9.2 The class hierarchy for DUIM-Frames
9.2.3 Subclasses of <frame-event>
The <frame-event> class provides a number of subclasses that describe various events that can occur in frames. These subclasses are shown in Table 9.3.
<frame-event> |
| |
| <frame-created-event> | |
<frame-destroyed-event> | ||
<frame-mapped-event> | ||
<frame-unmapped-event> | ||
<frame-exit-event> | ||
<frame-exited-event> | ||
<application-exited-event> |
The name of each of these subclasses accurately reflects the type of event that they are used to represent. The classes <frame-created-event> and <frame-destroyed-event> represent a frame being created or destroyed. The classes <frame-mapped-event> and <frame-unmapped-event> represent the events that occur when a frame is displayed on the computer screen or removed from it. The class <frame-exit-event> represents the act of exiting a frame, and the class <frame-exited-event> represents the event where a frame has been successfully exited.
In addition, the class <frame-exited-event> has a subclass <application-exited-event>. This is reserved for the special case where the frame that has been exited is actually the parent frame for the whole application, in which case the whole application is exited, together with any other frames that may have been spawned as a result of using the application.
Note: The classes <frame-mapped-event> and <frame-unmapped-event> are distinct from the classes <frame-created-event> and <frame-destroyed-event>. A frame is not necessarily mapped as soon as it is created, and any frame can be unmapped from the screen without actually destroying it (for example, a frame may be iconized).