public class Applet extends Panel
The Applet
class must be the superclass of any
applet that is to be embedded in a Web page or viewed by the Java
Applet Viewer. The Applet
class provides a standard
interface between applets and their environment.
Modifier and Type | Class and Description |
---|---|
protected class |
Applet.AccessibleApplet
This class implements accessibility support for the
Applet class. |
Panel.AccessibleAWTPanel
Container.AccessibleAWTContainer
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor and Description |
---|
Applet()
Constructs a new Applet.
|
Modifier and Type | Method and Description |
---|---|
void |
destroy()
Called by the browser or applet viewer to inform
this applet that it is being reclaimed and that it should destroy
any resources that it has allocated.
|
AccessibleContext |
getAccessibleContext()
Gets the AccessibleContext associated with this Applet.
|
AppletContext |
getAppletContext()
Determines this applet's context, which allows the applet to
query and affect the environment in which it runs.
|
String |
getAppletInfo()
Returns information about this applet.
|
AudioClip |
getAudioClip(URL url)
Returns the
AudioClip object specified by the
URL argument. |
AudioClip |
getAudioClip(URL url,
String name)
Returns the
AudioClip object specified by the
URL and name arguments. |
URL |
getCodeBase()
Gets the base URL.
|
URL |
getDocumentBase()
Gets the URL of the document in which this applet is embedded.
|
Image |
getImage(URL url)
Returns an
Image object that can then be painted on
the screen. |
Image |
getImage(URL url,
String name)
Returns an
Image object that can then be painted on
the screen. |
Locale |
getLocale()
Gets the locale of the applet.
|
String |
getParameter(String name)
Returns the value of the named parameter in the HTML tag.
|
String[][] |
getParameterInfo()
Returns information about the parameters that are understood by
this applet.
|
void |
init()
Called by the browser or applet viewer to inform
this applet that it has been loaded into the system.
|
boolean |
isActive()
Determines if this applet is active.
|
boolean |
isValidateRoot()
Indicates if this container is a validate root.
|
static AudioClip |
newAudioClip(URL url)
Get an audio clip from the given URL.
|
void |
play(URL url)
Plays the audio clip at the specified absolute URL.
|
void |
play(URL url,
String name)
Plays the audio clip given the URL and a specifier that is
relative to it.
|
void |
resize(Dimension d)
Requests that this applet be resized.
|
void |
resize(int width,
int height)
Requests that this applet be resized.
|
void |
setStub(AppletStub stub)
Sets this applet's stub.
|
void |
showStatus(String msg)
Requests that the argument string be displayed in the
"status window".
|
void |
start()
Called by the browser or applet viewer to inform
this applet that it should start its execution.
|
void |
stop()
Called by the browser or applet viewer to inform
this applet that it should stop its execution.
|
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getMousePosition, getPreferredSize, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paint, paintComponents, paramString, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, removeNotify, setComponentZOrder, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setFont, setLayout, transferFocusDownCycle, update, validate, validateTree
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
public Applet() throws HeadlessException
Note: Many methods in java.applet.Applet
may be invoked by the applet only after the applet is
fully constructed; applet should avoid calling methods
in java.applet.Applet
in the constructor.
HeadlessException
- if GraphicsEnvironment.isHeadless()
returns true.GraphicsEnvironment.isHeadless()
public final void setStub(AppletStub stub)
If there is a security manager, its checkPermission
method is called with the
AWTPermission("setAppletStub")
permission if a stub has already been set.
stub
- the new stub.SecurityException
- if the caller cannot set the stubpublic boolean isActive()
start
method is called. It becomes
inactive just before its stop
method is called.public URL getDocumentBase()
The document base is:http://www.oracle.com/technetwork/java/index.html
http://www.oracle.com/technetwork/java/index.html
URL
of the document that contains this
applet.getCodeBase()
public URL getCodeBase()
URL
of
the directory which contains this applet.getDocumentBase()
public String getParameter(String name)
<applet code="Clock" width=50 height=50> <param name=Color value="blue"> </applet>
then a call to getParameter("Color")
returns the
value "blue"
.
The name
argument is case insensitive.
name
- a parameter name.null
if not set.public AppletContext getAppletContext()
This environment of an applet represents the document that contains the applet.
public void resize(int width, int height)
public void resize(Dimension d)
public boolean isValidateRoot()
Applet
objects are the validate roots, and, therefore, they
override this method to return true
.
isValidateRoot
in class Container
true
Container.isValidateRoot()
public void showStatus(String msg)
msg
- a string to display in the status window.public Image getImage(URL url)
Image
object that can then be painted on
the screen. The url
that is passed as an argument
must specify an absolute URL.
This method always returns immediately, whether or not the image exists. When this applet attempts to draw the image on the screen, the data will be loaded. The graphics primitives that draw the image will incrementally paint on the screen.
url
- an absolute URL giving the location of the image.Image
public Image getImage(URL url, String name)
Image
object that can then be painted on
the screen. The url
argument must specify an absolute
URL. The name
argument is a specifier that is
relative to the url
argument.
This method always returns immediately, whether or not the image exists. When this applet attempts to draw the image on the screen, the data will be loaded. The graphics primitives that draw the image will incrementally paint on the screen.
url
- an absolute URL giving the base location of the image.name
- the location of the image, relative to the
url
argument.Image
public static final AudioClip newAudioClip(URL url)
url
- points to the audio clippublic AudioClip getAudioClip(URL url)
AudioClip
object specified by the
URL
argument.
This method always returns immediately, whether or not the audio clip exists. When this applet attempts to play the audio clip, the data will be loaded.
url
- an absolute URL giving the location of the audio clip.AudioClip
public AudioClip getAudioClip(URL url, String name)
AudioClip
object specified by the
URL
and name
arguments.
This method always returns immediately, whether or not the audio clip exists. When this applet attempts to play the audio clip, the data will be loaded.
url
- an absolute URL giving the base location of the
audio clip.name
- the location of the audio clip, relative to the
url
argument.AudioClip
public String getAppletInfo()
String
containing information
about the author, version, and copyright of the applet.
The implementation of this method provided by the
Applet
class returns null
.
public Locale getLocale()
getLocale
in class Component
Component.setLocale(java.util.Locale)
public String[][] getParameterInfo()
Strings
describing these parameters.
Each element of the array should be a set of three
Strings
containing the name, the type, and a
description. For example:
String pinfo[][] = { {"fps", "1-10", "frames per second"}, {"repeat", "boolean", "repeat image loop"}, {"imgs", "url", "images directory"} };
The implementation of this method provided by the
Applet
class returns null
.
public void play(URL url)
url
- an absolute URL giving the location of the audio clip.public void play(URL url, String name)
url
- an absolute URL giving the base location of the
audio clip.name
- the location of the audio clip, relative to the
url
argument.public void init()
start
method is
called.
A subclass of Applet
should override this method if
it has initialization to perform. For example, an applet with
threads would use the init
method to create the
threads and the destroy
method to kill them.
The implementation of this method provided by the
Applet
class does nothing.
public void start()
init
method and each time the applet is revisited
in a Web page.
A subclass of Applet
should override this method if
it has any operation that it wants to perform each time the Web
page containing it is visited. For example, an applet with
animation might want to use the start
method to
resume animation, and the stop
method to suspend the
animation.
Note: some methods, such as getLocationOnScreen
, can only
provide meaningful results if the applet is showing. Because
isShowing
returns false
when the applet's
start
is first called, methods requiring
isShowing
to return true
should be called from
a ComponentListener
.
The implementation of this method provided by the
Applet
class does nothing.
public void stop()
A subclass of Applet
should override this method if
it has any operation that it wants to perform each time the Web
page containing it is no longer visible. For example, an applet
with animation might want to use the start
method to
resume animation, and the stop
method to suspend the
animation.
The implementation of this method provided by the
Applet
class does nothing.
public void destroy()
stop
method
will always be called before destroy
.
A subclass of Applet
should override this method if
it has any operation that it wants to perform before it is
destroyed. For example, an applet with threads would use the
init
method to create the threads and the
destroy
method to kill them.
The implementation of this method provided by the
Applet
class does nothing.
public AccessibleContext getAccessibleContext()
getAccessibleContext
in interface Accessible
getAccessibleContext
in class Panel
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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