FileDocCategorySizeDatePackage
JButton.javaAPI DocJava SE 6 API9894Tue Jun 10 00:26:36 BST 2008javax.swing

JButton

public class JButton extends AbstractButton implements Accessible
An implementation of a "push" button.

Buttons can be configured, and to some degree controlled, by Actions. 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 JavaBeansTM has been added to the java.beans package. Please see {@link java.beans.XMLEncoder}.

beaninfo
attribute: isContainer false description: An implementation of a \"push\" button.
version
1.100 08/08/06
author
Jeff Dinkins

Fields Summary
private static final String
uiClassID
Constructors Summary
public JButton()
Creates a button with no set text or icon.


                  
      
        this(null, null);
    
public JButton(Icon icon)
Creates a button with an icon.

param
icon the Icon image to display on the button

        this(null, icon);
    
public JButton(String text)
Creates a button with text.

param
text the text of the button

        this(text, null);
    
public JButton(Action a)
Creates a button where properties are taken from the Action supplied.

param
a the Action used to specify the new button
since
1.3

        this();
	setAction(a);
    
public JButton(String text, Icon icon)
Creates a button with initial text and an icon.

param
text the text of the button
param
icon the Icon image to display on the button

        // Create the model
        setModel(new DefaultButtonModel());

        // initialize
        init(text, icon);
    
Methods Summary
public javax.accessibility.AccessibleContextgetAccessibleContext()
Gets the AccessibleContext associated with this JButton. For JButtons, the AccessibleContext takes the form of an AccessibleJButton. A new AccessibleJButton instance is created if necessary.

return
an AccessibleJButton that serves as the AccessibleContext of this JButton
beaninfo
expert: true description: The AccessibleContext associated with this Button.

        if (accessibleContext == null) {
            accessibleContext = new AccessibleJButton();
        }
        return accessibleContext;
    
public java.lang.StringgetUIClassID()
Returns a string that specifies the name of the L&F class that renders this component.

return
the string "ButtonUI"
see
JComponent#getUIClassID
see
UIDefaults#getUI
beaninfo
expert: true description: A string that specifies the name of the L&F class.

        return uiClassID;
    
public booleanisDefaultButton()
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.

return
the value of the defaultButton property
see
JRootPane#setDefaultButton
see
#isDefaultCapable
beaninfo
description: Whether or not this button is the default button

        JRootPane root = SwingUtilities.getRootPane(this);
        if (root != null) {
            return root.getDefaultButton() == this;
        }
        return false;
    
public booleanisDefaultCapable()
Gets the value of the defaultCapable property.

return
the value of the defaultCapable property
see
#setDefaultCapable
see
#isDefaultButton
see
JRootPane#setDefaultButton

        return defaultCapable;
    
protected java.lang.StringparamString()
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.

return
a string representation of this JButton

	String defaultCapableString = (defaultCapable ? "true" : "false");
	
	return super.paramString() +
	    ",defaultCapable=" + defaultCapableString;
    
public voidremoveNotify()
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.

        JRootPane root = SwingUtilities.getRootPane(this);
        if (root != null && root.getDefaultButton() == this) {
            root.setDefaultButton(null);
        }
        super.removeNotify();
    
public voidsetDefaultCapable(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.

param
defaultCapable true if this button will be capable of being the default button on the RootPane; otherwise false
see
#isDefaultCapable
beaninfo
bound: true attribute: visualUpdate true description: Whether or not this button can be the default button

        boolean oldDefaultCapable = this.defaultCapable;
        this.defaultCapable = defaultCapable;
        firePropertyChange("defaultCapable", oldDefaultCapable, defaultCapable);
    
public voidupdateUI()
Resets the UI property to a value from the current look and feel.

see
JComponent#updateUI

        setUI((ButtonUI)UIManager.getUI(this));
    
private voidwriteObject(java.io.ObjectOutputStream s)
See readObject() and writeObject() in JComponent for more information about serialization in Swing.

        s.defaultWriteObject();
        if (getUIClassID().equals(uiClassID)) {
            byte count = JComponent.getWriteObjCounter(this);
            JComponent.setWriteObjCounter(this, --count);
            if (count == 0 && ui != null) {
                ui.installUI(this);
            }
        }