Class ComponentEvent
- java.lang.Object
-
- java.util.EventObject
-
- java.awt.AWTEvent
-
- java.awt.event.ComponentEvent
- All Implemented Interfaces:
Serializable
- Direct Known Subclasses:
-
ContainerEvent
,FocusEvent
,InputEvent
,PaintEvent
,WindowEvent
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
.
- Since:
- 1.1
- See Also:
-
ComponentAdapter
,ComponentListener
, Tutorial: Writing a Component Listener, Serialized Form
Field Summary
Modifier and Type | Field | Description |
---|---|---|
static int | COMPONENT_FIRST | The first number in the range of ids used for component events. |
static int | COMPONENT_HIDDEN | This event indicates that the component was rendered invisible. |
static int | COMPONENT_LAST | The last number in the range of ids used for component events. |
static int | COMPONENT_MOVED | This event indicates that the component's position changed. |
static int | COMPONENT_RESIZED | This event indicates that the component's size changed. |
static int | COMPONENT_SHOWN | This event indicates that the component was made visible. |
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 |
---|---|
ComponentEvent(Component source,
int id) | Constructs a |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
Component | getComponent() | Returns the originator of the event. |
String | paramString() | Returns a parameter string identifying this event. |
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
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.
- See Also:
- 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
Constructor Detail
ComponentEvent
public ComponentEvent(Component source, int id)
Constructs a ComponentEvent
object.
This method throws an IllegalArgumentException
if source
is null
.
- Parameters:
-
source
- TheComponent
that originated the event -
id
- An integer indicating the type of event. For information on allowable values, see the class description forComponentEvent
- Throws:
-
IllegalArgumentException
- ifsource
is null - See Also:
-
getComponent()
,AWTEvent.getID()
Method Detail
getComponent
public Component getComponent()
Returns the originator of the event.
- Returns:
- the
Component
object that originated the event, ornull
if the object is not aComponent
.
paramString
public String paramString()
Returns a parameter string identifying this event. This method is useful for event-logging and for debugging.
- Overrides:
-
paramString
in classAWTEvent
- Returns:
- a string identifying the event and its attributes