Re: Newbie: How to program window -> serial code -> window?

[muppet <scott asofyet org>]

On Jul 6, 2005, at 1:31 AM, Tokuyasu, Taku wrote:

> I’m trying to do the following:
>
> Open up a window (Entry) to get filenames
> Close the window, and make a system call to an executable with the  
> above filename arguments
> Open up a different window when the system call finishes (e.g. a  
> dialog box with different options)
> I’m not sure if this is obvious or not.  I tried simply duplicating  
> a code block starting with “use Gtk2 '-init':” and ending with  
> “Gtk2->main;”, with the system call in between, but the first  
> window did not disappear after quit’ing the window, instead hanging  
> around until the second window quit.
The second "use Gtk2 -init" is unnecessary; the initialization only  
does anything the first time.

You don't "quit a window" -- you quit an event loop (referred to as a  
"main loop").  In many of the small examples shown here on the list,  
we set up the window to kill the main loop on the window's  
destruction, like this:

   $window->signal_connect (destroy => sub {Gtk2->main_quit});

That says, "when the window is destroyed, stop the main loop".  The  
destruction of the window is triggered elsewhere, such as by the  
default handler for the window's delete-event.

You must either ->hide or ->destroy a window to remove it from the  
screen.  The first window stays visible because you never told it not  
to be.

A reasonable template would be:


   use Gtk2 -init;
   # assume create_first_dialog is a function that creates a
   # Gtk2::Dialog with the desired action buttons.
   $dialog = create_first_dialog ();
   $response = $dialog->run;
   $dialog->destroy;  # remove the dialog from the screen
   exit 0 if $response ne 'ok';

   @input = `$command`;  # program blocks here while reading input

   $dialog = create_second_dialog (@input);
   $dialog->run;
   $dialog->destroy;


Of course, if you want the ui to remain responsive during the call- 
out so that you can display progress or something like that, you need  
to take other measures.  Look in the FAQ under "how do i keep my UI  
responsive during long file reads?"


--
If I lived in Teletubby Land, the homicide rate would be four.
  -- elysse