Class ContainerEvent
- java.lang.Object
-
- java.util.EventObject
-
- java.awt.AWTEvent
-
- java.awt.event.ComponentEvent
-
- java.awt.event.ContainerEvent
- All Implemented Interfaces:
Serializable
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
.
- Since:
- 1.1
- See Also:
-
ContainerAdapter
,ContainerListener
, Tutorial: Writing a Container Listener, Serialized Form
Field Summary
Modifier and Type | Field | Description |
---|---|---|
static int | COMPONENT_ADDED | This event indicates that a component was added to the container. |
static int | COMPONENT_REMOVED | This event indicates that a component was removed from the container. |
static int | CONTAINER_FIRST | The first number in the range of ids used for container events. |
static int | CONTAINER_LAST | The last number in the range of ids used for container events. |
Fields declared in class java.awt.event.ComponentEvent
COMPONENT_FIRST, COMPONENT_HIDDEN, COMPONENT_LAST, COMPONENT_MOVED, COMPONENT_RESIZED, COMPONENT_SHOWN
Fields declared in class java.awt.AWTEvent
ACTION_EVENT_MASK, ADJUSTMENT_EVENT_MASK, COMPONENT_EVENT_MASK, consumed, CONTAINER_EVENT_MASK, FOCUS_EVENT_MASK, HIERARCHY_BOUNDS_EVENT_MASK, HIERARCHY_EVENT_MASK, id, INPUT_METHOD_EVENT_MASK, INVOCATION_EVENT_MASK, ITEM_EVENT_MASK, KEY_EVENT_MASK, MOUSE_EVENT_MASK, MOUSE_MOTION_EVENT_MASK, MOUSE_WHEEL_EVENT_MASK, PAINT_EVENT_MASK, RESERVED_ID_MAX, TEXT_EVENT_MASK, WINDOW_EVENT_MASK, WINDOW_FOCUS_EVENT_MASK, WINDOW_STATE_EVENT_MASK
Fields declared in class java.util.EventObject
source
Constructor Summary
Constructor | Description |
---|---|
ContainerEvent(Component source,
int id,
Component child) | Constructs a |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
Component | getChild() | Returns the component that was affected by the event. |
Container | getContainer() | Returns the originator of the event. |
String | paramString() | Returns a parameter string identifying this event. |
Methods declared in class java.awt.event.ComponentEvent
getComponent
Methods declared in class java.awt.AWTEvent
consume, getID, isConsumed, setSource, toString
Methods declared in class java.util.EventObject
getSource
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Field Detail
CONTAINER_FIRST
public static final int CONTAINER_FIRST
The first number in the range of ids used for container events.
- See Also:
- Constant Field Values
CONTAINER_LAST
public static final int CONTAINER_LAST
The last number in the range of ids used for container events.
- See Also:
- Constant Field Values
COMPONENT_ADDED
public static final int COMPONENT_ADDED
This event indicates that a component was added to the container.
- See Also:
- Constant Field Values
COMPONENT_REMOVED
public static final int COMPONENT_REMOVED
This event indicates that a component was removed from the container.
- See Also:
- Constant Field Values
Constructor Detail
ContainerEvent
public ContainerEvent(Component source, int id, Component child)
Constructs a ContainerEvent
object.
This method throws an IllegalArgumentException
if source
is null
.
- Parameters:
-
source
- TheComponent
object (container) that originated the event -
id
- An integer indicating the type of event. For information on allowable values, see the class description forContainerEvent
-
child
- the component that was added or removed - Throws:
-
IllegalArgumentException
- ifsource
is null - See Also:
-
getContainer()
,AWTEvent.getID()
,getChild()
Method Detail
getContainer
public Container getContainer()
Returns the originator of the event.
- Returns:
- the
Container
object that originated the event, ornull
if the object is not aContainer
.
getChild
public Component getChild()
Returns the component that was affected by the event.
- Returns:
- the Component object that was added or removed
paramString
public String paramString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.
- Overrides:
-
paramString
in classComponentEvent
- Returns:
- a string identifying the event and its attributes