Class ActionEvent
- java.lang.Object
-
- java.util.EventObject
-
- java.awt.AWTEvent
-
- java.awt.event.ActionEvent
-
- All Implemented Interfaces:
- Serializable
public class ActionEvent extends AWTEvent
A semantic event which indicates that a component-defined action occurred. This high-level event is generated by a component (such as aButton
) when the component-specific action occurs (such as being pressed). The event is passed to everyActionListener
object that registered to receive such events using the component'saddActionListener
method.Note: To invoke an
ActionEvent
on aButton
using the keyboard, use the Space bar.The object that implements the
ActionListener
interface gets thisActionEvent
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".An unspecified behavior will be caused if the
id
parameter of any particularActionEvent
instance is not in the range fromACTION_FIRST
toACTION_LAST
.- Since:
- 1.1
- See Also:
-
ActionListener
, Tutorial: How to Write an Action Listener, Serialized Form
-
-
Field Summary
Fields Modifier and Type Field and Description static int
ACTION_FIRST
The first number in the range of ids used for action events.static int
ACTION_LAST
The last number in the range of ids used for action events.static int
ACTION_PERFORMED
This event id indicates that a meaningful action occurred.static int
ALT_MASK
The alt modifier.static int
CTRL_MASK
The control modifier.static int
META_MASK
The meta modifier.static int
SHIFT_MASK
The shift modifier.-
Fields inherited from class java.awt.AWTEvent
ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, HIERARCHY_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, WINDOW_STATE_EVENT_MASK
-
Fields inherited from class java.util.EventObject
source
-
-
Constructor Summary
Constructors Constructor and Description ActionEvent(Object source, int id, String command)
Constructs anActionEvent
object.ActionEvent(Object source, int id, String command, int modifiers)
Constructs anActionEvent
object with modifier keys.ActionEvent(Object source, int id, String command, long when, int modifiers)
Constructs anActionEvent
object with the specified modifier keys and timestamp.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description 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.-
Methods inherited from class java.util.EventObject
getSource
-
-
-
-
Field Detail
SHIFT_MASK
public static final int SHIFT_MASK
The shift modifier. An indicator that the shift key was held down during the event.- See Also:
- Constant Field Values
CTRL_MASK
public static final int CTRL_MASK
The control modifier. An indicator that the control key was held down during the event.- See Also:
- Constant Field Values
META_MASK
public static final int META_MASK
The meta modifier. An indicator that the meta key was held down during the event.- See Also:
- Constant Field Values
ALT_MASK
public static final int ALT_MASK
The alt modifier. An indicator that the alt key was held down during the event.- See Also:
- Constant Field Values
ACTION_FIRST
public static final int ACTION_FIRST
The first number in the range of ids used for action events.- See Also:
- Constant Field Values
ACTION_LAST
public static final int ACTION_LAST
The last number in the range of ids used for action events.- See Also:
- Constant Field Values
ACTION_PERFORMED
@Native public static final int ACTION_PERFORMED
This event id indicates that a meaningful action occurred.- See Also:
- Constant Field Values
-
Constructor Detail
ActionEvent
public ActionEvent(Object source, int id, String command)
Constructs anActionEvent
object.This method throws an
IllegalArgumentException
ifsource
isnull
. Anull
command
string is legal, but not recommended.- Parameters:
-
source
- The object that originated the event -
id
- An integer that identifies the event. For information on allowable values, see the class description forActionEvent
-
command
- A string that may specify a command (possibly one of several) associated with the event - Throws:
-
IllegalArgumentException
- ifsource
is null - See Also:
-
EventObject.getSource()
,AWTEvent.getID()
,getActionCommand()
ActionEvent
public ActionEvent(Object source, int id, String command, int modifiers)
Constructs anActionEvent
object with modifier keys.This method throws an
IllegalArgumentException
ifsource
isnull
. Anull
command
string is legal, but not recommended.- Parameters:
-
source
- The object that originated the event -
id
- An integer that identifies the event. For information on allowable values, see the class description forActionEvent
-
command
- A string that may specify a command (possibly one of several) associated with the event -
modifiers
- The modifier keys down during event (shift, ctrl, alt, meta). Passing negative parameter is not recommended. Zero value means that no modifiers were passed - Throws:
-
IllegalArgumentException
- ifsource
is null - See Also:
-
EventObject.getSource()
,AWTEvent.getID()
,getActionCommand()
,getModifiers()
ActionEvent
public ActionEvent(Object source, int id, String command, long when, int modifiers)
Constructs anActionEvent
object with the specified modifier keys and timestamp.This method throws an
IllegalArgumentException
ifsource
isnull
. Anull
command
string is legal, but not recommended.- Parameters:
-
source
- The object that originated the event -
id
- An integer that identifies the event. For information on allowable values, see the class description forActionEvent
-
command
- A string that may specify a command (possibly one of several) associated with the event -
modifiers
- The modifier keys down during event (shift, ctrl, alt, meta). Passing negative parameter is not recommended. Zero value means that no modifiers were passed -
when
- A long that gives the time the event occurred. Passing negative or zero value is not recommended - Throws:
-
IllegalArgumentException
- ifsource
is null - Since:
- 1.4
- See Also:
-
EventObject.getSource()
,AWTEvent.getID()
,getActionCommand()
,getModifiers()
,getWhen()
-
Method Detail
getActionCommand
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 thisActionEvent
, this this method returnsnull
.- Returns:
- the string identifying the command for this event
getWhen
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
- Since:
- 1.4
getModifiers
public int getModifiers()
Returns the modifier keys held down during this action event.- Returns:
- the bitwise-or of the modifier constants
paramString
public String paramString()
Returns a parameter string identifying this action event. This method is useful for event-logging and for debugging.- Overrides:
-
paramString
in classAWTEvent
- Returns:
- a string identifying the event and its associated command
-
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