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java.lang.Object java.awt.Component java.awt.Container java.awt.Window java.awt.Frame javax.swing.JFrame
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 JavaBeansTM
has been added to the java.beans
package.
Please see XMLEncoder
.
JRootPane
,
setDefaultCloseOperation(int)
,
WindowListener.windowClosing(java.awt.event.WindowEvent)
,
Serialized FormNested Class Summary | |
protected class |
JFrame.AccessibleJFrame
This class implements accessibility support for the JFrame class. |
Nested classes inherited from class java.awt.Frame |
Frame.AccessibleAWTFrame |
Nested classes inherited from class java.awt.Window |
Window.AccessibleAWTWindow |
Nested classes inherited from class java.awt.Container |
Container.AccessibleAWTContainer |
Nested classes inherited from class java.awt.Component |
Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy |
Field Summary | |
protected javax.accessibility.AccessibleContext |
accessibleContext
The accessible context property. |
private int |
defaultCloseOperation
|
private static Object |
defaultLookAndFeelDecoratedKey
Key into the AppContext, used to check if should provide decorations by default. |
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.Window |
|
Fields inherited from class java.awt.Container |
|
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 . |
private Error |
createRootPaneException(String op)
Creates a runtime exception with a message like: "Do not use JFrame.add() use JFrame.getContentPane().add() instead" |
protected void |
frameInit()
Called by the constructors to init the JFrame properly. |
javax.accessibility.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.lang.Object |
clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface java.awt.MenuContainer |
getFont, postEvent |
Field Detail |
public static final int EXIT_ON_CLOSE
SecurityException
may be thrown.
It is recommended you only use this in an application.
private static final Object defaultLookAndFeelDecoratedKey
private int defaultCloseOperation
protected JRootPane rootPane
JRootPane
instance that manages the
contentPane
and optional menuBar
for this frame, as well as the
glassPane
.
JRootPane
,
RootPaneContainer
protected boolean rootPaneCheckingEnabled
add
and setLayout
will cause an exception to be thrown. The default is false.
isRootPaneCheckingEnabled()
,
setRootPaneCheckingEnabled(boolean)
protected javax.accessibility.AccessibleContext accessibleContext
Constructor Detail |
public JFrame() throws HeadlessException
This constructor sets the component's locale property to the value
returned by JComponent.getDefaultLocale
.
HeadlessException
- if GraphicsEnvironment.isHeadless()
returns true.GraphicsEnvironment.isHeadless()
,
Component.setSize(int, int)
,
Component.setVisible(boolean)
,
JComponent.getDefaultLocale()
public JFrame(GraphicsConfiguration gc)
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
.
gc
- the GraphicsConfiguration
that is used
to construct the new Frame
;
if gc
is null
, the system
default GraphicsConfiguration
is assumed
IllegalArgumentException
- if gc
is not from
a screen device. This exception is always thrown when
GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless()
,
JComponent.getDefaultLocale()
public JFrame(String title) throws HeadlessException
Frame
with the
specified title.
This constructor sets the component's locale property to the value
returned by JComponent.getDefaultLocale
.
title
- the title for the frame
HeadlessException
- if GraphicsEnvironment.isHeadless()
returns true.GraphicsEnvironment.isHeadless()
,
Component.setSize(int, int)
,
Component.setVisible(boolean)
,
JComponent.getDefaultLocale()
public JFrame(String title, GraphicsConfiguration gc)
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
.
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
IllegalArgumentException
- if gc
is not from
a screen device. This exception is always thrown when
GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless()
,
JComponent.getDefaultLocale()
Method Detail |
protected void frameInit()
JFrame
properly.
protected JRootPane createRootPane()
rootPane
.
protected void processWindowEvent(WindowEvent e)
defaultCloseOperation
property.
processWindowEvent
in class Window
e
- the window eventsetDefaultCloseOperation(int)
,
Window.processWindowEvent(java.awt.event.WindowEvent)
public void setDefaultCloseOperation(int operation)
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.
operation
- the operation which should be performed when the
user closes the frame
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
Window.addWindowListener(java.awt.event.WindowListener)
,
getDefaultCloseOperation()
,
WindowConstants
,
Runtime.exit(int)
public int getDefaultCloseOperation()
setDefaultCloseOperation(int)
public void update(Graphics g)
paint(g)
. This method was overridden to
prevent an unnecessary call to clear the background.
update
in class Container
g
- the Graphics context in which to paintComponent.update(Graphics)
public void setJMenuBar(JMenuBar menubar)
menubar
- the menubar being placed in the framegetJMenuBar()
public JMenuBar getJMenuBar()
setJMenuBar(javax.swing.JMenuBar)
protected boolean isRootPaneCheckingEnabled()
add
and
setLayout
cause an exception to be thrown.
add
and setLayout
are checked; false otherwiseaddImpl(java.awt.Component, java.lang.Object, int)
,
setLayout(java.awt.LayoutManager)
,
setRootPaneCheckingEnabled(boolean)
protected void setRootPaneCheckingEnabled(boolean enabled)
add
and
setLayout
will cause an exception to be thrown.
enabled
- true if checking is to be
enabled, which causes the exceptions to be thrownaddImpl(java.awt.Component, java.lang.Object, int)
,
setLayout(java.awt.LayoutManager)
,
isRootPaneCheckingEnabled()
private Error createRootPaneException(String op)
"Do not use JFrame.add() use JFrame.getContentPane().add() instead"
op
- a String
indicating the attempted operation;
in the example above, the operation string is "add"protected void addImpl(Component comp, Object constraints, int index)
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.
addImpl
in class Container
comp
- the component to be enhancedconstraints
- the constraints to be respectedindex
- the index
Error
- if called with rootPaneChecking
truesetRootPaneCheckingEnabled(boolean)
public void remove(Component comp)
remove
in class Container
comp
- the component to be removedContainer.add(java.awt.Component)
public void setLayout(LayoutManager manager)
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.
setLayout
in class Container
manager
- the LayoutManager
Error
- if called with rootPaneChecking
truesetRootPaneCheckingEnabled(boolean)
public JRootPane getRootPane()
rootPane
object for this frame.
getRootPane
in interface RootPaneContainer
rootPane
propertysetRootPane(javax.swing.JRootPane)
,
RootPaneContainer.getRootPane()
protected void setRootPane(JRootPane root)
rootPane
property.
This method is called by the constructor.
root
- the rootPane
object for this framegetRootPane()
public Container getContentPane()
contentPane
object for this frame.
getContentPane
in interface RootPaneContainer
contentPane
propertysetContentPane(java.awt.Container)
,
RootPaneContainer.getContentPane()
public void setContentPane(Container contentPane)
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
.
setContentPane
in interface RootPaneContainer
contentPane
- the contentPane
object for this frame
IllegalComponentStateException
- (a runtime
exception) if the content pane parameter is null
getContentPane()
,
RootPaneContainer.setContentPane(java.awt.Container)
,
JRootPane
public JLayeredPane getLayeredPane()
layeredPane
object for this frame.
getLayeredPane
in interface RootPaneContainer
layeredPane
propertysetLayeredPane(javax.swing.JLayeredPane)
,
RootPaneContainer.getLayeredPane()
public void setLayeredPane(JLayeredPane layeredPane)
layeredPane
property.
This method is called by the constructor.
setLayeredPane
in interface RootPaneContainer
layeredPane
- the layeredPane
object for this frame
IllegalComponentStateException
- (a runtime
exception) if the layered pane parameter is null
getLayeredPane()
,
RootPaneContainer.setLayeredPane(javax.swing.JLayeredPane)
public Component getGlassPane()
glassPane
object for this frame.
getGlassPane
in interface RootPaneContainer
glassPane
propertysetGlassPane(java.awt.Component)
,
RootPaneContainer.getGlassPane()
public void setGlassPane(Component glassPane)
glassPane
property.
This method is called by the constructor.
setGlassPane
in interface RootPaneContainer
glassPane
- the glassPane
object for this framegetGlassPane()
,
RootPaneContainer.setGlassPane(java.awt.Component)
public static void setDefaultLookAndFeelDecorated(boolean defaultLookAndFeelDecorated)
JFrame
s
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 JFrame
s will have their
Window decorations provided by the current LookAndFeel
.
Otherwise, newly created JFrame
s 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);
defaultLookAndFeelDecorated
- A hint as to whether or not current
look and feel should provide window decorationsLookAndFeel.getSupportsWindowDecorations()
public static boolean isDefaultLookAndFeelDecorated()
JFrame
s 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.
protected String paramString()
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
.
paramString
in class Frame
JFrame
public javax.accessibility.AccessibleContext getAccessibleContext()
getAccessibleContext
in interface javax.accessibility.Accessible
getAccessibleContext
in class Frame
|
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