public class

ActionEvent

extends AWTEvent
java.lang.Object
   ↳ java.util.EventObject
     ↳ java.awt.AWTEvent
       ↳ java.awt.event.ActionEvent

Class Overview

A semantic event which indicates that a component-defined action occurred. This high-level event is generated by a component (such as a Button) when the component-specific action occurs (such as being pressed). The event is passed to every ActionListener object that registered to receive such events using the component's addActionListener method.

Note: To invoke an ActionEvent on a Button using the keyboard, use the Space bar.

The object that implements the ActionListener interface gets this ActionEvent when the event occurs. The listener is therefore spared the details of processing individual mouse movements and mouse clicks, and can instead process a "meaningful" (semantic) event like "button pressed".

See Also

Summary

Constants
int ACTION_FIRST The first number in the range of ids used for action events.
int ACTION_LAST The last number in the range of ids used for action events.
int ACTION_PERFORMED This event id indicates that a meaningful action occured.
int ALT_MASK The alt modifier.
int CTRL_MASK The control modifier.
int META_MASK The meta modifier.
int SHIFT_MASK The shift modifier.
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Inherited Constants
From class java.awt.AWTEvent
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Inherited Fields
From class java.awt.AWTEvent
From class java.util.EventObject
Public Constructors
ActionEvent(Object source, int id, String command)
Constructs an ActionEvent object.
ActionEvent(Object source, int id, String command, int modifiers)
Constructs an ActionEvent object with modifier keys.
ActionEvent(Object source, int id, String command, long when, int modifiers)
Constructs an ActionEvent object with the specified modifier keys and timestamp.
Public Methods
String getActionCommand()
Returns the command string associated with this action.
int getModifiers()
Returns the modifier keys held down during this action event.
long getWhen()
Returns the timestamp of when this event occurred.
String paramString()
Returns a parameter string identifying this action event.
[Expand]
Inherited Methods
From class java.awt.AWTEvent
From class java.util.EventObject
From class java.lang.Object

Constants

public static final int ACTION_FIRST

The first number in the range of ids used for action events.

Constant Value: 1001 (0x000003e9)

public static final int ACTION_LAST

The last number in the range of ids used for action events.

Constant Value: 1001 (0x000003e9)

public static final int ACTION_PERFORMED

This event id indicates that a meaningful action occured.

Constant Value: 1001 (0x000003e9)

public static final int ALT_MASK

The alt modifier. An indicator that the alt key was held down during the event.

Constant Value: 8 (0x00000008)

public static final int CTRL_MASK

The control modifier. An indicator that the control key was held down during the event.

Constant Value: 2 (0x00000002)

public static final int META_MASK

The meta modifier. An indicator that the meta key was held down during the event.

Constant Value: 4 (0x00000004)

public static final int SHIFT_MASK

The shift modifier. An indicator that the shift key was held down during the event.

Constant Value: 1 (0x00000001)

Public Constructors

public ActionEvent (Object source, int id, String command)

Constructs an ActionEvent object.

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null. A null command string is legal, but not recommended.

Parameters
source the object that originated the event
id an integer that identifies the event
command a string that may specify a command (possibly one of several) associated with the event
Throws
IllegalArgumentException if source is null

public ActionEvent (Object source, int id, String command, int modifiers)

Constructs an ActionEvent object with modifier keys.

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null. A null command string is legal, but not recommended.

Parameters
source the object that originated the event
id an integer that identifies the event
command a string that may specify a command (possibly one of several) associated with the event
modifiers the modifier keys held down during this action
Throws
IllegalArgumentException if source is null

public ActionEvent (Object source, int id, String command, long when, int modifiers)

Constructs an ActionEvent object with the specified modifier keys and timestamp.

Note that passing in an invalid id results in unspecified behavior. This method throws an IllegalArgumentException if source is null. A null command string is legal, but not recommended.

Parameters
source the object that originated the event
id an integer that identifies the event
command a string that may specify a command (possibly one of several) associated with the event
when the time the event occurred
modifiers the modifier keys held down during this action
Throws
IllegalArgumentException if source is null

Public Methods

public String getActionCommand ()

Returns the command string associated with this action. This string allows a "modal" component to specify one of several commands, depending on its state. For example, a single button might toggle between "show details" and "hide details". The source object and the event would be the same in each case, but the command string would identify the intended action.

Note that if a null command string was passed to the constructor for this ActionEvent, this this method returns null.

Returns
  • the string identifying the command for this event

public int getModifiers ()

Returns the modifier keys held down during this action event.

Returns
  • the bitwise-or of the modifier constants

public long getWhen ()

Returns the timestamp of when this event occurred. Because an ActionEvent is a high-level, semantic event, the timestamp is typically the same as an underlying InputEvent.

Returns
  • this event's timestamp

public String paramString ()

Returns a parameter string identifying this action event. This method is useful for event-logging and for debugging.

Returns
  • a string identifying the event and its associated command