Class ActionEvent
- All Implemented Interfaces:
Serializable
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".
An unspecified behavior will be caused if the id
parameter
of any particular ActionEvent
instance is not
in the range from ACTION_FIRST
to ACTION_LAST
.
- Since:
- 1.1
- See Also:
-
Field Summary
Modifier and TypeFieldDescriptionstatic final int
The first number in the range of ids used for action events.static final int
The last number in the range of ids used for action events.static final int
This event id indicates that a meaningful action occurred.static final int
The alt modifier.static final int
The control modifier.static final int
The meta modifier.static final int
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
ConstructorDescriptionActionEvent
(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
Modifier and TypeMethodDescriptionReturns the command string associated with this action.int
Returns the modifier keys held down during this action event.long
getWhen()
Returns the timestamp of when this event occurred.Returns a parameter string identifying this action event.Methods inherited from class java.util.EventObject
getSource
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Field Details
-
SHIFT_MASK
public static final int SHIFT_MASKThe shift modifier. An indicator that the shift key was held down during the event.- See Also:
-
CTRL_MASK
public static final int CTRL_MASKThe control modifier. An indicator that the control key was held down during the event.- See Also:
-
META_MASK
public static final int META_MASKThe meta modifier. An indicator that the meta key was held down during the event.- See Also:
-
ALT_MASK
public static final int ALT_MASKThe alt modifier. An indicator that the alt key was held down during the event.- See Also:
-
ACTION_FIRST
public static final int ACTION_FIRSTThe first number in the range of ids used for action events.- See Also:
-
ACTION_LAST
public static final int ACTION_LASTThe last number in the range of ids used for action events.- See Also:
-
ACTION_PERFORMED
This event id indicates that a meaningful action occurred.- See Also:
-
-
Constructor Details
-
ActionEvent
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 eventid
- 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:
-
ActionEvent
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 eventid
- 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 eventmodifiers
- 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:
-
ActionEvent
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 eventid
- 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 eventwhen
- A long that gives the time the event occurred. Passing negative or zero value is not recommendedmodifiers
- 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- Since:
- 1.4
- See Also:
-
-
Method Details
-
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
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
-