| ItemEvent |
|
typedict |
| |
An
ItemEvent
indicates that an item in a component, like a
JComboBox
or
Choice
has undergone
a state change because it was either selected or deselected.
Components that display popup menus or menubars can also get
ItemEvents
from their menus.
The fields in an
ItemEvent
are:
| id |
An
Object
that must be an
int
or
String,
that identifies the type of this event.
A value that is a
String
must be the name of an event handler that can process this event.
A value that is an
int
must be a number that the
yoix.event.HandlerID
dictionary associates with an event handler that can process this event.
In practice,
id
is only used when you build an event that gets handed to
postEvent,
and in that case the value assigned to
id
is almost always a
String.
| | item |
An
Object
that represents the item that was selected by the event.
In practice, most itemStateChanged event handlers do their job without
ever looking at
item.
| | state |
An
int
that is
1
when the item was selected, and
0
otherwise.
|
Components like
JButton,
JComboBox,
Checkbox,
Choice,
and
List
can receive
ItemEvents,
but they only arrive if the component has defined an
itemStateChanged
event handler.
In addition, any component that displays a popup menu or menubar can get
ItemEvents
from those menus if they have an
itemStateChanged
event handler.
| |
| Event Handlers: |
itemStateChanged
| | |
| Example: |
The program,
import yoix.*.*;
VM.exitmodel = 0; // so main thread does not exit
JComboBox checkbox = {
itemStateChanged(Event e) {
printf("Received: %O\n", e);
exit(0);
}
};
ItemEvent event = {
String id = "itemStateChanged";
String item = "A fake event";
int state = 1;
};
printf("Posting: %O\n", event);
postEvent(event, checkbox);
prints
Posting: Event[3:0]
id=^"itemStateChanged"
item=^"A fake event"
>state=1
Received: Event[3:0]
id=701
item=^"A fake event"
>state=1
on standard output.
Notice how the
id
field changed from a string to the corresponding integer by the time
itemStateChanged
got the event.
| | |
| See Also: |
ActionEvent,
AdjustmentEvent,
CaretEvent,
ChangeEvent,
ComponentEvent,
DragGestureEvent,
DragSourceEvent,
DropTargetEvent,
Event,
FocusEvent,
HyperlinkEvent,
InvocationEvent,
invokeLater,
isDispatchThread,
KeyEvent,
ListSelectionEvent,
MouseEvent,
MouseWheelEvent,
PaintEvent,
postEvent,
TextEvent,
TreeSelectionEvent,
WindowEvent
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Yoix is a registered trademark of AT&T Inc.
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