Re: GTK app with no keyboard/mouse

["Brian J. Tarricone" <bjt23 cornell edu>]

Mike Rosenlof wrote:

> This system will have a display, and a remote control device.  I'm
> planning on a separate thread from the GUI which receives the remote
> codes, interprets them, and injects appropriate events into the GUI.
>
> Let's assume for the moment that the remote has just six buttons.  Menu,
> up, down, left, right, select.  Any thoughts on the best way to inject
> events?  So far I have found that a "move-focus" signal on the window
> containing a bunch of button and slider widgets is not the answer (for
> direction navigation).  Neither does gtk_window_propagate_key_event()
> seem to be what I want.  I, of course, want to use the GTK
> infrastructure instead of rolling my own.  Any suggestions?
As another poster mentioned, I too have had problems using 
gdk_event_put() to synthesize events.  What has worked for me is using 
XSendEvent(), passing it the window of the target widget.  You need to 
call it twice, for ButtonPress and ButtonRelease.  If you're just doing 
button presses, I believe you can use gtk_button_clicked()[1] instead.  
There are probably other similar functions you can call for other 
widgets that are "clickable" in the sense of activating them; the API 
docs will help here.  Note that GtkButton is a subclass for a bunch of 
different button types (like GtkCheckButton), so gtk_button_click() will 
work for all of them.

For widget navigation, I'd suggest using a state machine.  So you keep 
track of which widget has focus, and create a state table for the 
transitions, so you basically have a list of starting widgets, and for 
each of the four arrow directions, you have a widget to move to.  Then 
just use gdk_widget_grab_focus() to make the change.

   -brian

[1] 
http://developer.gnome.org/doc/API/2.0/gtk/GtkButton.html#gtk-button-clicked