wxUpdateUIEvent - Functions for wxUpdateUIEvent class
Please see following description for synopsis
wxUpdateUIEvent(3) Erlang Module Definition wxUpdateUIEvent(3)
NAME
wxUpdateUIEvent - Functions for wxUpdateUIEvent class
DESCRIPTION
This class is used for pseudo-events which are called by wxWidgets to
give an application the chance to update various user interface ele-
ments.
Without update UI events, an application has to work hard to
check/uncheck, enable/disable, show/hide, and set the text for elements
such as menu items and toolbar buttons. The code for doing this has to
be mixed up with the code that is invoked when an action is invoked for
a menu item or button.
With update UI events, you define an event handler to look at the state
of the application and change UI elements accordingly. wxWidgets will
call your member functions in idle time, so you don't have to worry
where to call this code.
In addition to being a clearer and more declarative method, it also
means you don't have to worry whether you're updating a toolbar or
menubar identifier. The same handler can update a menu item and toolbar
button, if the identifier is the same. Instead of directly manipulating
the menu or button, you call functions in the event object, such as
check/2. wxWidgets will determine whether such a call has been made,
and which UI element to update.
These events will work for popup menus as well as menubars. Just before
a menu is popped up, wxMenu::UpdateUI (not implemented in wx) is called
to process any UI events for the window that owns the menu.
If you find that the overhead of UI update processing is affecting your
application, you can do one or both of the following:
Note that although events are sent in idle time, defining a wxIdleEvent
handler for a window does not affect this because the events are sent
from wxWindow::OnInternalIdle (not implemented in wx) which is always
called in idle time.
wxWidgets tries to optimize update events on some platforms. On Windows
and GTK+, events for menubar items are only sent when the menu is about
to be shown, and not in idle time.
See: Overview events
This class is derived (and can use functions) from: wxCommandEvent
wxEvent
wxWidgets docs: wxUpdateUIEvent
EVENTS
Use wxEvtHandler:connect/3 with wxUpdateUIEventType to subscribe to
events of this type.
DATA TYPES
wxUpdateUIEvent() = wx:wx_object()
wxUpdateUI() =
#wxUpdateUI{type = wxUpdateUIEvent:wxUpdateUIEventType()}
wxUpdateUIEventType() = update_ui
EXPORTS
canUpdate(Window) -> boolean()
Types:
Window = wxWindow:wxWindow()
Returns true if it is appropriate to update (send UI update
events to) this window.
This function looks at the mode used (see setMode/1), the
wxWS_EX_PROCESS_UI_UPDATES flag in window, the time update
events were last sent in idle time, and the update interval, to
determine whether events should be sent to this window now. By
default this will always return true because the update mode is
initially wxUPDATE_UI_PROCESS_ALL and the interval is set to 0;
so update events will be sent as often as possible. You can
reduce the frequency that events are sent by changing the mode
and/or setting an update interval.
See: resetUpdateTime/0, setUpdateInterval/1, setMode/1
check(This, Check) -> ok
Types:
This = wxUpdateUIEvent()
Check = boolean()
Check or uncheck the UI element.
enable(This, Enable) -> ok
Types:
This = wxUpdateUIEvent()
Enable = boolean()
Enable or disable the UI element.
show(This, Show) -> ok
Types:
This = wxUpdateUIEvent()
Show = boolean()
Show or hide the UI element.
getChecked(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the UI element should be checked.
getEnabled(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the UI element should be enabled.
getShown(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the UI element should be shown.
getSetChecked(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the application has called check/2.
For wxWidgets internal use only.
getSetEnabled(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the application has called enable/2.
For wxWidgets internal use only.
getSetShown(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the application has called show/2.
For wxWidgets internal use only.
getSetText(This) -> boolean()
Types:
This = wxUpdateUIEvent()
Returns true if the application has called setText/2.
For wxWidgets internal use only.
getText(This) -> unicode:charlist()
Types:
This = wxUpdateUIEvent()
Returns the text that should be set for the UI element.
getMode() -> wx:wx_enum()
Static function returning a value specifying how wxWidgets will
send update events: to all windows, or only to those which spec-
ify that they will process the events.
See: setMode/1
getUpdateInterval() -> integer()
Returns the current interval between updates in milliseconds.
The value -1 disables updates, 0 updates as frequently as possi-
ble.
See: setUpdateInterval/1
resetUpdateTime() -> ok
Used internally to reset the last-updated time to the current
time.
It is assumed that update events are normally sent in idle time,
so this is called at the end of idle processing.
See: canUpdate/1, setUpdateInterval/1, setMode/1
setMode(Mode) -> ok
Types:
Mode = wx:wx_enum()
Specify how wxWidgets will send update events: to all windows,
or only to those which specify that they will process the
events.
setText(This, Text) -> ok
Types:
This = wxUpdateUIEvent()
Text = unicode:chardata()
Sets the text for this UI element.
setUpdateInterval(UpdateInterval) -> ok
Types:
UpdateInterval = integer()
Sets the interval between updates in milliseconds.
Set to -1 to disable updates, or to 0 to update as frequently as
possible. The default is 0.
Use this to reduce the overhead of UI update events if your
application has a lot of windows. If you set the value to -1 or
greater than 0, you may also need to call wxWindow:updateWin-
dowUI/2 at appropriate points in your application, such as when
a dialog is about to be shown.
wxWidgets team. wx 2.1.1 wxUpdateUIEvent(3)