java.lang.Object
java.util.EventObject
java.awt.AWTEvent
java.awt.event.ItemEvent
- All Implemented Interfaces:
Serializable
public class ItemEvent extends AWTEvent
A semantic event which indicates that an item was selected or deselected.
This high-level event is generated by an ItemSelectable object (such as a
List) when an item is selected or deselected by the user.
The event is passed to every
ItemListener
object which
registered to receive such events using the component's
addItemListener
method.
The object that implements the ItemListener
interface gets
this ItemEvent
when the event occurs. The listener is
spared the details of processing individual mouse movements and mouse
clicks, and can instead process a "meaningful" (semantic) event like
"item selected" or "item deselected".
An unspecified behavior will be caused if the id
parameter
of any particular ItemEvent
instance is not
in the range from ITEM_FIRST
to ITEM_LAST
.
The stateChange
of any ItemEvent
instance takes one of the following
values:
-
ItemEvent.SELECTED
-
ItemEvent.DESELECTED
- Since:
- 1.1
- See Also:
ItemSelectable
,ItemListener
, Tutorial: Writing an Item Listener, Serialized Form
-
Field Summary
Fields Modifier and Type Field Description static int
DESELECTED
This state-change-value indicates that a selected item was deselected.static int
ITEM_FIRST
The first number in the range of ids used for item events.static int
ITEM_LAST
The last number in the range of ids used for item events.static int
ITEM_STATE_CHANGED
This event id indicates that an item's state changed.static int
SELECTED
This state-change value indicates that an item was selected.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
Constructors Constructor Description ItemEvent(ItemSelectable source, int id, Object item, int stateChange)
Constructs anItemEvent
object. -
Method Summary
Modifier and Type Method Description Object
getItem()
Returns the item affected by the event.ItemSelectable
getItemSelectable()
Returns the originator of the event.int
getStateChange()
Returns the type of state change (selected or deselected).String
paramString()
Returns a parameter string identifying this item event.Methods declared in class java.util.EventObject
getSource
-
Field Details
-
ITEM_FIRST
public static final int ITEM_FIRSTThe first number in the range of ids used for item events.- See Also:
- Constant Field Values
-
ITEM_LAST
public static final int ITEM_LASTThe last number in the range of ids used for item events.- See Also:
- Constant Field Values
-
ITEM_STATE_CHANGED
public static final int ITEM_STATE_CHANGEDThis event id indicates that an item's state changed.- See Also:
- Constant Field Values
-
SELECTED
public static final int SELECTEDThis state-change value indicates that an item was selected.- See Also:
- Constant Field Values
-
DESELECTED
public static final int DESELECTEDThis state-change-value indicates that a selected item was deselected.- See Also:
- Constant Field Values
-
-
Constructor Details
-
ItemEvent
Constructs anItemEvent
object.This method throws an
IllegalArgumentException
ifsource
isnull
.- Parameters:
source
- TheItemSelectable
object that originated the eventid
- The integer that identifies the event type. For information on allowable values, see the class description forItemEvent
item
- An object -- the item affected by the eventstateChange
- An integer that indicates whether the item was selected or deselected. For information on allowable values, see the class description forItemEvent
- Throws:
IllegalArgumentException
- ifsource
is null- See Also:
getItemSelectable()
,AWTEvent.getID()
,getStateChange()
-
-
Method Details
-
getItemSelectable
Returns the originator of the event.- Returns:
- the ItemSelectable object that originated the event.
-
getItem
Returns the item affected by the event.- Returns:
- the item (object) that was affected by the event
-
getStateChange
public int getStateChange()Returns the type of state change (selected or deselected).- Returns:
- an integer that indicates whether the item was selected or deselected
- See Also:
SELECTED
,DESELECTED
-
paramString
Returns a parameter string identifying this item event. This method is useful for event-logging and for debugging.- Overrides:
paramString
in classAWTEvent
- Returns:
- a string identifying the event and its attributes
-