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Write "The Dialog manager and the Widgets"

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Pavel Roskin 2003-10-25 00:36:46 +00:00
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@ -34,12 +34,12 @@ o This code is distributed under the GNU General Public License and
* Code structure. * Code structure.
The program uses extensively the dialog manager written by Radek The program uses extensively the dialog manager written by Radek
Doulik. To understand how the dialog manager works, please read Doulik. To understand how the dialog manager works, please read the
the dlg.c and dlg.h. You will find the basic widgets in the file dialog.c and dialog.h. You will find the basic widgets in the files
widget.c and the widget.h file. If you understand this two files, widget.c and widget.h. If you understand these files, you are done.
you are done. The files option.c and boxes.c contain some examples The files option.c and boxes.c contain some examples of how the
of how the dialog manager functions are used. For a more complete dialog manager functions are used. For a more complete example, take
example, take a look at the main.c file. a look at the main.c file.
The file util.c has a lot of utility functions. Get familiar with The file util.c has a lot of utility functions. Get familiar with
them, they are very simple. them, they are very simple.
@ -107,6 +107,54 @@ compatible with Slang.
* The Dialog manager and the Widgets * The Dialog manager and the Widgets
The Dialog manager and the Widget structure are implemented in
src/dialog.c. Everything shown on screen is a dialog. Dialogs contain
widgets, but not everything on screen is a widget. Dialogs can draw
themselves.
Dialogs are connected into a singly linked list using "parent" field.
Currently active dialog is saved in current_dlg variable. The toplevel
dialog has parent NULL. Usually it's midnight_dlg.
parent parent
current_dlg ------->another dialog-- ... -->midnight_dlg
When the screen needs to be refreshed, every dialog asks its parent to
refresh first, and then refreshes itself.
A dialog is created by create_dlg(). Then it's populated by widgets
using add_widget(). Then the dialog is run by calling run_dlg(), which
returns the id of the button selected by the user. Finally, the dialog
is destroyed by calling destroy_dlg().
Widgets are placed to a doubly linked circular list. Each widget has
previous and next widget.
prev next prev next
widget1 <---------> widget2 <---------> widget3
^ ^
-----------------------------------------
next prev
Pressing Tab moves focus to the "next" widget, pressing Shift-Tab moves
focus to "prev". The tab order is equal to the add order except some
old code that use the reverse order by setting DLG_REVERSE flag in
create_dlg() call. Please don't use reverse order in the new code.
The initial widget to get focus can be selected by calling
dlg_select_widget().
When creating a dialog, you may want to use a callback that would
intercept some dialog events. However, many widgets will do the right
thing by default, so some dialogs can work just fine without callbacks.
There are also widget events, which are sent by the dialog to individual
widgets. Some widgets also have user callbacks.
To create your own widget, use init_widget(). In this case, you must
provide a callback function. Please note that it's not the same as the
user callback in some widgets.
** Button widget ** Button widget
** Check box widget ** Check box widget