Class JFrame

java.lang.Object
java.awt.Component
java.awt.Container
java.awt.Window
java.awt.Frame
javax.swing.JFrame
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible, RootPaneContainer, WindowConstants
@JavaBean(defaultProperty="JMenuBar", description="A toplevel window which can be minimized to an icon.") 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.

Since:
1.2
See Also:

  • Field Details

  • Constructor Details

  • Method Details

    • 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.
      Returns:
      a new JRootPane

    • 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

      @BeanProperty(preferred=true, enumerationValues={"WindowConstants.DO_NOTHING_ON_CLOSE","WindowConstants.HIDE_ON_CLOSE","WindowConstants.DISPOSE_ON_CLOSE","WindowConstants.EXIT_ON_CLOSE"}, description="The frame's default close operation.") 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 WindowConstants): 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.

      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
      See Also:

    • 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:

    • setTransferHandler

      @BeanProperty(hidden=true, description="Mechanism for transfer of data into the component") 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.

      Parameters:
      newHandler - the new TransferHandler
      Since:
      1.6
      See Also:

    • getTransferHandler

      public TransferHandler getTransferHandler()
      Gets the transferHandler property.
      Returns:
      the value of the transferHandler property
      Since:
      1.6
      See Also:

    • 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:

    • setJMenuBar

      @BeanProperty(bound=false, hidden=true, description="The menubar for accessing pulldown menus from this frame.") public void setJMenuBar(JMenuBar menubar)
      Sets the menubar for this frame.
      Parameters:
      menubar - the menubar being placed in the frame
      See Also:

    • getJMenuBar

      public JMenuBar getJMenuBar()
      Returns the menubar set on this frame.
      Returns:
      the menubar for this frame
      See Also:

    • isRootPaneCheckingEnabled

      protected boolean isRootPaneCheckingEnabled()
      Returns whether calls to add and setLayout are forwarded to the contentPane.
      Returns:
      true if add and setLayout are forwarded; false otherwise
      See Also:

    • setRootPaneCheckingEnabled

      @BeanProperty(hidden=true, description="Whether the add and setLayout methods are forwarded") protected void setRootPaneCheckingEnabled(boolean enabled)
      Sets whether calls to add and setLayout are forwarded to the contentPane.
      Parameters:
      enabled - true if add and setLayout are forwarded, false if they should operate directly on the JFrame.
      See Also:

    • addImpl

      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.
      Overrides:
      addImpl in class Container
      Parameters:
      comp - the component to be enhanced
      constraints - the constraints to be respected
      index - the index
      Throws:
      IllegalArgumentException - if index is invalid
      IllegalArgumentException - if adding the container's parent to itself
      IllegalArgumentException - if adding a window to a container
      See Also:

    • remove

      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.
      Overrides:
      remove in class Container
      Parameters:
      comp - the component to be removed
      Throws:
      NullPointerException - if comp is null
      See Also:

    • setLayout

      public void setLayout(LayoutManager manager)
      Sets the LayoutManager. Overridden to conditionally forward the call to the contentPane. Refer to RootPaneContainer for more information.
      Overrides:
      setLayout in class Container
      Parameters:
      manager - the LayoutManager
      See Also:

    • getRootPane

      @BeanProperty(bound=false, hidden=true, description="the RootPane object for this frame.") public JRootPane getRootPane()
      Returns the rootPane object for this frame.
      Specified by:
      getRootPane in interface RootPaneContainer
      Returns:
      the rootPane property
      See Also:

    • 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:

    • getContentPane

      public Container getContentPane()
      Returns the contentPane object for this frame.
      Specified by:
      getContentPane in interface RootPaneContainer
      Returns:
      the contentPane property
      See Also:

    • setContentPane

      @BeanProperty(bound=false, hidden=true, description="The client area of the frame where child components are normally inserted.") 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.

      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:

    • getLayeredPane

      public JLayeredPane getLayeredPane()
      Returns the layeredPane object for this frame.
      Specified by:
      getLayeredPane in interface RootPaneContainer
      Returns:
      the layeredPane property
      See Also:

    • setLayeredPane

      @BeanProperty(bound=false, hidden=true, description="The pane that holds the various frame layers.") 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:

    • getGlassPane

      public Component getGlassPane()
      Returns the glassPane object for this frame.
      Specified by:
      getGlassPane in interface RootPaneContainer
      Returns:
      the glassPane property
      See Also:

    • setGlassPane

      @BeanProperty(bound=false, hidden=true, description="A transparent pane used for menu rendering.") 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:

    • getGraphics

      @BeanProperty(bound=false) public Graphics getGraphics()
      Creates a graphics context for this component. This method will return null if this component is currently not displayable.
      Overrides:
      getGraphics in class Component
      Returns:
      a graphics context for this component, or null if it has none
      Since:
      1.6
      See Also:

    • repaint

      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.
      Overrides:
      repaint in class Component
      Parameters:
      time - maximum time in milliseconds before update
      x - the x coordinate
      y - the y coordinate
      width - the width
      height - the height
      Since:
      1.6
      See Also:

    • 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:

    • 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