Class ComponentEvent

public class ComponentEvent
extends AWTEvent

A low-level event which indicates that a component moved, changed size, or changed visibility (also, the root class for the other component-level events).

Component events are provided for notification purposes ONLY; The AWT will automatically handle component moves and resizes internally so that GUI layout works properly regardless of whether a program is receiving these events or not.

In addition to serving as the base class for other component-related events (InputEvent, FocusEvent, WindowEvent, ContainerEvent), this class defines the events that indicate changes in a component's size, position, or visibility.

This low-level event is generated by a component object (such as a List) when the component is moved, resized, rendered invisible, or made visible again. The event is passed to every ComponentListener or ComponentAdapter object which registered to receive such events using the component's addComponentListener method. (ComponentAdapter objects implement the ComponentListener interface.) Each such listener object gets this ComponentEvent when the event occurs.

An unspecified behavior will be caused if the id parameter of any particular ComponentEvent instance is not in the range from COMPONENT_FIRST to COMPONENT_LAST.

Fields

COMPONENT_FIRST

public static final int COMPONENT_FIRST

The first number in the range of ids used for component events.

See Also:

Constant Field Values

COMPONENT_LAST

public static final int COMPONENT_LAST

The last number in the range of ids used for component events.

See Also:

Constant Field Values

COMPONENT_MOVED

@Native
public static final int COMPONENT_MOVED

This event indicates that the component's position changed.

See Also:

Constant Field Values

COMPONENT_RESIZED

@Native
public static final int COMPONENT_RESIZED

This event indicates that the component's size changed.

See Also:

Constant Field Values

COMPONENT_SHOWN

@Native
public static final int COMPONENT_SHOWN

This event indicates that the component was made visible.

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Constant Field Values

COMPONENT_HIDDEN

@Native
public static final int COMPONENT_HIDDEN

This event indicates that the component was rendered invisible.

See Also:

Constant Field Values

Constructors

ComponentEvent

public ComponentEvent(Component source,
                      int id)

Parameters:

source - The Component that originated the event

id - An integer indicating the type of event. For information on allowable values, see the class description for ComponentEvent

Throws:

IllegalArgumentException - if source is null

See Also:

getComponent(), AWTEvent.getID()

Methods

getComponent

public Component getComponent()

Returns the originator of the event.

Returns:

the Component object that originated the event, or null if the object is not a Component.

paramString

public String paramString()

Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.

Overrides:

paramString in class AWTEvent

Returns:

a string identifying the event and its attributes