public class ContainerEvent extends ComponentEvent
A low-level event which indicates that a container's contents changed because a component was added or removed.
Container events are provided for notification purposes ONLY; The AWT will automatically handle changes to the containers contents internally so that the program works properly regardless of whether the program is receiving these events or not.
This low-level event is generated by a container object (such as a Panel) when a component is added to it or removed from it. The event is passed to every ContainerListener
or ContainerAdapter
object which registered to receive such events using the component's addContainerListener
method. (ContainerAdapter
objects implement the ContainerListener
interface.) Each such listener object gets this ContainerEvent
when the event occurs.
An unspecified behavior will be caused if the id
parameter of any particular ContainerEvent
instance is not in the range from CONTAINER_FIRST
to CONTAINER_LAST
.
ContainerAdapter
, ContainerListener
, Tutorial: Writing a Container Listener, Serialized Formpublic static final int CONTAINER_FIRST
The first number in the range of ids used for container events.
public static final int CONTAINER_LAST
The last number in the range of ids used for container events.
public static final int COMPONENT_ADDED
This event indicates that a component was added to the container.
public static final int COMPONENT_REMOVED
This event indicates that a component was removed from the container.
public ContainerEvent(Component source, int id, Component child)
Constructs a ContainerEvent
object.
This method throws an IllegalArgumentException
if source
is null
.
source
- The Component
object (container) that originated the eventid
- An integer indicating the type of event. For information on allowable values, see the class description for ContainerEvent
child
- the component that was added or removedIllegalArgumentException
- if source
is nullgetContainer()
, AWTEvent.getID()
, getChild()
public Container getContainer()
Returns the originator of the event.
Container
object that originated the event, or null
if the object is not a Container
.public Component getChild()
Returns the component that was affected by the event.
public String paramString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.
paramString
in class ComponentEvent
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