JButton (Java Platform SE 8 )
Keywords: javax.swing.JButton class
Date: 2017-01-22

javax.swing

## Class JButton

- java.lang.Object
- - java.awt.Component
  - - java.awt.Container
    - - javax.swing.JComponent
      - - javax.swing.AbstractButton
        - - javax.swing.JButton

- All Implemented Interfaces:
    ImageObserver, ItemSelectable, MenuContainer, Serializable, Accessible, SwingConstants
  Direct Known Subclasses:
    BasicArrowButton, MetalComboBoxButton

      public class JButton
      extends AbstractButton
      implements Accessible

  An implementation of a "push" button.

  Buttons can be configured, and to some degree controlled, by `Action`s. Using an `Action` with a button has many benefits beyond directly configuring a button. Refer to Swing Components Supporting `Action` for more details, and you can find more information in How to Use Actions, a section in The Java Tutorial.

  See How to Use Buttons, Check Boxes, and Radio Buttons in The Java Tutorial for information and examples of using buttons.

  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`.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `protected class` | `JButton.AccessibleJButton` This class implements accessibility support for the `JButton` class.

    - ### Nested classes/interfaces inherited from class javax.swing.AbstractButton

      `AbstractButton.AccessibleAbstractButton, AbstractButton.ButtonChangeListener`

    - ### Nested classes/interfaces inherited from class javax.swing.JComponent

      `JComponent.AccessibleJComponent`

    - ### Nested classes/interfaces inherited from class java.awt.Container

      `Container.AccessibleAWTContainer`

    - ### Nested classes/interfaces inherited from class java.awt.Component

      `Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy`

  - ### Field Summary

    - ### Fields inherited from class javax.swing.AbstractButton

      `actionListener, BORDER_PAINTED_CHANGED_PROPERTY, changeEvent, changeListener, CONTENT_AREA_FILLED_CHANGED_PROPERTY, DISABLED_ICON_CHANGED_PROPERTY, DISABLED_SELECTED_ICON_CHANGED_PROPERTY, FOCUS_PAINTED_CHANGED_PROPERTY, HORIZONTAL_ALIGNMENT_CHANGED_PROPERTY, HORIZONTAL_TEXT_POSITION_CHANGED_PROPERTY, ICON_CHANGED_PROPERTY, itemListener, MARGIN_CHANGED_PROPERTY, MNEMONIC_CHANGED_PROPERTY, model, MODEL_CHANGED_PROPERTY, PRESSED_ICON_CHANGED_PROPERTY, ROLLOVER_ENABLED_CHANGED_PROPERTY, ROLLOVER_ICON_CHANGED_PROPERTY, ROLLOVER_SELECTED_ICON_CHANGED_PROPERTY, SELECTED_ICON_CHANGED_PROPERTY, TEXT_CHANGED_PROPERTY, VERTICAL_ALIGNMENT_CHANGED_PROPERTY, VERTICAL_TEXT_POSITION_CHANGED_PROPERTY`

    - ### Fields inherited from class javax.swing.JComponent

      `listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW`

    - ### Fields inherited from class java.awt.Component

      `accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT`

    - ### Fields inherited from interface javax.swing.SwingConstants

      `BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST`

    - ### Fields inherited from interface java.awt.image.ImageObserver

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

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `JButton()` Creates a button with no set text or icon.
    `JButton(Action a)` Creates a button where properties are taken from the `Action` supplied.
    `JButton(Icon icon)` Creates a button with an icon.
    `JButton(String text)` Creates a button with text.
    `JButton(String text, Icon icon)` Creates a button with initial text and an icon.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `AccessibleContext` | `getAccessibleContext()` Gets the `AccessibleContext` associated with this `JButton`.
    `String` | `getUIClassID()` Returns a string that specifies the name of the L&F class that renders this component.
    `boolean` | `isDefaultButton()` Gets the value of the `defaultButton` property, which if `true` means that this button is the current default button for its `JRootPane`.
    `boolean` | `isDefaultCapable()` Gets the value of the `defaultCapable` property.
    `protected String` | `paramString()` Returns a string representation of this `JButton`.
    `void` | `removeNotify()` Overrides `JComponent.removeNotify` to check if this button is currently set as the default button on the `RootPane`, and if so, sets the `RootPane`'s default button to `null` to ensure the `RootPane` doesn't hold onto an invalid button reference.
    `void` | `setDefaultCapable(boolean defaultCapable)` Sets the `defaultCapable` property, which determines whether this button can be made the default button for its root pane.
    `void` | `updateUI()` Resets the UI property to a value from the current look and feel.

    - ### Methods inherited from class javax.swing.AbstractButton

      `actionPropertyChanged, addActionListener, addChangeListener, addImpl, addItemListener, checkHorizontalKey, checkVerticalKey, configurePropertiesFromAction, createActionListener, createActionPropertyChangeListener, createChangeListener, createItemListener, doClick, doClick, fireActionPerformed, fireItemStateChanged, fireStateChanged, getAction, getActionCommand, getActionListeners, getChangeListeners, getDisabledIcon, getDisabledSelectedIcon, getDisplayedMnemonicIndex, getHideActionText, getHorizontalAlignment, getHorizontalTextPosition, getIcon, getIconTextGap, getItemListeners, getLabel, getMargin, getMnemonic, getModel, getMultiClickThreshhold, getPressedIcon, getRolloverIcon, getRolloverSelectedIcon, getSelectedIcon, getSelectedObjects, getText, getUI, getVerticalAlignment, getVerticalTextPosition, imageUpdate, init, isBorderPainted, isContentAreaFilled, isFocusPainted, isRolloverEnabled, isSelected, paintBorder, removeActionListener, removeChangeListener, removeItemListener, setAction, setActionCommand, setBorderPainted, setContentAreaFilled, setDisabledIcon, setDisabledSelectedIcon, setDisplayedMnemonicIndex, setEnabled, setFocusPainted, setHideActionText, setHorizontalAlignment, setHorizontalTextPosition, setIcon, setIconTextGap, setLabel, setLayout, setMargin, setMnemonic, setMnemonic, setModel, setMultiClickThreshhold, setPressedIcon, setRolloverEnabled, setRolloverIcon, setRolloverSelectedIcon, setSelected, setSelectedIcon, setText, setUI, setVerticalAlignment, setVerticalTextPosition`

    - ### Methods inherited from class javax.swing.JComponent

      `addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update`

    - ### Methods inherited from class java.awt.Container

      `add, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, transferFocusDownCycle, validate, validateTree`

    - ### Methods inherited from class java.awt.Component

      `action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### JButton

          public JButton()

      Creates a button with no set text or icon.

    - #### JButton

          public JButton(Icon icon)

      Creates a button with an icon.
      Parameters:
        `icon` - the Icon image to display on the button

    - #### JButton

          @ConstructorProperties(value="text")
          public JButton(String text)

      Creates a button with text.
      Parameters:
        `text` - the text of the button

    - #### JButton

          public JButton(Action a)

      Creates a button where properties are taken from the `Action` supplied.
      Parameters:
        `a` - the `Action` used to specify the new button
      Since:
        1.3

    - #### JButton

          public JButton(String text,
                         Icon icon)

      Creates a button with initial text and an icon.
      Parameters:
        `text` - the text of the button
        `icon` - the Icon image to display on the button

  - ### Method Detail

    - #### updateUI

          public void updateUI()

      Resets the UI property to a value from the current look and feel.
      Overrides:
        `updateUI` in class `AbstractButton`
      See Also:
        `JComponent.updateUI()`

    - #### getUIClassID

          public String getUIClassID()

      Returns a string that specifies the name of the L&F class that renders this component.
      Overrides:
        `getUIClassID` in class `JComponent`
      Returns:
        the string "ButtonUI"
      See Also:
        `JComponent.getUIClassID()`, `UIDefaults.getUI(javax.swing.JComponent)`

    - #### isDefaultButton

          public boolean isDefaultButton()

      Gets the value of the `defaultButton` property, which if `true` means that this button is the current default button for its `JRootPane`. Most look and feels render the default button differently, and may potentially provide bindings to access the default button.
      Returns:
        the value of the `defaultButton` property
      See Also:
        `JRootPane.setDefaultButton(javax.swing.JButton)`, `isDefaultCapable()`

    - #### isDefaultCapable

          public boolean isDefaultCapable()

      Gets the value of the `defaultCapable` property.
      Returns:
        the value of the `defaultCapable` property
      See Also:
        `setDefaultCapable(boolean)`, `isDefaultButton()`, `JRootPane.setDefaultButton(javax.swing.JButton)`

    - #### setDefaultCapable

          public void setDefaultCapable(boolean defaultCapable)

      Sets the `defaultCapable` property, which determines whether this button can be made the default button for its root pane. The default value of the `defaultCapable` property is `true` unless otherwise specified by the look and feel.
      Parameters:
        `defaultCapable` - `true` if this button will be capable of being the default button on the `RootPane`; otherwise `false`
      See Also:
        `isDefaultCapable()`

    - #### removeNotify

          public void removeNotify()

      Overrides `JComponent.removeNotify` to check if this button is currently set as the default button on the `RootPane`, and if so, sets the `RootPane`'s default button to `null` to ensure the `RootPane` doesn't hold onto an invalid button reference.
      Overrides:
        `removeNotify` in class `AbstractButton`
      See Also:
        `JComponent.registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)`

    - #### paramString

          protected String paramString()

      Returns a string representation of this `JButton`. 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 `AbstractButton`
      Returns:
        a string representation of this `JButton`

    - #### getAccessibleContext

          public AccessibleContext getAccessibleContext()

      Gets the `AccessibleContext` associated with this `JButton`. For `JButton`s, the `AccessibleContext` takes the form of an `AccessibleJButton`. A new `AccessibleJButton` instance is created if necessary.
      Specified by:
        `getAccessibleContext` in interface `Accessible`
      Overrides:
        `getAccessibleContext` in class `Component`
      Returns:
        an `AccessibleJButton` that serves as the `AccessibleContext` of this `JButton`

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