Besides GnomeApp, the libgnomeui library contains a whole number of other
objects and widgets, including standard dialogs, session managment, MDI, and
other utility widgets.
A D V E R T I S E M E N T
It also contains the GnomeCanvas widget, which deserves
separate treatment. This is the library that makes the programmers life easy. It
is important that you use these widgets rather then plain GTK+ ones as these
widgets give you consistency and features that a user of a GNOME application
expects.
Stock Icons
Since most of the time you will want to use standard buttons and menu
items (such as Open or Save
as...), and you want to provide icons with the menu items or tool-bar
buttons or just dialog buttons, to make it easier to navigate, you can use
some of the predefined icons from gnome-libs. These
are called Stock Icons. You have already seen an
example of how to use stock menu icons and regular stock icons in menus and
tool-bars (you just use the proper define from
libgnomeui/gnome-stock.h). There are also stock buttons, where you can
get back a button widget based on a stock description.
Here is a list of the normal gnome stock icons,
these are regular sized for use in tool-bars and other places where you need
a normal sized icon. They are given as defines of string constants and their
meaning should be obvious.
If you need to use these outside of GnomeUIInfo, you
need to get the widget with the pixmap. What you do is you call the
gnome_stock_pixmap_widget function with your main
window as the first argument (so that it can copy it's style) and the icon
name (one of the above defines) as the second argument. It returns a new
widget which you can just use as a pixmap.
For menus you want to use the _MENU_ variety of
the stock pixmaps. These are smaller and these should be the ones you use
for the stock menu items in your GnomeUIInfo
definitions.
If you are building the menu yourself and just want to get a menu-item
that's built with the stock icon and a label, you can use the
gnome_stock_menu_item convenience routine. It takes
the stock icon type (one of the defines above) as the first argument, and
the menu text as the second argument, and it returns a newly created
menu-item widget.
Then there are stock buttons. These are for use in your dialogs (see the
next section).
To get a button widget with the stock icon and text, you can just use the
function gnome_stock_button with the button type
(one of the above defines) as the argument. Now sometimes you want to create
a mixture of stock or ordinary buttons, what you can do is call the
gnome_stock_or_ordinary_button function with either
the type of a stock button or just a text for the button label. The function
checks if it is one of the above strings, and if it's not it creates an
ordinary button widget with the text as the label. Here is an example, it
creates three buttons packing them into a box 'box' (I don't include code to
make the box), two of the buttons are stock and one is normal:
GtkWidget *w;
GtkWidget *box;
int i;
char *buttons[]={
GNOME_STOCK_BUTTON_OK,
GNOME_STOCK_BUTTON_CANCEL,
"Foo",
NULL
};
...
/* loop through all strings in buttons array */
for(i = 0; buttons[i] != NULL; i++) {
/* create the button, stock or ordinary */
w = gnome_stock_or_ordinary_button(buttons[i]);
/* show and pack it */
gtk_widget_show(w);
gtk_box_pack_start(GTK_BOX(box),w,FALSE,FALSE,0);
/* we should bind signals and other stuff here */
...
}
Dialogs
Generic Dialogs
If you need to create you own custom dialog,
gnome-dialog is the way to do it. It can handle both modal and
non-modal dialogs, although, it's definitely much more friendly to the
users of your program if you use a non-modal dialog box, if at all
possible, although non-modal dialog boxes tend to have problems
associated with them, and sometimes can cause strange bugs, for example
if a non-modal dialog box is associated with a window, you'd better bind
the destroy signal of the window and set it to
destroy the dialog box as well, since otherwise it could hang around
even though the window or document it was supposed to act on is already
dead. However modal dialogs (while definitely easier to program) are
usually pretty annoying to use, so avoid them if you at all can.
To make a new GnomeDialog widget, just use
the gnome_dialog_new function. You pass the
title of the dialog as the first argument, and then multiple arguments
as the button titles terminated by a NULL. The button titles can also be
the GNOME_STOCK_BUTTON_* definitions if you want
stock buttons on your dialog. Then you need to add content to the
dialog, the dialog is created with a vertical box (GtkVBox)
for you to use, just by using
GNOME_DIALOG(dialog)->vbox. Into that you add your content.
You should also set the parent of the dialog to be your main
application window (your GnomeApp). This allows the windowmanager to
handle the window more appropriately rather then just like a generic
window. You accomplish it with the following call:
At this point you have to decide if you want to do a modal dialog or
a non-modal dialog. In case you want to do a modal dialog, all you need
to do is to call gnome_dialog_run_and_close
function and it will run the dialog, wait for a user to press a button
or close the dialog, and then close the dialog. This function will
return the number of the button that was pressed or -1 if the dialog was
just closed. In case you don't want to close the dialog when just any
button is pressed, you use the gnome_dialog_run
function, and after you get a result, do what you need to do for that
particular button press. Then if you want to run the dialog more, you
just loop back to gnome_dialog_run, and if you
want to close, you run gnome_dialog_close.
Here's an example of the second scheme.
GtkWidget *dlg;
GtkWidget *label;
int i;
...
/*create a new dialog, DON'T forget the NULL on the end,
it is very important!*/
dlg = gnome_dialog_new("A Dialog",
GNOME_STOCK_BUTTON_OK,
GNOME_STOCK_BUTTON_APPLY,
GNOME_STOCK_BUTTON_CLOSE,
NULL);
/* here we assume that app is a pointer to our GnomeApp window */
gnome_dialog_set_parent(GNOME_DIALOG(dlg), GTK_WINDOW(app));
...
/*add some content to the dialog here*/
label = gtk_label_new("Some random content");
gtk_box_pack_start(GTK_BOX(GNOME_DIALOG(dlg)->vbox),label,
FALSE,FALSE,0);
...
/*set up an infinite loop*/
for(;;) {
i = gnome_dialog_run(GNOME_DIALOG(dlg));
if(i == 0 || i == 2) {
/*the user pressed OK or close, so we will get
out of the loop and close the dialog, or the
user pressed */
gnome_dialog_close(GNOME_DIALOG(dlg));
break;
} else if(i < 0) {
/*the user closed the dialog from the window
manager*/
break;
} else if(i == 1) {
/*user pressed apply we don't want to close*/
...
}
}
By default the dialog is destroyed when closed, so you don't have to
worry about it's destruction. You can change this behavior if you wish
though.
If you are doing a non-modal dialog box, things get a little more
complicated. You create the dialog as above, but then you bind the
clicked signal of the
GnomeDialog widget. That signal has as it's second argument the
button number that was pressed. After that you should use the
gnome_dialog_set_close function to tell
GnomeDialog that we want to close the dialog
when the user first presses any button, if you want that behavior,
otherwise you'll have to do gnome_dialog_close
in the clicked signal handler for the buttons
you want to close on. After that is set up you just
gtk_widget_show the dialog. An example follows:
/*the clicked signal handler*/
static void
dialog_clicked(GnomeDialog *dlg, int button, gpointer data)
{
switch(button) {
case 1:
/*user pressed apply*/
...
return;
case 0:
/*user pressed OK*/
...
/*fall though to close*/
case 2:
/*user pressed close*/
gnome_dialog_close(dlg);
break;
}
}
/*somewhere else in the source file*/
...
GtkWidget *dlg;
...
/*create a new dialog, DON'T forget the NULL on the end, it
is very important!*/
dlg = gnome_dialog_new("A Dialog",
GNOME_STOCK_BUTTON_OK,
GNOME_STOCK_BUTTON_APPLY,
GNOME_STOCK_BUTTON_CLOSE,
NULL);
/* here we assume that app is a pointer to our GnomeApp window */
gnome_dialog_set_parent(GNOME_DIALOG(dlg), GTK_WINDOW(app));
...
/*add some content to the dialog here*/
...
/*bind the clicked handler*/
gtk_signal_connect(GTK_OBJECT(dlg),"clicked",
GTK_SIGNAL_FUNC(dialog_clicked),
NULL);
/*show the dialog, note that this is not a modal dialog,
so the program doesn't block here, but continues*/
gtk_widget_show(dlg);
This implements the same dialog as the modal example above, only non
modal. Make sure that you have some way of destruction of the dialog in
case it's no longer relevant, for example if a dialog is to modify some
object, it should be destroyed when that object is destroyed.
Message Box
GnomeMessageBox is an object derived from
GnomeDialog. As such you use it in the exact
same manner, the only difference here is that it automatically sets up
the insides of the dialog to be a single label and an icon of the
selected message box type. The message box types are as follows:
To create a message box, you use the function
gnome_message_box_new with the first argument being the message
text, the second argument being the type of the message box (one of the
defines above), and then any number of buttons terminated by a NULL
exactly as in the GnomeDialog's case. After
created it is again used exactly the same as
GnomeDialog.
Property Dialogs
If you have some properties to set in your application, you should
use a GnomePropertyBox dialog for the
preferences to make the applications more consistent. Again this object
is derived from GnomeDialog so it's use is
similar. But GnomePropertyBox defines some new
signals, namely apply and
help. They both get passed the page number as the second argument.
For help you should use this to display the proper help page, however
for apply, this was created for adding a per-page apply button, which
was not realized yet, so you should ignore any apply
signal with the page number other then -1, which is the
global apply. This can be done with a simple if
statement at the top of your apply routine. You can choose to be
per-page apply ready, by doing a per-page apply
in your code, but it is not sure if this code will ever get completed.
It should be safe to do just the global apply as that is the only thing
implemented in gnome-libs 1.0.
To use property dialogs, you call
gnome_property_box_new, which will create a completely new dialog
for you with a notebook and the four buttons. OK,
which will call your apply handler for all pages and then for the -1
page, and then it will close the dialog, Apply,
which will call the apply handler for all pages and then for the -1
page, Close, which will just close the dialog,
and Help which will call your help handler if
you bound it. You then connect the apply signal
to your apply handler, and most likely the destroy
signal on the property box to destroy the data associated with the
property box when it closes. You then create the different pages for
your property box and add them with,
gnome_property_box_append_page, which takes your page as the second
argument and a label as the third (usually this will be just a
GtkLabel). You also want to connect the
different signals for the widgets on your pages, to mark the property
box as changed (otherwise the Apply and OK buttons will not be
sensitive). You do this by calling
gnome_property_box_changed every time the user changed something
with the widgets. For example on entry (and derived) widgets you connect
to the changed signal. Example follows:
/*apply handler*/
static void
property_apply(GnomePropertyBox *box, int page_num, gpointer data)
{
/*ignore page numbers other then -1*/
if(page_num!=-1)
return;
/*do your apply routine here*/
...
}
...
/*somewhere else in the source file*/
GtkWidget *pbox;
GtkWidget *widget;
...
pbox = gnome_property_box_new();
gtk_signal_connect(GTK_OBJECT(pbox),"apply",
GTK_SIGNAL_FUNC(property_apply),NULL);
...
/*you create a page for the property box and added it to the
container called widget*/
gnome_property_box_append_page(GNOME_PROPERTY_BOX(pbox),
widget,
gtk_label_new("SomePage"));
/*then add other pages in similar manner*/
...
/*we show the dialog box*/
gtk_widget_show_all(pbox);
File Picking Dialog
Gnome doesn't have it's own file picking dialog, although this is
planned for the future, for now you need to use the regular
GTK+ file dialog.
Use of the file dialog is very simple. You create the dialog with
gtk_file_selection_new, passing it the title of
the dialog box as the argument. After this you bind the clicked signal
on the OK and Cancel
buttons. For example for a loading dialog box, you could check that the
file is of the correct type when the user presses OK and if so then
close the dialog (usually with gtk_widget_destroy).
Or for saving dialog, you could ask if the file exists. File selection
dialog boxes are usually safe and simple to do non-modal. Just make sure
you'd destroy the file dialog box when the object or window it's
supposed to work with. Here's the routine that invokes the save as
dialog for Achtung, which is a presentation
program we're working on.
void
presentation_save_as (AchtungPresentation *p)
{
GtkFileSelection *fsel;
g_return_if_fail (p != NULL);
g_return_if_fail (p->doc != NULL);
/* create a new file selection widget */
fsel = GTK_FILE_SELECTION
(gtk_file_selection_new (_("Save presentation as")));
if (p->real_file && p->filename)
gtk_file_selection_set_filename (fsel, p->filename);
gtk_object_set_data(GTK_OBJECT(fsel),"p",p);
/* Connect the signals for Ok and Cancel */
gtk_signal_connect (GTK_OBJECT (fsel->ok_button), "clicked",
GTK_SIGNAL_FUNC (save_ok), fsel);
gtk_signal_connect_object
(GTK_OBJECT (fsel->cancel_button), "clicked",
GTK_SIGNAL_FUNC (gtk_widget_destroy),
GTK_OBJECT(fsel));
/* set the position at the mouse cursor, we do this because this
is not a gnome dialog and thus it isn't set for us. You
shouldn't do this for normal gnome dialogs though */
gtk_window_position (GTK_WINDOW (fsel), GTK_WIN_POS_MOUSE);
/*if the presentation dies so do it's dialogs*/
gtk_signal_connect_object_while_alive
(GTK_OBJECT (p), "destroy",
GTK_SIGNAL_FUNC (gtk_widget_destroy),
GTK_OBJECT(fsel));
gtk_widget_show (GTK_WIDGET (fsel));
}
This is actually a save_as method for
AchtungPresentation object in object oriented speak.
AchtungPresentation is a GtkObject we use for
storing all the presentation data (This is a nice example of how to use
GtkObject for things not directly related to widgets or GUI
programming). First we check the arguments to the function with
g_return_if_fail which is for debugging
purposes. Then we create a new GtkFileSelection
with a title of "Save presentation as". Ignore the
_() macro around the string for now, it's used for
internationalization. Afterwards we check if the presentation already
has a filename associated with it, and if so we set the filename on the
file selection dialog to that. After that we connect the the
OK button to a routine called
save_ok defined elsewhere in the file and pass
the file selection dialog as a data argument. Then we use
connect_object to bind the
Cancel button to destroying the file selection dialog. The
connect_object method is similar to regular
connect but when it calls the function itself it
will pass the object from the data field as the first argument of the
function. So connecting to gtk_widget_destroy
will destroy the object passed in the data field, which is the file
selection dialog. Then we position the dialog near the mouse button. In
the future when this dialog is derived from
GnomeDialog, you will not need to and actually should not do that,
as that will be done according to use preferences as for all the other
gnome dialogs. After this we use yet another signal connection method
... this time gtk_signal_connect_object_while_alive,
which is similar to connect_object, but has a
nice twist to it. The signal will be disconnected when the object passed
in the data field dies. This needs to happen as the file dialog will
most likely be destroyed before the the presentation itself is, then
when the presentation is destroyed itself, it would try to destroy an
already non-existent file selection dialog and most likely cause a
segmentation fault and crash. This way it is safe and if the file
selection dialog is still around when the presentation is destroyed, it
is destroyed with it.
About Box
You will probably want to have an "About" entry in the "Help" menu of
your application, and it should display the standard about box. There is
a dialog in gnome for just this sort of puprose, the GnomeAbout object.
It is created with the gnome_about_new which has the following prototype
GtkWidget* gnome_about_new(const gchar *title, /* Name of the application. */
const gchar *version, /* Version. */
const gchar *copyright, /* Copyright notice
(one line.) */
const gchar **authors, /* NULL terminated list of
authors. */
const gchar *comments, /* Other comments. */
const gchar *logo /* A logo pixmap file. */
);
After you create the dialog box, you should set it's parent to be
your application window with gnome_dialog_set_parent.
And then you can just show the dialog. The following implements an about
box dialog, we assume that VERSION has been #define'd to be the string
with the version number. We also pass NULL as the logo, meaning we have
no logo picture to display.
GtkWidget* dlg;
char *authors[] = {
"George Lebl",
NULL;
};
dlg = gnome_about_new("Some application", /* Name of the application. */
VERSION, /* Version. */
"(c) 1999 George Lebl, /* Copyright notice
(one line.) */
authors, /* NULL terminated list of
authors. */
"Just some application, "
"blah blah blah", /* Other comments. */
NULL /* A logo pixmap file. */
);
gnome_dialog_set_parent(GNOME_DIALOG(dlg), GTK_WINDOW(app));
gtk_widget_show(dlg);
Entries
Sometimes, especially in properties dialogs, you want fields for entering
text, files, pixmaps, icons or double precision numbers. This is what the
gnome-*entry widgets do.
GnomeEntry
This is an entry for regular text, but it includes history of
previously entered values. Note that this widget is not derived from
GtkEntry, but owns such a widget. This means
that you can't use GtkEntry methods on this
object directly, but you need to get a pointer to the
GtkEntry object inside
GnomeEntry. When you call gnome_entry_new,
you pass a history_id string to it. This is a
unique identifier to identify this entry, or this type of entries in
your application. All the entries that share this
history_id will have common history of values. After you create a
GnomeEntry you use the
gnome_entry_gtk_entry function to get a pointer to the
GtkEntry object inside and bind any signals or
manipulate text with that instead. Here is an example:
GtkWidget *gnomeentry;
GtkWidget *gtkentry;
...
gnomeentry = gnome_entry_new("text1");
/* get the GtkEntry to bind a "changed" signal to figure out when the
user changed the entry */
gtkentry = gnome_entry_gtk_entry(GNOME_ENTRY(gnomeentry));
gtk_signal_connect(GTK_OBJECT(gtkentry),"changed",
GTK_SIGNAL_FUNC(entry_changed), NULL);
GnomeFileEntry
GnomeEntry is a basis for
GnomeFileEntry. Again it is not derived, but
GnomeEntry is owned by GnomeFileEntry. This
type of hierarchy is throughout all the gnome entry widgets.
GnomeFileEntry adds a browse button on the right
side of the entry, and also accepts file drops from the file manager for
example. It's use is extremely similar to GnomeEntry.
You create the entry with gnome_file_entry_new.
The first argument is the history_id of the
GnomeEntry, and the second argument is the title
of the browse dialog box. To get the GtkEntry,
you again use the gtk_entry method, named
gnome_file_entry_gtk_entry. To finally get the filename, you can get
the exact text from the GtkEntry, or you might
use a convenience method,
gnome_file_entry_get_full_path, which takes a flag
file_must_exist as it's second argument. If this
flag is set, the function returns NULL if the file doesn't exists. If
the flag is not set or the file does exist, the function returns the
full path to the file.
GnomePixmapEntry
This is an entry for entering pixmaps (Images) of any size. It again
includes (not derives from) GnomeFileEntry, so
it can do everything the file entry can (including accepting drops).
However this entry adds a preview box for the pixmap above the entry.
Also it's file selection dialog includes a preview box to the right side
of the file list. It's use is again very similar to the entries above.
You call gnome_pixmap_entry_new with the same
arguments as GnomeFileEntry, with an added flag,
do_preview. This flag specifies if the preview
box is visible or not. But be careful, it doesn't save memory not to
show the preview, it just saves space. Again you use a
gnome_pixmap_entry_gtk_entry to get the
GtkEntry widget. To get a filename of the the
pixmap, if it could be loaded as an image for the preview, you can use
gnome_pixmap_entry_get_filename, which returns
NULL if the pixmap files doesn't exist or could not be loaded, and the
full filename otherwise.
GnomeIconEntry
The icon entry is very similar to the
GnomePixmapEntry, but it is meant for images in the standard 48x48
icon size. Also instead of the preview box, there is a button with the
image scaled to 48x48. If you press the button you get a listing of
images from the same directory as the current icon. To create an icon
entry use gnome_icon_entry_new with
history_id and
browse_dialog_title string arguments. Once you need an existing icon
that is a real image, you use
gnome_icon_entry_get_filename which works just like
gnome_pixmap_entry_get_filename. You can also
get the GtkEntry by using
gnome_icon_entry_gtk_entry. Example:
GtkWidget *iconentry;
GtkWidget *gtkentry;
char *somefilename;
...
iconentry = gnome_icon_entry_new("icon","Browse...");
/* we want to set 'somefilename' as default icon */
gnome_icon_entry_set_icon(GNOME_ICON_ENTRY(iconentry), somefilename);
/* we get the GtkEntry to figure out when we changed */
gtkentry = gnome_icon_entry_gtk_entry(GNOME_ICON_ENTRY(iconentry));
gtk_signal_connect(GTK_OBJECT(gtkentry),"changed",
GTK_SIGNAL_FUNC(entry_changed), NULL);
...
/* here we want to get the selected icon */
char *icon;
icon = gnome_icon_entry_get_filename(GNOME_ICON_ENTRY(iconentry);
...
/* make sure to free icon after use */
g_free(icon);
GnomeNumberEntry
GnomeNumberEntry is an entry widget for
entering double precision numbers with a calculator. Most of the time
for number entries you want to use the GtkSpinButton
widget, however for applications such as mortgage calculators, or
finance programs, where calculations are necessary, you will want to use
this entry type. Basically it's a GnomeEntry
widget with a button on the right side of it which calls up a dialog
with a calculator. The user can use the calculator and press OK and the
number entry is updated to what it was on the calculator. To create a
number entry widget, just use gnome_number_entry_new,
passing it the history_id as the first argument
and the title of the calculator dialog as the second argument. To get
the GtkEntry widget just use
gnome_number_entry_gtk_entry. To get the number as a
double value, use
gnome_number_entry_get_number method.
Using Images
When you need to use images in your apps, most likely you'll want the
GnomePixmap widget. It's advantage is that it makes
using images much easier without having to learn imlib, which is the image
library used by this widget.
There are numerous new functions for
GnomePixmap, depending on the source of the pixmap.
The most used will probably be
gnome_pixmap_new_from_file which takes a filename which is an image
loadable by imlib and creates a pixmap widget for you. There is also
gnome_pixmap_new_from_file_at_size to which you pass
also the size to which the image should be scaled. If you have already
loaded the image with imlib (in case you wanted to do other things to the
pixmap first), you can use gnome_pixmap_new_from_imlib
and gnome_pixmap_new_from_imlib_at_size. Which take
a GdkImlibImage as the first argument. If you
already have a pixmap widget and want to change the image inside it, you can
use the gnome_pixmap_load_* which have almost the
same syntax as the new functions, except that you pass the
GnomePixmap as the first argument, and then the rest
of the arguments as above, and of course replace the _new_from_ for _load_.
Here's an example of it's use:
GtkWidget *pix;
...
/*load somefile.png and scale it to 48x48*/
pix = gnome_pixmap_new_from_file_at_size("somefile.png",48,48);
/*now you can pack pix somewhere just like any other widget*/
...
/*now we want to change the files to otherfile.png and do no
scaling*/
gnome_pixmap_load_file(GNOME_PIXMAP(pix),"otherfile.png");
Session Management
Your app should be able to save it's settings and restore them when the
user restarts your application, it should also be able to do this for
several different sessions. For instance the user might have a normal
session, but sometimes log into a special session where he has different
settings in applications. gnome-libs actually hides
the ugly details of this. For the most part you do not need to worry about
the real details of session management, unless you wish to do something very
clever or if your app does some complicated state saving. To do simple
session saving all you need is the following code (mostly taken from
gnome-hello-4-SM example program):
/*the save_yourself handler, you can safely ignore most of the
parameters, and just save your session and return TRUE*/
static int
save_yourself(GnomeClient *client, int phase,
GnomeSaveStyle save_style, int shutdown,
GnomeInteractStyle interact_style, int fast,
gpointer client_data)
{
/*get the prefix for our config*/
char *prefix= gnome_client_get_config_prefix (client);
/*this is a "discard" command for discarding data from
a saved session, usually this will work*/
char *argv[]= { "rm", "-r", NULL };
/* Save the state using gnome-config stuff. */
gnome_config_push_prefix (prefix);
gnome_config_set_int("Section/Key",some_value);
...
gnome_config_pop_prefix ();
gnome_config_sync();
/* Here is the real SM code. We set the argv to the
parameters needed to restart/discard the session that
we've just saved and call the
gnome_session_set_*_command to tell the session
manager it. */
argv[2]= gnome_config_get_real_path (prefix);
gnome_client_set_discard_command (client, 3, argv);
/* Set commands to clone and restart this application.
Note that we use the same values for both -- the
session management code will automatically add
whatever magic option is required to set the session
id on startup. The client_data was set to the
command used to start this application when
save_yourself handler was connected. */
argv[0]= (gchar*) client_data;
gnome_client_set_clone_command (client, 1, argv);
gnome_client_set_restart_command (client, 1, argv);
return TRUE;
}
static void
die (GnomeClient *client, gpointer client_data)
{
/* Just exit in a friendly way. We don't need to
save any state here, because the session manager
should have sent us a save_yourself-message
before. */
gtk_exit (0);
}
...
GnomeClient *client;
...
/*this is somewhere in your main function presumably.
make sure this is done AFTER the gnome_init call!*/
/* Get the master client, that was hopefully connected to the
session manager int the 'gnome_init' call. All communication
to the session manager will be done with this master client. */
client = gnome_master_client ();
/* Arrange to be told when something interesting happens. */
gtk_signal_connect (GTK_OBJECT (client), "save_yourself",
GTK_SIGNAL_FUNC (save_yourself),
(gpointer) argv[0]);
gtk_signal_connect (GTK_OBJECT (client), "die",
GTK_SIGNAL_FUNC (die), NULL);
/*check if we are connected to a session manager*/
if (GNOME_CLIENT_CONNECTED (client)) {
/*we are connected, we will get the prefix under which
we saved our session last time and load up our data*/
gnome_config_push_prefix
(gnome_client_get_config_prefix (client));
some_value = gnome_config_get_int("Section/Key=0");
gnome_config_pop_prefix ();
} else {
/*we are not connected to any session manager, here you
will just initialize your session like you normally
do without a session manager*/
...
}
This is a very simple session management which will be enough for most
programs, for more information on session management, you should consult the
gnome developer documentation which should be available by now.
Multiple Document Interface
The Main MDI Window
If your app handles documents, most likely you will want it to handle
multiple documents at one time. Gnome provides an MDI model that is
customizable by the user and simple to use. They can use three models of
the document display. Either a notebook style which is the most useful
one, where documents can be docked in notebooks, and can be dragged out
into separate windows if desired. Or a toplevel style where each
document is a separate toplevel window. Or finally a modal style where
there is only one window and the documents must be switched though a
menu. (Note that the examples here are taken from the
gnome-hello-7-mdi example app in
gnome-libs, slightly modified. Also note that
this example is no longer in gnome-libs, but I reproduce here the really
important parts of that example)
To use the MDI features. You basically replace the the
gnome_app_new call with
gnome_mdi_new with the same arguments as
gnome_app_new. To add menus and tool-bar, you use
gnome_mdi_set_menubar_template and
gnome_mdi_set_toolbar_template with the
GnomeUIInfo as the argument. For MDI, these aren't the actual menus, as
it will add it's own items to the menus of each child. After this you
set where the menu additions take place. You call
gnome_mdi_set_child_menu_path to the toplevel menu name after which
the child's own menus are inserted. This is the "File" menu in most
cases. Then you want to specify the path (menu name) to the menu into
which you want to insert a list of the children, you do this by calling
gnome_mdi_set_child_list_path with the name of
the menu and add a '/' on the end of it to specify that you want to
insert those items into the menu, not after the menu. Example:
GtkWidget *mdi;
...
mdi = gnome_mdi_new("gnome-hello-7-mdi", "GNOME MDI Hello");
...
/*main_menu and toolbar_info are the menu and tool-bar
descriptions*/
gnome_mdi_set_menubar_template(mdi, main_menu);
gnome_mdi_set_toolbar_template(mdi, toolbar_info);
/* and document menu and document list paths (see
gnome-app-helper menu insertion routines for details) */
gnome_mdi_set_child_menu_path(GNOME_MDI(mdi), "File");
gnome_mdi_set_child_list_path(GNOME_MDI(mdi), "Children/");
In our GnomeUIInfo structures we have defined a menu named "File" and a
menu named "Children". The children menu was not given any items, it's
just an empty menu.
Then you should open the main toplevel window with
gnome_mdi_open_toplevel. This will open a
toplevel window without any children. If you wish to use MDI's session
management functionality, you can define a function that creates a child
given it's name. This is done with the
gnome_mdi_restore_state method, which takes the config path as the
second argument and a function pointer to a function which takes a
string and returns a new GnomeMDIChild widget (a
widget sub-classed from GnomeMDIChild actually).
Say for example you are using the session management shown above, so you
could use:
The restart_ok is a boolean value telling you if the loading actually
loaded all the data correctly.
You should also bind the destroy signal of
the mdi object to do gtk_main_quit when the mdi
is destroyed.
The MDI Children
For complicated apps, all children should be derived from the virtual
GnomeMDIChild object. For simple apps, you don't
need to derive a new object, you can just use the
GnomeMDIGenericChild, and use the fact that you can store arbitrary
data on arbitrary GtkObjects to store your own
data on the object.
To use the generic child object, you create it with
gnome_mdi_generic_child_new to which you pass
the name of the child. When you get the object, you will need to set it
up for your use. First you add a function for creating new views of the
same data. A view is just a different window displaying the same file or
data. This is done with a call to
gnome_mdi_generic_child_set_view_creator to which you pass a pointer
to a creator function which takes the child widget and a data pointer as
arguments and returns a data widget, which is not the actual child
widget, but actually the child of the
GnomeMDIGenericChild widget. After this you set the template for the
child's menus with gnome_mdi_child_set_menu_template,
to which you pass the GnomeUIInfo array pointer
of the child menu definitions. Then you should call
gnome_mdi_generic_child_set_config_func to set a function which
returns a newly allocated string to save in the config file. This string
will be used to load up the child next time you start and do the
gnome_mdi_restore_state call. It should probably
be a filename of the document, or some string from which you can
completely recreate that window/document. Then you need to call
gnome_mdi_generic_child_set_label_func with a
pointer to a function that takes the
GnomeMDIGenericChild as the first argument, the old label widget
pointer as the second argument, which would be null if no label widget
was yet set, and a data argument. This function can either create a new
label and destroy the old one, or just set the label if the label
exists. The label can be any widget, for example the
gnome-hello-7-mdi example code uses a horizontal box widget into
which it adds a pixmap and a gtk label. After this if you need to add
the child to the mdi yourself, if you are loading a new file for
example, you use gnome_mdi_add_child and
gnome_mdi_add_view, to add a new child and a new
view to the mdi. If you are creating a new child from the
gnome_mdi_restore_state function, you should
just return the child, the mdi will take care of adding it and adding
the appropriate views. You also probably want to set some data on the
child widget at this time to store your data with the object.
Here's a short example of creating a new child.
GnomeMDI *mdi;
...
GnomeMDIGenericChild *child;
...
/*create a new child named 'name'*/
if((child = gnome_mdi_generic_child_new(name)) != NULL) {
/*creator of a view*/
gnome_mdi_generic_child_set_view_creator
(child, my_child_create_view, NULL);
/*set a menu template for child menu*/
gnome_mdi_child_set_menu_template
(GNOME_MDI_CHILD(child), main_child_menu);
/*set function to get config string*/
gnome_mdi_generic_child_set_config_func
(child, my_child_get_config_string, NULL);
/*set function that sets or creates a label*/
gnome_mdi_generic_child_set_label_func
(child, my_child_set_label, NULL);
/* add the child to MDI */
gnome_mdi_add_child(mdi, GNOME_MDI_CHILD(child));
/* and add a new view of the child */
gnome_mdi_add_view(mdi, GNOME_MDI_CHILD(child));
}
Miscellaneous Widgets
Displaying text with GnomeLess
Sometimes you might want to display a file from disk, such as a
README, or perhaps display the results of running a certain command.
This is what the GnomeLess widget was written for. It provides simple
API to do these basic things, with minimum amount of work. First you
must create a new GnomeLess widget and put it somewhere into your
interface. You do this with the gnome_less_new
function. Then to show a file from disk, you call the
gnome_less_show_file method with the filename as
the second argument. Example:
GtkWidget *less;
...
less = gnome_less_new();
/* This will read the file "README" from disk and show it inside
the GnomeLess widget */
gnome_less_show_file(GNOME_LESS(less), "README");
If you want to show the result of a command, such as perhaps "ls",
you can call the gnome_less_show_command method
with the command as the second argument. Example:
GtkWidget *less;
...
less = gnome_less_new();
/* This will show the results of "ls" int he current directory inside
the GnomeLess widget */
gnome_less_show_command(GNOME_LESS(less), "ls");
Do note however that this will block the application. This call does not
return until the command ends execution. This means that you should not
use it for commands that take a long time to execute, because the user
interface would "freeze" until the command ended. For that you should
use use some alternate logic.
Web Links With GnomeHRef
Sometimes you might want to put a button in your app that starts a
browser for the user or points an already running browser to some
location. All you need to do is to call
gnome_href_new with an URL as the first argument and the label as
the second. This will create a button like widget, which you can place
anywhere in your application. It will then display the URL using the
gnome_url_show function. For example:
GtkWidget *widget;
...
widget = gnome_href_new("http://www.gnome.org", "The GNOME Website");
Selecting Icons With
GnomeIconSelection
Normally you will probably want to select icons using the
GnomeIconEntry widget, but sometimes you maybe want to put the icon
listing window directly into your application, without having to mess
with the icon listing yourself. This widget is only useful if you have
some directory from which to pick icons. You create the widget with the
gnome_icon_selection_new. Then when you want to
add a directory of icons, use
gnome_icon_selection_add_directory method with the argument being
the directory to add. You can add multiple directories. Then when you
have added all that you want, you have to call
gnome_icon_selection_show_icons and that will load and show the
icons. To select a specific icon, use the
gnome_icon_selection_select_icon with the filename of the icon to
select. The filename should be just the base name of the icon not the
entire path. Once you want to get the icon that was selected, you use
the gnome_icon_selection_get_icon method which
takes a boolean argument 'full_path' and returns a pointer to a string
with the file or NULL if nothing was selected. If that 'full_path'
argument is TRUE, the returned value will be the full path of the icon.
Note that the returned value points to internal memory so you should not
free it. Example:
GtkWidget *widget;
char *some_icon_directory;
char *some_other_icon_directory;
...
/* here we create the widget */
widget = gnome_icon_selection_new();
gnome_icon_selection_add_directory(GNOME_ICON_SELECTION(widget),
some_icon_directory);
gnome_icon_selection_add_directory(GNOME_ICON_SELECTION(widget),
some_other_icon_directory);
gnome_icon_selection_show_icons(GNOME_ICON_SELECTION(widget));
...
/* here we want to get the selection (as full path) */
char *filename;
...
filename = gnome_icon_selection_get_icon(GNOME_ICON_SELECTION(widget), TRUE);
