ComponentListener

ComponentListener is an interface in Java's Abstract Window Toolkit (AWT) and Swing libraries. It is used to receive component events, which are notifications of changes to a component's state. These events include when a component is added to a container, removed from a container, resized, or moved.

To use ComponentListener, you must implement its methods in a class. The interface defines four methods: componentResized, componentMoved, componentShown, and componentHidden. When a component event occurs, the corresponding method in the listener is invoked. For example, if a window is resized, the componentResized method would be called.

ComponentListener is part of the event-handling mechanism in Java GUI programming. It allows developers to respond dynamically to changes in the layout and visibility of graphical components. This is useful for tasks such as updating the display of other components based on size changes, repositioning elements when a window is moved, or performing actions when a component becomes visible or invisible.

To associate a ComponentListener with a component, you use the addComponentListener method of the component. This method takes an instance of a class that implements the ComponentListener interface as an argument. The component then dispatches events to this listener as they occur. For simpler use cases, the ComponentAdapter class provides a convenient default implementation of all ComponentListener methods, allowing you to override only the methods you need.