javax.swing
Class JFrame

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--java.awt.Window
                    |
                    +--java.awt.Frame
                          |
                          +--javax.swing.JFrame

All Implemented Interfaces:

Accessible, ImageObserver, MenuContainer, RootPaneContainer, Serializable, WindowConstants

public class JFrame

extends Frame

implements WindowConstants, Accessible, RootPaneContainer

An extended version of java.awt.Frame that adds support for the JFC/Swing component architecture. You can find task-oriented documentation about using JFrame in The Java Tutorial, in the section How to Make Frames.

The JFrame class is slightly incompatible with Frame. Like all other JFC/Swing top-level containers, a JFrame contains a JRootPane as its only child. The content pane provided by the root pane should, as a rule, contain all the non-menu components displayed by the JFrame. This is different from the AWT Frame case. For example, to add a child to an AWT frame you'd write:

       frame.add(child);
 

However using JFrame you need to add the child to the JFrame's content pane instead:

       frame.getContentPane().add(child);
 

The same is true for setting layout managers, removing components, listing children, and so on. All these methods should normally be sent to the content pane instead of the JFrame itself. The content pane will always be non-null. Attempting to set it to null will cause the JFrame to throw an exception. The default content pane will have a BorderLayout manager set on it.

Unlike a Frame, a JFrame has some notion of how to respond when the user attempts to close the window. The default behavior is to simply hide the JFrame when the user closes the window. To change the default behavior, you invoke the method setDefaultCloseOperation(int). To make the JFrame behave the same as a Frame instance, use setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE).

For more information on content panes and other features that root panes provide, see Using Top-Level Containers in The Java Tutorial.

In a multi-screen environment, you can create a JFrame on a different screen device. See Frame for more information.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JFrame key assignments.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. A future release of Swing will provide support for long term persistence.

See Also:

JRootPane, setDefaultCloseOperation(int), WindowListener.windowClosing(java.awt.event.WindowEvent), Serialized Form

Inner Class Summary

protected class

JFrame.AccessibleJFrame This class implements accessibility support for the JFrame class.

Inner classes inherited from class java.awt.Frame

Frame.AccessibleAWTFrame

Inner classes inherited from class java.awt.Window

Window.AccessibleAWTWindow

Inner classes inherited from class java.awt.Container

Container.AccessibleAWTContainer

Inner classes inherited from class java.awt.Component

Component.AccessibleAWTComponent

Field Summary

protected AccessibleContext	accessibleContext The accessible context property.
static int	EXIT_ON_CLOSE The exit application default window close operation.
protected JRootPane	rootPane The JRootPane instance that manages the contentPane and optional menuBar for this frame, as well as the glassPane.
protected boolean	rootPaneCheckingEnabled If true then calls to add and setLayout will cause an exception to be thrown.

Fields inherited from class java.awt.Frame

CROSSHAIR_CURSOR, DEFAULT_CURSOR, E_RESIZE_CURSOR, HAND_CURSOR, ICONIFIED, MOVE_CURSOR, N_RESIZE_CURSOR, NE_RESIZE_CURSOR, NORMAL, NW_RESIZE_CURSOR, S_RESIZE_CURSOR, SE_RESIZE_CURSOR, SW_RESIZE_CURSOR, TEXT_CURSOR, W_RESIZE_CURSOR, WAIT_CURSOR

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface javax.swing.WindowConstants

DISPOSE_ON_CLOSE, DO_NOTHING_ON_CLOSE, HIDE_ON_CLOSE

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

JFrame()
Constructs a new frame that is initially invisible.

JFrame(GraphicsConfiguration gc)
Creates a Frame in the specified GraphicsConfiguration of a screen device and a blank title.

JFrame(String title)
Creates a new, initially invisible Frame with the specified title.

JFrame(String title, GraphicsConfiguration gc)
Creates a JFrame with the specified title and the specified GraphicsConfiguration of a screen device.

Method Summary

protected void	addImpl(Component comp, Object constraints, int index) By default, children may not be added directly to this component, they must be added to its contentPane instead.
protected JRootPane	createRootPane() Called by the constructor methods to create the default rootPane.
protected void	frameInit() Called by the constructors to init the JFrame properly.
AccessibleContext	getAccessibleContext() Gets the AccessibleContext associated with this JFrame.
Container	getContentPane() Returns the contentPane object for this frame.
int	getDefaultCloseOperation() Returns the operation that occurs when the user initiates a "close" on this frame.
Component	getGlassPane() Returns the glassPane object for this frame.
JMenuBar	getJMenuBar() Returns the menubar set on this frame.
JLayeredPane	getLayeredPane() Returns the layeredPane object for this frame.
JRootPane	getRootPane() Returns the rootPane object for this frame.
protected boolean	isRootPaneCheckingEnabled() Returns whether calls to add and setLayout cause an exception to be thrown.
protected String	paramString() Returns a string representation of this JFrame.
protected void	processKeyEvent(KeyEvent e) Processes key events occurring on this component and, if appropriate, passes them on to components in the frame which have registered interest in them.
protected void	processWindowEvent(WindowEvent e) Processes window events occurring on this component.
void	remove(Component comp) Removes the specified component from this container.
void	setContentPane(Container contentPane) Sets the contentPane property.
void	setDefaultCloseOperation(int operation) Sets the operation that will happen by default when the user initiates a "close" on this frame.
void	setGlassPane(Component glassPane) Sets the glassPane property.
void	setJMenuBar(JMenuBar menubar) Sets the menubar for this frame.
void	setLayeredPane(JLayeredPane layeredPane) Sets the layeredPane property.
void	setLayout(LayoutManager manager) By default the layout of this component may not be set, the layout of its contentPane should be set instead.
protected void	setRootPane(JRootPane root) Sets the rootPane property.
protected void	setRootPaneCheckingEnabled(boolean enabled) Determines whether calls to add and setLayout will cause an exception to be thrown.
void	update(Graphics g) Just calls paint(g).

Methods inherited from class java.awt.Frame

addNotify, finalize, getCursorType, getFrames, getIconImage, getMenuBar, getState, getTitle, isResizable, remove, removeNotify, setCursor, setIconImage, setMenuBar, setResizable, setState, setTitle

Methods inherited from class java.awt.Window

addWindowListener, applyResourceBundle, applyResourceBundle, dispose, getFocusOwner, getGraphicsConfiguration, getInputContext, getListeners, getLocale, getOwnedWindows, getOwner, getToolkit, getWarningString, hide, isShowing, pack, postEvent, processEvent, removeWindowListener, setCursor, show, toBack, toFront

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getInsets, getLayout, getMaximumSize, getMinimumSize, getPreferredSize, insets, invalidate, isAncestorOf, layout, list, list, locate, minimumSize, paint, paintComponents, preferredSize, print, printComponents, processContainerEvent, remove, removeAll, removeContainerListener, setFont, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addPropertyChangeListener, addPropertyChangeListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, getBackground, getBounds, getBounds, getColorModel, getComponentOrientation, getCursor, getDropTarget, getFont, getFontMetrics, getForeground, getGraphics, getHeight, getInputMethodRequests, getLocation, getLocation, getLocationOnScreen, getName, getParent, getPeer, getSize, getSize, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isDisplayable, isDoubleBuffered, isEnabled, isFocusTraversable, isLightweight, isOpaque, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseEvent, processMouseMotionEvent, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setDropTarget, setEnabled, setForeground, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, size, toString, transferFocus

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.awt.MenuContainer

getFont, postEvent

Field Detail

EXIT_ON_CLOSE

public static final int EXIT_ON_CLOSE

The exit application default window close operation. If a window has this set as the close operation and is closed in an applet, a SecurityException may be thrown. It is recommended you only use this in an application.

Since:

1.3

rootPane

protected JRootPane rootPane

The JRootPane instance that manages the contentPane and optional menuBar for this frame, as well as the glassPane.

See Also:

JRootPane, RootPaneContainer

rootPaneCheckingEnabled

protected boolean rootPaneCheckingEnabled

If true then calls to add and setLayout will cause an exception to be thrown. The default is false.

See Also:

isRootPaneCheckingEnabled(), setRootPaneCheckingEnabled(boolean)

accessibleContext

protected AccessibleContext accessibleContext

The accessible context property.

Constructor Detail

JFrame

public JFrame()

Constructs a new frame that is initially invisible.

See Also:

Component.setSize(int, int), Component.setVisible(boolean)

JFrame

public JFrame(GraphicsConfiguration gc)

Creates a Frame in the specified GraphicsConfiguration of a screen device and a blank title.

Parameters:

gc - the GraphicsConfiguration that is used to construct the new Frame; if gc is null, the system default GraphicsConfiguration is assumed

Throws:

IllegalArgumentException - if gc is not from a screen device

Since:

1.3

JFrame

public JFrame(String title)

Creates a new, initially invisible Frame with the specified title.

Parameters:

title - the title for the frame

See Also:

Component.setSize(int, int), Component.setVisible(boolean)

JFrame

public JFrame(String title,
              GraphicsConfiguration gc)

Creates a JFrame with the specified title and the specified GraphicsConfiguration of a screen device.

Parameters:

title - the title to be displayed in the frame's border. A null value is treated as an empty string, "".

gc - the GraphicsConfiguration that is used to construct the new JFrame with; if gc is null, the system default GraphicsConfiguration is assumed

Throws:

IllegalArgumentException - if gc is not from a screen device

Since:

1.3

Method Detail

frameInit

protected void frameInit()

Called by the constructors to init the JFrame properly.

createRootPane

protected JRootPane createRootPane()

Called by the constructor methods to create the default rootPane.

processKeyEvent

protected void processKeyEvent(KeyEvent e)

Processes key events occurring on this component and, if appropriate, passes them on to components in the frame which have registered interest in them.

Overrides:

processKeyEvent in class Component

Parameters:

e - the key event

See Also:

Component.processKeyEvent(java.awt.event.KeyEvent)

processWindowEvent

protected void processWindowEvent(WindowEvent e)

Processes window events occurring on this component. Hides the window or disposes of it, as specified by the setting of the defaultCloseOperation property.

Overrides:

processWindowEvent in class Window

Parameters:

e - the window event

See Also:

setDefaultCloseOperation(int), Window.processWindowEvent(java.awt.event.WindowEvent)

setDefaultCloseOperation

public void setDefaultCloseOperation(int operation)

Sets the operation that will happen by default when the user initiates a "close" on this frame. You must specify one of the following choices:

• DO_NOTHING_ON_CLOSE (defined in WindowConstants): Don't do anything; require the program to handle the operation in the windowClosing method of a registered WindowListener object.
• HIDE_ON_CLOSE (defined in WindowConstants): Automatically hide the frame after invoking any registered WindowListener objects.
• DISPOSE_ON_CLOSE (defined in WindowConstants): Automatically hide and dispose the frame after invoking any registered WindowListener objects.
• EXIT_ON_CLOSE (defined in JFrame): Exit the application using the System exit method. Use this only in applications.

The value is set to HIDE_ON_CLOSE by default.

See Also:

Window.addWindowListener(java.awt.event.WindowListener), getDefaultCloseOperation(), WindowConstants

getDefaultCloseOperation

public int getDefaultCloseOperation()

Returns the operation that occurs when the user initiates a "close" on this frame.

Returns:

an integer indicating the window-close operation

See Also:

setDefaultCloseOperation(int)

update

public void update(Graphics g)

Just calls paint(g). This method was overridden to prevent an unnecessary call to clear the background.

Overrides:

update in class Container

Parameters:

g - the Graphics context in which to paint

setJMenuBar

public void setJMenuBar(JMenuBar menubar)

Sets the menubar for this frame.

Parameters:

menubar - the menubar being placed in the frame

See Also:

getJMenuBar()

getJMenuBar

public JMenuBar getJMenuBar()

Returns the menubar set on this frame.

Returns:

the menubar for this frame

See Also:

setJMenuBar(javax.swing.JMenuBar)

isRootPaneCheckingEnabled

protected boolean isRootPaneCheckingEnabled()

Returns whether calls to add and setLayout cause an exception to be thrown.

Returns:

true if add and setLayout are checked; false otherwise

See Also:

addImpl(java.awt.Component, java.lang.Object, int), setLayout(java.awt.LayoutManager), setRootPaneCheckingEnabled(boolean)

setRootPaneCheckingEnabled

protected void setRootPaneCheckingEnabled(boolean enabled)

Determines whether calls to add and setLayout will cause an exception to be thrown.

Parameters:

enabled - true if checking is to be enabled, which causes the exceptions to be thrown

See Also:

addImpl(java.awt.Component, java.lang.Object, int), setLayout(java.awt.LayoutManager), isRootPaneCheckingEnabled()

addImpl

protected void addImpl(Component comp,
                       Object constraints,
                       int index)

By default, children may not be added directly to this component, they must be added to its contentPane instead. For example:

 thisComponent.getContentPane().add(child)
 

An attempt to add to directly to this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

Overrides:

addImpl in class Container

Parameters:

comp - the component to be enhanced

constraints - the constraints to be respected

index - the index

Throws:

Error - if called with rootPaneChecking true

See Also:

setRootPaneCheckingEnabled(boolean)

remove

public void remove(Component comp)

Removes the specified component from this container.

Overrides:

remove in class Container

Parameters:

comp - the component to be removed

See Also:

Container.add(java.awt.Component)

setLayout

public void setLayout(LayoutManager manager)

By default the layout of this component may not be set, the layout of its contentPane should be set instead. For example:

 thiComponent.getContentPane().setLayout(new BorderLayout())
 

An attempt to set the layout of this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

Overrides:

setLayout in class Container

Parameters:

manager - the LayoutManager

Throws:

Error - if called with rootPaneChecking true

See Also:

setRootPaneCheckingEnabled(boolean)

getRootPane

public JRootPane getRootPane()

Returns the rootPane object for this frame.

Specified by:

getRootPane in interface RootPaneContainer

Returns:

the rootPane property

See Also:

setRootPane(javax.swing.JRootPane), RootPaneContainer.getRootPane()

setRootPane

protected void setRootPane(JRootPane root)

Sets the rootPane property. This method is called by the constructor.

Parameters:

root - the rootPane object for this frame

See Also:

getRootPane()

getContentPane

public Container getContentPane()

Returns the contentPane object for this frame.

Specified by:

getContentPane in interface RootPaneContainer

Returns:

the contentPane property

See Also:

setContentPane(java.awt.Container), RootPaneContainer.getContentPane()

setContentPane

public void setContentPane(Container contentPane)

Sets the contentPane property. This method is called by the constructor.

Specified by:

setContentPane in interface RootPaneContainer

Parameters:

contentPane - the contentPane object for this frame

Throws:

IllegalComponentStateException - (a runtime exception) if the content pane parameter is null

See Also:

getContentPane(), RootPaneContainer.setContentPane(java.awt.Container)

getLayeredPane

public JLayeredPane getLayeredPane()

Returns the layeredPane object for this frame.

Specified by:

getLayeredPane in interface RootPaneContainer

Returns:

the layeredPane property

See Also:

setLayeredPane(javax.swing.JLayeredPane), RootPaneContainer.getLayeredPane()

setLayeredPane

public void setLayeredPane(JLayeredPane layeredPane)

Sets the layeredPane property. This method is called by the constructor.

Specified by:

setLayeredPane in interface RootPaneContainer

Parameters:

layeredPane - the layeredPane object for this frame

Throws:

IllegalComponentStateException - (a runtime exception) if the layered pane parameter is null

See Also:

getLayeredPane(), RootPaneContainer.setLayeredPane(javax.swing.JLayeredPane)

getGlassPane

public Component getGlassPane()

Returns the glassPane object for this frame.

Specified by:

getGlassPane in interface RootPaneContainer

Returns:

the glassPane property

See Also:

setGlassPane(java.awt.Component), RootPaneContainer.getGlassPane()

setGlassPane

public void setGlassPane(Component glassPane)

Sets the glassPane property. This method is called by the constructor.

Specified by:

setGlassPane in interface RootPaneContainer

Parameters:

glassPane - the glassPane object for this frame

See Also:

getGlassPane(), RootPaneContainer.setGlassPane(java.awt.Component)

paramString

protected String paramString()

Returns a string representation of this JFrame. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:

paramString in class Frame

Returns:

a string representation of this JFrame

getAccessibleContext

public AccessibleContext getAccessibleContext()

Gets the AccessibleContext associated with this JFrame. For JFrames, the AccessibleContext takes the form of an AccessibleJFrame. A new AccessibleJFrame instance is created if necessary.

Specified by:

getAccessibleContext in interface Accessible

Overrides:

getAccessibleContext in class Frame

Returns:

an AccessibleJFrame that serves as the AccessibleContext of this JFrame