JFrame

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. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see XMLEncoder.

See Also:: JRootPane, setDefaultCloseOperation(int), WindowListener.windowClosing(java.awt.event.WindowEvent)

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,


      MAXIMIZED_BOTH,


      MAXIMIZED_HORIZ,


      MAXIMIZED_VERT,


      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.
`static boolean`	`isDefaultLookAndFeelDecorated()` Returns true if newly created `JFrame`s should have their Window decorations provided by the current look and feel.
`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`	`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.
`static void`	`setDefaultLookAndFeelDecorated(boolean defaultLookAndFeelDecorated)` Provides a hint as to whether or not newly created `JFrame`s should have their Window decorations (such as borders, widgets to close the window, title...) provided by the current look and feel.
`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,


      getExtendedState,


      getFrames,


      getIconImage,


      getMaximizedBounds,


      getMenuBar,


      getState,


      getTitle,


      isResizable,


      isUndecorated,


      remove,


      removeNotify,


      setCursor,


      setExtendedState,


      setIconImage,


      setMaximizedBounds,


      setMenuBar,


      setResizable,


      setState,


      setTitle,


      setUndecorated

Methods inherited from class java.awt.Window

addPropertyChangeListener,


      addPropertyChangeListener,


      addWindowFocusListener,


      addWindowListener,


      addWindowStateListener,


      applyResourceBundle,


      applyResourceBundle,


      createBufferStrategy,


      createBufferStrategy,


      dispose,


      getBufferStrategy,


      getFocusableWindowState,


      getFocusCycleRootAncestor,


      getFocusOwner,


      getFocusTraversalKeys,


      getGraphicsConfiguration,


      getInputContext,


      getListeners,


      getLocale,


      getMostRecentFocusOwner,


      getOwnedWindows,


      getOwner,


      getToolkit,


      getWarningString,


      getWindowFocusListeners,


      getWindowListeners,


      getWindowStateListeners,


      hide,


      isActive,


      isFocusableWindow,


      isFocusCycleRoot,


      isFocused,


      isShowing,


      pack,


      postEvent,


      processEvent,


      processWindowFocusEvent,


      processWindowStateEvent,


      removeWindowFocusListener,


      removeWindowListener,


      removeWindowStateListener,


      setCursor,


      setFocusableWindowState,


      setFocusCycleRoot,


      setLocationRelativeTo,


      show,


      toBack,


      toFront

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
See Also:: Constant Field Values

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()
       throws HeadlessException

Constructs a new frame that is initially invisible.

This constructor sets the component's locale property to the value returned by JComponent.getDefaultLocale.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

GraphicsEnvironment.isHeadless(),

Component.setSize(int,
int)

, Component.setVisible(boolean), JComponent.getDefaultLocale()

JFrame

public JFrame(GraphicsConfiguration gc)

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

This constructor sets the component's locale property to the value returned by JComponent.getDefaultLocale.

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. This exception is always thrown when GraphicsEnvironment.isHeadless() returns true.

Since:

1.3

JFrame

public JFrame(String title)
       throws HeadlessException

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

This constructor sets the component's locale property to the value returned by JComponent.getDefaultLocale.

Parameters:

title - the title for the frame

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

See Also:

GraphicsEnvironment.isHeadless(),

Component.setSize(int,
int)

, Component.setVisible(boolean), JComponent.getDefaultLocale()

JFrame

public JFrame(String title,
              GraphicsConfiguration gc)

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

This constructor sets the component's locale property to the value returned by JComponent.getDefaultLocale.

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. This exception is always thrown when GraphicsEnvironment.isHeadless() returns true.

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.

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.

Note: When the last displayable window within the Java virtual machine (VM) is disposed of, the VM may terminate. See AWT Threading Issues for more information.

Parameters:: operation - the operation which should be performed when the user closes the frame
Throws:: IllegalArgumentException - if defaultCloseOperation value isn't one of the above valid values; SecurityException - if EXIT_ON_CLOSE has been specified and the SecurityManager will not allow the caller to invoke System.exit
See Also:: Window.addWindowListener(java.awt.event.WindowListener), getDefaultCloseOperation(), WindowConstants, Runtime.exit(int)

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
See Also:: Component.update(Graphics)

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:

 thisComponent.getContentPane().setLayout(new GridLayout(1, 2))

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.

Swing's painting architecture requires an opaque JComponent in the containment hiearchy. This is typically provided by the content pane. If you replace the content pane it is recommended you replace it with an opaque JComponent.

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), JRootPane

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)

setDefaultLookAndFeelDecorated

public static void setDefaultLookAndFeelDecorated(boolean defaultLookAndFeelDecorated)

Provides a hint as to whether or not newly created JFrames should have their Window decorations (such as borders, widgets to close the window, title...) provided by the current look and feel. If defaultLookAndFeelDecorated is true, the current LookAndFeel supports providing window decorations, and the current window manager supports undecorated windows, then newly created JFrames will have their Window decorations provided by the current LookAndFeel. Otherwise, newly created JFrames will have their Window decorations provided by the current window manager.

You can get the same effect on a single JFrame by doing the following:

    JFrame frame = new JFrame();
    frame.setUndecorated(true);
    frame.getRootPane().setWindowDecorationStyle(JRootPane.FRAME);

Parameters:: defaultLookAndFeelDecorated - A hint as to whether or not current look and feel should provide window decorations
Since:: 1.4
See Also:: LookAndFeel.getSupportsWindowDecorations()

isDefaultLookAndFeelDecorated

public static boolean isDefaultLookAndFeelDecorated()

Returns true if newly created JFrames should have their Window decorations provided by the current look and feel. This is only a hint, as certain look and feels may not support this feature.

Returns:: true if look and feel should provide Window decorations.
Since:: 1.4

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

javax.swing Class JFrame

EXIT_ON_CLOSE

rootPane

rootPaneCheckingEnabled

accessibleContext

JFrame

JFrame

JFrame

JFrame

frameInit

createRootPane

processWindowEvent

setDefaultCloseOperation

getDefaultCloseOperation

update

setJMenuBar

getJMenuBar

isRootPaneCheckingEnabled

setRootPaneCheckingEnabled

addImpl

remove

setLayout

getRootPane

setRootPane

getContentPane

setContentPane

getLayeredPane

setLayeredPane

getGlassPane

setGlassPane

setDefaultLookAndFeelDecorated

isDefaultLookAndFeelDecorated

paramString

getAccessibleContext

javax.swing
Class JFrame