Module java.desktop
Package java.awt.event

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 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".

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 Details

    • 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:

    • 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:

    • 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:

    • 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:

    • ACTION_FIRST

      public static final int ACTION_FIRST
      The first number in the range of ids used for action events.
      See Also:

    • ACTION_LAST

      public static final int ACTION_LAST
      The last number in the range of ids used for action events.
      See Also:

    • ACTION_PERFORMED

      @Native public static final int ACTION_PERFORMED
      This event id indicates that a meaningful action occurred.
      See Also:

  • Constructor Details

    • ActionEvent

      public ActionEvent(Object source, int id, String command)
      Constructs an ActionEvent object.

      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. For information on allowable values, see the class description for ActionEvent
      command - A string that may specify a command (possibly one of several) associated with the event
      Throws:
      IllegalArgumentException - if source is null
      See Also:

    • ActionEvent

      public ActionEvent(Object source, int id, String command, int modifiers)
      Constructs an ActionEvent object with modifier keys.

      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. For information on allowable values, see the class description for ActionEvent
      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 - if source is null
      See Also:

    • ActionEvent

      public ActionEvent(Object source, int id, String command, long when, int modifiers)
      Constructs an ActionEvent object with the specified modifier keys and timestamp.

      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. For information on allowable values, see the class description for ActionEvent
      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 - if source is null
      Since:
      1.4
      See Also:

  • Method Details

    • 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 this ActionEvent, this this method returns null.

      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 class AWTEvent
      Returns:
      a string identifying the event and its associated command