Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) - Manual (Page 113)

C H A P T E R 3
Views
About Views 3-29
5. The viewChildren and stepChildren slots are read and the child views
are instantiated using this same process. As part of the process, the following
messages are sent to each child view, in this order:
ViewSetupFormScript ,
ViewSetupChildrenScript , and ViewSetupDoneScript .
6. The ViewSetupDoneScript message is sent to the view.
7. The view is displayed if its vVisible viewFlags bit is set.
8. The ViewShowScript message is sent to the view and then the
ViewDrawScript message is sent to the view. (Note that the
ViewShowScript message is not sent to any child views, however.)
9. Each of the child views is drawn, in hierarchical order, and the
ViewDrawScript message is sent to each of these views, immediately
after it is drawn.
As you can see from step 5, when a view is opened, all child views in the hierarchy
under it are also shown (as long as they are flagged as visible). A nonvisible child
view can be subsequently shown by sending it the
Open message—as long as it
has been declared.
Closing a View 3
When you send a view the Close message, the graphic representation of the view
(and of all of its child views) is destroyed, but the view memory object is not
necessarily destroyed. There are two possibilities:
■ If the view was declared, and the view in which it was declared is still open, the
frame is preserved. You can send the view another
Open or Toggle message to
reopen it at a later time.
A view memory object is finally destroyed when the view in which it was
declared is closed. That is, when a view is closed, all views declared in it are
made available for garbage collection.
■ If the view being closed was not declared, both its graphic representation and its
view memory object are made available for garbage collection when it is closed.
When a view is closed, the following steps occur:
1. If the view is closing because it was directly sent the Close or Toggle
message, the system sends it the ViewHideScript message. (If the view
is closing because it is a child of a view being closed directly, the
ViewHideScript message is not sent to it.)
2. The graphic representation of the view is removed from the screen.
3. The view is sent the ViewQuitScript message.
The view itself may or may not be marked for garbage collection, depending on
whether or not it was declared.