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Chapter 19 java.awt Reference |
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Button
Name
Button
![[Graphic: Figure from the text]](./figs/button.gif)
Description
The Button is the familiar labeled button object. It inherits most of its functionality from Component. For example, to change the font of the Button, you would use Component's setFont() method. The Button sends java.awt.event.ActionEvent objects to its listeners when it is pressed.
Class Definition
public class java.awt.Button
extends java.awt.Component {
// Constructors
public Button();
public Button (String label);
// Instance Methods
public void addActionListener (ActionListener l); 
public void addNotify();
public String getActionCommand();
public String getLabel();
public void removeActionListener (ActionListener l);
public void setActionCommand (String command);
public synchronized void setLabel (String label);
// Protected Instance Methods
protected String paramString();
protected void processActionEvent (ActionEvent e);
protected void processEvent (AWTEvent e);
}
Constructors
Button
public Button()
- Description
-
Constructs a Button object with no label.
public Button (String label)
- Parameters
-
- label
-
The text for the label on the button
- label
- Description
-
Constructs a Button object with text of label.
Instance Methods
addActionListener
public void addActionListener (ActionListener l)
- Parameters
-
- l
-
An object that implements the ActionListener interface.
- l
- Description
-
Add a listener for the action event.
addNotify
public void addNotify()
- Overrides
-
Component.addNotify()
- Description
-
Creates Button's peer.
getActionCommand
public String getActionCommand()
- Returns
-
Current action command string.
- Description
-
Returns the string used for the action command.
getLabel
public String getLabel()
- Returns
-
Text of the Button's label.
removeActionListener
public void removeActionListener (ActionListener l)
- Parameters
-
- l
-
One of this Button's ActionListeners.
- l
- Description
-
Remove an action event listener.
setActionCommand
public void setActionCommand (String command)
- Parameters
-
- command
-
New action command string.
- command
- Description
-
Specify the string used for the action command.
setLabel
public synchronized void setLabel (String label)
- Parameters
-
- label
-
New text for label of Button.
- label
- Description
-
Changes the Button's label to label.
Protected Instance Methods
paramString
protected String paramString()
- Returns
-
String with current settings of Button.
- Overrides
-
Component.paramString()
- Description
-
Helper method for toString() used to generate a string of current settings.
processActionEvent
protected void processActionEvent (ActionEvent e)
- Parameters
-
- e
-
The action event to process.
- e
- Description
-
Action events are passed to this method for processing. Normally, this method is called by processEvent().
processEvent
protected void processEvent (AWTEvent e)
- Parameters
-
- e
-
The event to process.
- e
- Description
-
Low level AWTEvents are passed to this method for processing.
See Also
ActionListener, Component, String
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| BorderLayout |  |
Canvas |
