| FocusEvent |
|
typedict |
| |
A
FocusEvent
indicates that a component has gained or lost the keyboard focus.
The fields in a
FocusEvent
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.
| | temporary |
An
int
that is
1
when the focus change is temporary and
0
otherwise.
|
Most components can receive
FocusEvents,
but they only arrive if the component has defined
one or more of the event handlers listed below.
| |
| Event Handlers: |
focusGained,
focusLost
| | |
| Example: |
The program,
import yoix.*.*;
JFrame f = {
FlowLayout layoutmanager = {
int vgap = 72;
int hgap = 72/8;
};
Array layout = {
new JTextField {
String tag = "$_textfield";
String text = "This is a test";
int columns = 20;
focusGained(Event e) {
printf("JTextField.focusGained: %O\n", e);
}
focusLost(Event e) {
printf("JTextField.focusLost: %O\n", e);
}
},
new JButton {
String text = "Clear";
int requestfocus = TRUE;
focusGained(Event e) {
printf("JButton.focusGained: %O\n", e);
}
focusLost(Event e) {
printf("JButton.focusLost: %O\n", e);
}
actionPerformed(e) {
root.components.$_textfield.text = NULL;
}
},
};
};
f.visible = TRUE;
adds
focusGained
and
focusLost
event handlers to a
JTextField
and
JButton,
puts them both in a frame, and uses the button's
requestfocus
field ask for the focus when the frame first becomes visible.
| | |
| See Also: |
ActionEvent,
AdjustmentEvent,
CaretEvent,
ChangeEvent,
ComponentEvent,
DragGestureEvent,
DragSourceEvent,
DropTargetEvent,
Event,
HyperlinkEvent,
InvocationEvent,
invokeLater,
isDispatchThread,
ItemEvent,
KeyEvent,
ListSelectionEvent,
MouseEvent,
MouseWheelEvent,
PaintEvent,
postEvent,
TextEvent,
TreeSelectionEvent,
WindowEvent
|
|
Yoix is a registered trademark of AT&T Inc.
|
