To listen for the events dispatched by a
window, register a listener with the window instance. For example,
to listen for the closing event, register a listener with the window
as follows:
myWindow.addEventListener(Event.CLOSING, onClosingEvent);
When an event is dispatched, the
target
property
references the window sending the event.
Most window events have two related messages. The first message
signals that a window change is imminent (and can be canceled),
while the second message signals that the change has occurred. For
example, when a user clicks the close button of a window, the closing
event message is dispatched. If no listeners cancel the event, the
window closes and the close event is dispatched to any listeners.
Typically, the warning events, such as
closing
,
are only dispatched when system chrome has been used to trigger
an event. Calling the window
close()
method, for
example, does not automatically dispatch the
closing
event—only
the
close
event is dispatched. You can, however,
construct a closing event object and dispatch it using the window
dispatchEvent()
method.
The window events that dispatch an Event object
are:
|
Event
|
Description
|
|
activate
|
Dispatched when the window receives focus.
|
|
deactivate
|
Dispatched when the window loses focus
|
|
closing
|
Dispatched when the window is about to close.
This only occurs automatically when the system chrome close button
is pressed or, on Mac OS X, when the Quit command is invoked.
|
|
close
|
Dispatched when the window has closed.
|
The
window events that dispatch an NativeWindowBoundsEvent object are:
|
Event
|
Description
|
|
moving
|
Dispatched immediately before the top-left
corner of the window changes position, either as a result of moving, resizing
or changing the window display state.
|
|
move
|
Dispatched after the top-left corner has
changed position.
|
|
resizing
|
Dispatched immediately before the window
width or height changes either as a result of resizing or a display state
change.
|
|
resize
|
Dispatched after the window has changed
size.
|
For NativeWindowBoundsEvent events, you can use the
beforeBounds
and
afterBounds
properties
to determine the window bounds before and after the impending or
completed change.
The window events that dispatch an NativeWindowDisplayStateEvent
object are:
|
Event
|
Description
|
|
displayStateChanging
|
Dispatched immediately before the window
display state changes.
|
|
displayStateChange
|
Dispatched after the window display state
has changed.
|
For NativeWindowDisplayStateEvent events, you can use the
beforeDisplayState
and
afterDisplayState
properties
to determine the window display state before and after the impending
or completed change.
On some Linux window managers, a display state change event is
not dispatched when a window with a maximum size setting is maximized.
(The window is set to the maximized display state, but is not resized.)
