Developer

API Reference

Widget Events

Brew Release
Brew MP 1.0.2
See Also
Description
The widget framework defines a small set of BREW events used to notify objects of various state or property changes involving a widget object. These events are sent to objects in addition to the normal set of BREW interface events such as key press events and other UI related events. A widget's event handler should be prepared to handle these events in whatever manner is appropriate for the behavior of that object. For example, the EVT_WDG_GETPROPERTY event will be sent to an widget to retrieve attributes or characteristics that apply to that particular object. To illustrate, a widget that contains a display banner of some sort would likely respond to an EVT_WDG_GETPROPERTY event specifying WID_TITLE as the requested property type, by returning the text of the widget's display banner.
The table below lists the AEE event codes supported by the widget framework, identifying the data structure that will be sent with the notification.
Definition
AEE Event Code                Description
--------------                ------------------------------------------------------
EVT_WDG_SETFOCUS:             The focus for this widget has changed or has been cleared.
                              The 'wParam' parameter of the event contains a boolean value
                              indicating whether or not the new focus item should become
                              active.  The widget receiving this event should return TRUE
                              if it accepts the focus, FALSE if it does not, and may choose
                              to invalidate itself or respond to the focus change in some
                              other meaningful way. The helper function, IWidget_SetFocus(),
                              is also available.  

EVT_WDG_CANTAKEFOCUS:         The widget is being asked if it can take focus. The 'dwParam'
                              should be a pointer to a boolean in memory, which will be
                              set to either TRUE (if the widget can take focus) or FALSE
                              (if the widget is unable to take focus).  The helper function,
                              IWidget_CanTakeFocus(), is also available.
                              
EVT_WDG_HASFOCUS:             The widget is being asked if it currently has focus.  The
                              'dwParam' should be a pointer to a boolean in memory, which will
                              be set to either TRUE (if the widget currently has focus) or
                              FALSE (if the widget does not currently has focus).  The
                              helper function, IWidget_HasFocus(), is also available.

EVT_WDG_GETPROPERTY:          The widget is being asked to return a particular property, as
                              specified in the 'wParam' parameter, returning the value of the
                              property in the buffer pointed to by the 'dwParam' parameter.
                              Widget properties are defined in AEEWidgetProperties.h and include
                              attributes such as color, border width, shadowing, etc.  The
                              widget receiving this event should return TRUE if it is able to
                              retrieve the requested property, FALSE if no such property exists
                              for the widget.
                              
EVT_WDG_SETPROPERTY:          The widget is being asked to set the value for a particular
                              property, as specified in the 'wParam' parameter.  The 'dwParam'
                              parameter of the event will contain the property's new value.
                              Widget properties are defined in AEEWidgetProperties.h and include
                              attributes such as color, border width, shadowing, etc.  The
                              widget receiving this event should return TRUE if it is able to
                              successfully set the specified property, FALSE if no such property
                              exists for the widget.


EVT_WDG_WINDOWSTATUS:         This event is used by WindowManager to provide window status
                              to the widget that was used to create the window. Widgets, by 
                              themselves, do not handle this event and widget based applications
                              can ignore this event. Window-based applications should set a handler
                              on the widget, which is used to create the window and look for this
                              property for various window status events like creation, removal of 
                              the window. 
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