ActionEvent

ActionEvent is a type of event in Java's AWT/Swing event model that signals a user action on a component, such as pressing a button, selecting a menu item, or pressing Enter in a text field. It is generated by components capable of triggering actions, including JButton, JMenuItem, and other AbstractButton descendants, as well as certain text components.

An ActionEvent is delivered to listeners that implement the ActionListener interface (java.awt.event.ActionListener). The listener method actionPerformed(ActionEvent e) is invoked when the event occurs. The event carries information: the source object (the component that fired the event), an action command string identifying the action (obtainable via getActionCommand()), and a timestamp indicating when the action happened. The event’s id is typically ActionEvent.ACTION_PERFORMED.

Typical usage involves registering a listener with addActionListener on the component. If multiple controls share a single listener, the action command can distinguish them via setActionCommand. In Swing, the same concept can be encapsulated using the Action interface or AbstractAction, enabling actions to be attached to multiple components consistently. JavaFX offers a similar construct with javafx.event.ActionEvent and EventHandler<ActionEvent>.

ActionEvent forms part of the broader event-handling model in Java GUI programming and is used for discrete user actions that have a direct trigger, such as a button press, making it a common element in interactive applications. See also ActionListener, AbstractAction, JButton, JMenuItem, and javafx.event.ActionEvent for related concepts in Java GUI development.