ActionEventpublic 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 a
Button) when
the component-specific action occurs (such as being pressed).
The event is passed to every 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". |
| Fields Summary |
|---|
| public static final int | SHIFT_MASKThe shift modifier. An indicator that the shift key was held
down during the event. | | public static final int | CTRL_MASKThe control modifier. An indicator that the control key was held
down during the event. | | public static final int | META_MASKThe meta modifier. An indicator that the meta key was held
down during the event. | | public static final int | ALT_MASKThe alt modifier. An indicator that the alt key was held
down during the event. | | public static final int | ACTION_FIRSTThe first number in the range of ids used for action events. | | public static final int | ACTION_LASTThe last number in the range of ids used for action events. | | public static final int | ACTION_PERFORMEDThis event id indicates that a meaningful action occured. | | String | actionCommandThe nonlocalized string that gives more details
of what actually caused the event.
This information is very specific to the component
that fired it. | | long | whenTimestamp of when this event occurred. Because an ActionEvent is a high-
level, semantic event, the timestamp is typically the same as an
underlying InputEvent. | | int | modifiersThis represents the key modifier that was selected,
and is used to determine the state of the selected key.
If no modifier has been selected it will default to
zero. | | private static final long | serialVersionUID |
| Constructors Summary |
|---|
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.
this(source, id, command, 0);
| 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.
this(source, id, command, 0, modifiers);
| 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.
super(source, id);
this.actionCommand = command;
this.when = when;
this.modifiers = modifiers;
|
| Methods Summary |
|---|
| public java.lang.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.
return actionCommand;
| | public int | getModifiers()Returns the modifier keys held down during this action event.
return modifiers;
| | 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.
return when;
| | public java.lang.String | paramString()Returns a parameter string identifying this action event.
This method is useful for event-logging and for debugging.
String typeStr;
switch(id) {
case ACTION_PERFORMED:
typeStr = "ACTION_PERFORMED";
break;
default:
typeStr = "unknown type";
}
return typeStr + ",cmd="+actionCommand+",when="+when+",modifiers="+
KeyEvent.getKeyModifiersText(modifiers);
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