calling a Component's dispatchEvent method with a KeyEvent as the argument will result in a call to the Component's processKeyEvent method regardless of the current KeyboardFocusManager as long as the component is showing, focused, and enabled, and key events are enabled on it.
If the event parameter is null the behavior is unspecified and may result in an exception.
e - the key event
KeyEvent, 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 via addMouseListener.enableEvents.Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the mouse event
MouseEvent, 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 via addMouseMotionListener.enableEvents.Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the mouse motion event
MouseEvent, 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 via addMouseWheelListener.enableEvents.For information on how mouse wheel events are dispatched, see the class description for MouseWheelEvent.
Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the mouse wheel event
MouseWheelEvent, 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 via addInputMethodListener.enableEvents.Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the input method event
InputMethodEvent, 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 via addHierarchyListener.enableEvents.Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the hierarchy event
HierarchyEvent, 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 via addHierarchyBoundsListener.enableEvents.Note that if the event parameter is null the behavior is unspecified and may result in an exception.
e - the hierarchy event
HierarchyEvent, HierarchyBoundsListener, addHierarchyBoundsListener(java.awt.event.HierarchyBoundsListener), enableEvents(long)
@Deprecated public boolean handleEvent(Event evt)
@Deprecated
public boolean mouseDown(Event evt,
int x,
int y)
@Deprecated
public boolean mouseDrag(Event evt,
int x,
int y)
@Deprecated
public boolean mouseUp(Event evt,
int x,
int y)
@Deprecated
public boolean mouseMove(Event evt,
int x,
int y)
@Deprecated
public boolean mouseEnter(Event evt,
int x,
int y)
@Deprecated
public boolean mouseExit(Event evt,
int x,
int y)
@Deprecated
public boolean keyDown(Event evt,
int key)
@Deprecated
public boolean keyUp(Event evt,
int key)
@Deprecated
public 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.
isDisplayable(), removeNotify()
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 call super.removeNotify as the first line of the overriding method.
isDisplayable(), addNotify()
@Deprecated
public boolean gotFocus(Event evt,
Object what)
@Deprecated
public boolean lostFocus(Event evt,
Object what)
@Deprecated public boolean isFocusTraversable()
isFocusable().
Component can become the focus owner.
true if this Component is focusable; false otherwise
setFocusable(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 focusable
isFocusable()
public void setFocusTraversalKeys(int id,
Set<? extends AWTKeyStroke> 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 To disable a traversal key, use an empty Set; Collections.EMPTY_SET is recommended.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.
id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
keystrokes - the Set of AWTKeyStroke for the specified operation
IllegalArgumentException - 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 Object in keystrokes is not an AWTKeyStroke, or if any keystroke represents a KEY_TYPED event, or if any keystroke already maps to another focus traversal operation for this Component
getFocusTraversalKeys(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_KEYS
IllegalArgumentException - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, or KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS
setFocusTraversalKeys(int, java.util.Set), 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_KEYS
true 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_KEYS
public void setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled)
focusTraversalKeysEnabled - whether focus traversal keys are enabled for this Component
getFocusTraversalKeysEnabled(), setFocusTraversalKeys(int, java.util.Set), getFocusTraversalKeys(int)
public boolean getFocusTraversalKeysEnabled()
setFocusTraversalKeysEnabled(boolean), setFocusTraversalKeys(int, java.util.Set), getFocusTraversalKeys(int)
public void requestFocus()
This method cannot be used to set the focus owner to no Component at all. Use KeyboardFocusManager.clearGlobalFocusOwner() instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow when possible.
requestFocusInWindow(), FocusEvent, addFocusListener(java.awt.event.FocusListener), isFocusable(), isDisplayable(), KeyboardFocusManager.clearGlobalFocusOwner()
protected boolean requestFocus(boolean temporary)
Component get the input focus, and that this Component's top-level ancestor become the focused Window. This component must be displayable, visible, and focusable 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. If false is returned, the request is guaranteed to fail. If true is returned, the request will succeed unless 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 of true 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. Use KeyboardFocusManager.clearGlobalFocusOwner instead.
Because the focus behavior of this method is platform-dependent, developers are strongly encouraged to use requestFocusInWindow when possible.
Every effort will be made to ensure that FocusEvents 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.
temporary - true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see the Focus Specification
false if the focus change request is guaranteed to fail; true if it is likely to succeed
FocusEvent, addFocusListener(java.awt.event.FocusListener), isFocusable(), isDisplayable(), KeyboardFocusManager.clearGlobalFocusOwner()
public boolean requestFocusInWindow()
This method returns a boolean value. If false is returned, the request is guaranteed to fail. If true is returned, the request will succeed unless 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 of true 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. Use KeyboardFocusManager.clearGlobalFocusOwner() instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method over requestFocus when possible. Code which relies on requestFocus may exhibit different focus behavior on different platforms.
false if the focus change request is guaranteed to fail; true if it is likely to succeed
requestFocus(), FocusEvent, addFocusListener(java.awt.event.FocusListener), isFocusable(), isDisplayable(), KeyboardFocusManager.clearGlobalFocusOwner()
protected boolean requestFocusInWindow(boolean temporary)
Component get the input focus, if this Component's top-level ancestor is already the focused Window. This component must be displayable, visible, and focusable 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. If false is returned, the request is guaranteed to fail. If true is returned, the request will succeed unless 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 of true 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. Use KeyboardFocusManager.clearGlobalFocusOwner instead.
The focus behavior of this method can be implemented uniformly across platforms, and thus developers are strongly encouraged to use this method over requestFocus when possible. Code which relies on requestFocus may exhibit different focus behavior on different platforms.
Every effort will be made to ensure that FocusEvents 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.
temporary - true if the focus change is temporary, such as when the window loses the focus; for more information on temporary focus changes see the Focus Specification
false if the focus change request is guaranteed to fail; true if it is likely to succeed
requestFocus(), FocusEvent, addFocusListener(java.awt.event.FocusListener), isFocusable(), isDisplayable(), KeyboardFocusManager.clearGlobalFocusOwner()
public void transferFocus()
requestFocus()
public Container getFocusCycleRootAncestor()
Container.isFocusCycleRoot()
public boolean isFocusCycleRoot(Container container)
container - the Container to be tested
true if the specified Container is a focus-cycle- root of this Component; false otherwise
Container.isFocusCycleRoot()
@Deprecated public void nextFocus()
public void transferFocusBackward()
requestFocus()
public void transferFocusUpCycle()
requestFocus(), Container.isFocusCycleRoot(), Container.setFocusCycleRoot(boolean)
public boolean hasFocus()
true if this Component is the focus owner. This method is obsolete, and has been replaced by isFocusOwner().
true if this Component is the focus owner; false otherwise
public boolean isFocusOwner()
true if this Component is the focus owner.
true if this Component is the focus owner; false otherwise
public void add(PopupMenu popup)
popup - the popup menu to be added to the component.
remove(MenuComponent)
public void remove(MenuComponent popup)
remove in interface MenuContainer
popup - the popup menu to be removed
add(PopupMenu)
protected String paramString()
null.
public String toString()
toString in class Object
public void list()
System.out.
System.out
public void list(PrintStream out)
out - a print stream
public void list(PrintStream out,
int indent)
out - a print stream
indent - number of spaces to indent
PrintStream.println(java.lang.Object)
public void list(PrintWriter out)
out - the print writer to print to
public void list(PrintWriter out,
int indent)
out - the print writer to print to
indent - the number of spaces to indent
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.
If listener is null, no exception is thrown and no action is performed.
listener - the property change listener to be added
removePropertyChangeListener(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 removed
addPropertyChangeListener(java.beans.PropertyChangeListener), getPropertyChangeListeners(), removePropertyChangeListener(java.lang.String,java.beans.PropertyChangeListener)
public PropertyChangeListener[] getPropertyChangeListeners()
PropertyChangeListeners or an empty array if no property change listeners are currently registered
addPropertyChangeListener(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.
If propertyName or listener is null, no exception is thrown and no action is taken.
propertyName - one of the property names listed above
listener - the property change listener to be added
removePropertyChangeListener(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 remove PropertyChangeListeners that were registered for a specific bound property.
If propertyName or listener is null, no exception is thrown and no action is taken.
propertyName - a valid property name
listener - the PropertyChangeListener to be removed
addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener), getPropertyChangeListeners(java.lang.String), removePropertyChangeListener(java.beans.PropertyChangeListener)
public PropertyChangeListener[] getPropertyChangeListeners(String propertyName)
PropertyChangeListeners associated with the named property; if no such listeners have been added or if propertyName is null, an empty array is returned
addPropertyChangeListener(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 changed
oldValue - the property's previous value
newValue - the property's new value
protected void firePropertyChange(String propertyName,
boolean oldValue,
boolean newValue)
propertyName - the property whose value has changed
oldValue - the property's previous value
newValue - the property's new value
protected void firePropertyChange(String propertyName,
int oldValue,
int newValue)
propertyName - the property whose value has changed
oldValue - the property's previous value
newValue - the property's new value
public void firePropertyChange(String propertyName,
byte oldValue,
byte newValue)
propertyName - the programmatic name of the property that was changed
oldValue - 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 changed
oldValue - 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 changed
oldValue - 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 changed
oldValue - 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 changed
oldValue - 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 changed
oldValue - 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 and Component subclasses will use this property to determine how to lay out and draw components.
At construction time, a component's orientation is set to ComponentOrientation.UNKNOWN, indicating that it has not been specified explicitly. The UNKNOWN orientation behaves the same as ComponentOrientation.LEFT_TO_RIGHT.
To set the orientation of a single component, use this method. To set the orientation of an entire component hierarchy, use applyComponentOrientation.
ComponentOrientation
public ComponentOrientation getComponentOrientation()
LayoutManager and Component 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.
orientation - the new component orientation of this component and the components contained within it.
NullPointerException - if orientation is null.
setComponentOrientation(java.awt.ComponentOrientation), getComponentOrientation()
public AccessibleContext getAccessibleContext()
AccessibleContext associated with this Component. The method implemented by this base class returns null. Classes that extend Component should implement this method to return the AccessibleContext associated with the subclass.
AccessibleContext of this Component
Copyright © 2004, 2010 Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
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