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. As a convenience, the add, remove, and setLayout methods of this class are overridden, so that they delegate calls to the corresponding methods of the ContentPane. For example, you can add a child component to a frame as follows:
frame.add(child);And the child will be added to the contentPane. 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. Refer to
RootPaneContainer for details on adding, removing and setting the LayoutManager of a JFrame. 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.
Warning: Swing is not thread safe. For more information see Swing's Threading Policy.
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™ has been added to the java.beans package. Please see XMLEncoder.
JRootPane, setDefaultCloseOperation(int), WindowListener.windowClosing(java.awt.event.WindowEvent), RootPaneContainer
| Modifier and Type | Class and Description |
|---|---|
protected class |
JFrame.AccessibleJFrame This class implements accessibility support for the |
Frame.AccessibleAWTFrame Window.AccessibleAWTWindow, Window.Type Container.AccessibleAWTContainer Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy 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.
protected JRootPane rootPane
The JRootPane instance that manages the contentPane and optional menuBar for this frame, as well as the glassPane.
JRootPane, RootPaneContainer
protected boolean rootPaneCheckingEnabled
If true then calls to add and setLayout will be forwarded to the contentPane. This is initially false, but is set to true when the JFrame is constructed.
protected AccessibleContext accessibleContext
The accessible context property.
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.
HeadlessException - if GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless(), Component.setSize(int, int), Component.setVisible(boolean), JComponent.getDefaultLocale()
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.
gc - the GraphicsConfiguration that is used to construct the new Frame; if gc is null, the system default GraphicsConfiguration is assumedIllegalArgumentException - 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 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.
title - the title for the frameHeadlessException - if GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless(), Component.setSize(int, int), Component.setVisible(boolean), JComponent.getDefaultLocale()
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.
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 assumedIllegalArgumentException - if gc is not from a screen device. This exception is always thrown when GraphicsEnvironment.isHeadless() returns true.GraphicsEnvironment.isHeadless(), JComponent.getDefaultLocale()
protected void frameInit()
Called by the constructors to init the JFrame properly.
protected JRootPane createRootPane()
Called by the constructor methods to create the default rootPane.
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.
processWindowEvent in class Window
e - the window eventsetDefaultCloseOperation(int), Window.processWindowEvent(java.awt.event.WindowEvent)
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. Changes to the value of this property cause the firing of a property change event, with property name "defaultCloseOperation".
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 frameIllegalArgumentException - if defaultCloseOperation value isn't one of the above valid valuesSecurityException - 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()
Returns the operation that occurs when the user initiates a "close" on this frame.
setDefaultCloseOperation(int)public void setTransferHandler(TransferHandler newHandler)
Sets the transferHandler property, which is a mechanism to support transfer of data into this component. Use null if the component does not support data transfer operations.
If the system property suppressSwingDropSupport is false (the default) and the current drop target on this component is either null or not a user-set drop target, this method will change the drop target as follows: If newHandler is null it will clear the drop target. If not null it will install a new DropTarget.
Note: When used with JFrame, TransferHandler only provides data import capability, as the data export related methods are currently typed to JComponent.
Please see How to Use Drag and Drop and Data Transfer, a section in The Java Tutorial, for more information.
newHandler - the new TransferHandler
TransferHandler, getTransferHandler(), Component.setDropTarget(java.awt.dnd.DropTarget)
public TransferHandler getTransferHandler()
Gets the transferHandler property.
transferHandler propertyTransferHandler, setTransferHandler(javax.swing.TransferHandler)
public void update(Graphics g)
Just calls 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)
Sets the menubar for this frame.
menubar - the menubar being placed in the framegetJMenuBar()public JMenuBar getJMenuBar()
Returns the menubar set on this frame.
setJMenuBar(javax.swing.JMenuBar)protected boolean isRootPaneCheckingEnabled()
Returns whether calls to add and setLayout are forwarded to the contentPane.
add and setLayout are forwarded; false otherwiseaddImpl(java.awt.Component, java.lang.Object, int), setLayout(java.awt.LayoutManager), setRootPaneCheckingEnabled(boolean), RootPaneContainer
protected void setRootPaneCheckingEnabled(boolean enabled)
Sets whether calls to add and setLayout are forwarded to the contentPane.
enabled - true if add and setLayout are forwarded, false if they should operate directly on the JFrame.addImpl(java.awt.Component, java.lang.Object, int), setLayout(java.awt.LayoutManager), isRootPaneCheckingEnabled(), RootPaneContainer
protected void addImpl(Component comp,
Object constraints,
int index) Adds the specified child Component. This method is overridden to conditionally forward calls to the contentPane. By default, children are added to the contentPane instead of the frame, refer to RootPaneContainer for details.
addImpl in class Container
comp - the component to be enhancedconstraints - the constraints to be respectedindex - the indexIllegalArgumentException - if index is invalidIllegalArgumentException - if adding the container's parent to itselfIllegalArgumentException - if adding a window to a containersetRootPaneCheckingEnabled(boolean), RootPaneContainer
public void remove(Component comp)
Removes the specified component from the container. If comp is not the rootPane, this will forward the call to the contentPane. This will do nothing if comp is not a child of the JFrame or contentPane.
remove in class Container
comp - the component to be removedNullPointerException - if comp is nullContainer.add(java.awt.Component), RootPaneContainer
public void setLayout(LayoutManager manager)
Sets the LayoutManager. Overridden to conditionally forward the call to the contentPane. Refer to RootPaneContainer for more information.
setLayout in class Container
manager - the LayoutManager
setRootPaneCheckingEnabled(boolean), RootPaneContainer
public JRootPane getRootPane()
Returns the rootPane object for this frame.
getRootPane in interface RootPaneContainer
rootPane propertysetRootPane(javax.swing.JRootPane), RootPaneContainer.getRootPane()
protected void setRootPane(JRootPane root)
Sets the rootPane property. This method is called by the constructor.
root - the rootPane object for this framegetRootPane()public void setIconImage(Image image)
Sets the image to be displayed as the icon for this window.
This method can be used instead of setIconImages() to specify a single image as a window's icon.
The following statement:
setIconImage(image);is equivalent to:
ArrayList<Image> imageList = new ArrayList<Image>();
imageList.add(image);
setIconImages(imageList); Note : Native windowing systems may use different images of differing dimensions to represent a window, depending on the context (e.g. window decoration, window list, taskbar, etc.). They could also use just a single image for all contexts or no image at all.
setIconImage in class Frame
image - the icon image to be displayed.Window.setIconImages(java.util.List<? extends java.awt.Image>), Window.getIconImages()
public Container getContentPane()
Returns the contentPane object for this frame.
getContentPane in interface RootPaneContainer
contentPane propertysetContentPane(java.awt.Container), RootPaneContainer.getContentPane()
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 hierarchy. 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 frameIllegalComponentStateException - (a runtime exception) if the content pane parameter is null
getContentPane(), RootPaneContainer.setContentPane(java.awt.Container), JRootPane
public JLayeredPane getLayeredPane()
Returns the layeredPane object for this frame.
getLayeredPane in interface RootPaneContainer
layeredPane propertysetLayeredPane(javax.swing.JLayeredPane), RootPaneContainer.getLayeredPane()
public void setLayeredPane(JLayeredPane layeredPane)
Sets the layeredPane property. This method is called by the constructor.
setLayeredPane in interface RootPaneContainer
layeredPane - the layeredPane object for this frameIllegalComponentStateException - (a runtime exception) if the layered pane parameter is null
getLayeredPane(), RootPaneContainer.setLayeredPane(javax.swing.JLayeredPane)
public Component getGlassPane()
Returns the glassPane object for this frame.
getGlassPane in interface RootPaneContainer
glassPane propertysetGlassPane(java.awt.Component), RootPaneContainer.getGlassPane()
public void setGlassPane(Component glassPane)
Sets the 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 Graphics getGraphics()
Creates a graphics context for this component. This method will return null if this component is currently not displayable.
getGraphics in class Component
null if it has noneComponent.paint(java.awt.Graphics)public void repaint(long time,
int x,
int y,
int width,
int height) Repaints the specified rectangle of this component within time milliseconds. Refer to RepaintManager for details on how the repaint is handled.
repaint in class Component
time - maximum time in milliseconds before updatex - the x coordinatey - the y coordinatewidth - the widthheight - the heightRepaintManagerpublic 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);
defaultLookAndFeelDecorated - A hint as to whether or not current look and feel should provide window decorationsLookAndFeel.getSupportsWindowDecorations()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.
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.
paramString in class Frame
JFrame
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.
getAccessibleContext in interface Accessible
getAccessibleContext in class Frame
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