Re: [g-a-devel] Focus problems

[Bill Haneman <Bill Haneman Sun COM>]

Also Ashu:

If your object/container may sometimes contain a very large number of 
objects, you might consider using the MANAGES_DESCENDANTS state to 
inform the AT that the object potentially is too big to enumerate; some 
kinds of lists and tables use this state now, to help reduce performance 
issues.  Containers like this should emit 'active-descendant-changed' 
events when the local 'focus' changes - in such cases I don't believe 
that we emit 'focus:' as well. 

You will probably also need to implement AtkSelection, if your container 
allows the user to select items inside it.  There is also a distinction 
between 'selection' and 'focus', the active  descendant is normally 
"focussed" from the keyboard perspective, but not necessarily selected; 
this allows the user to keyboard navigate without changing the selection 
state of the container's children.  For instance gtktreeview allows 
'control arrow' navigation without moving the selection, and similar 
distinction is made in the nautilus icon view.

- Bill

padraig o'briain wrote:

> Ashu,
>
> You might also look at gtkhtml2/libgtkhtml/a11y/htmlviewaccessible.c.
> This code deals with a similar problem to yours.
>
> gtkhtml2 is used in GNOME's help browser, yelp. When a link is focused
> a "grab_focus" signal is emitted on the containing widget, a HtmlView.
> Its code is in gtkhtml2/libgtkhtml/view/htmlview.c.
>
> The function html_view_accessible_grab_focus_cb() ensure that the focus
> notification is received on the correct object.
>
> Padraig
>
> padraig o'briain wrote:
>  
>
> > Ashu,
> >
> > If you are creating your own AtkObjects you will also need to deal with
> > focus notification. If you want gnopernicus to become aware that an
> > object has received focus you need to call atk_focus_tracker_notify()
> > for the object which has focus.
> >
> > You could look at how we deal with this in gail.c.
> >
> > Padraig
> >
> > Ashu Sharma wrote:
> >
> >    
> >
> > > Hi again,
> > >
> > > I'm having some problems with the focus and how gnopernicus follows it.
> > >
> > > If we have a webpage which has a number of "widgets" on it (that are
> > > not actual GtkWidget's but are things directly drawn on the GdkWindow
> > > of the client area) and we manually draw focusrects around links etc,
> > > how do we notify atk so that gnopernicus queries us for that "widget"
> > > and reads it out.
> > >
> > > I have a GtkLayout on which the entire page is rendered and when the
> > > focus is on a link on the page, I create an AtkObject for it (with
> > > AtkAction, etc.) and issue the following notification:
> > >
> > > AtkStateSet *stateSet = my_link_ref_state_set (linkAtkObject);
> > > atk_state_set_add_state (stateSet, ATK_STATE_FOCUSED);
> > > atk_object_notify_state_change (linkAtkObject, ATK_STATE_FOCUSED, true);
> > >
> > > After this, gnopernicus does query the linkAtkObject for its details
> > > but never reads them out. Is this because there is no physical widget
> > > for the link? Or is it because the actual focus (gtk's focus) is on
> > > the GtkLayout which houses all the content of the page? I also tried
> > > atk_state_set_remove_state(stateSetOfPageAtkObject,
> > > ATK_STATE_FOCUSED); but it did not help.
> > >
> > > What should be the correct procedure here? This seems like a generic
> > > problem with any AtkObjects that do not have an actual GtkWidget. I
> > > think I'm doing the above incorrectly.
> > >
> > > Thanks,
> > > Ashutosh
> > > _______________________________________________
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> > > Gnome-accessibility-devel gnome org
> > > http://mail.gnome.org/mailman/listinfo/gnome-accessibility-devel
> > >      
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>
>
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