Re: How to update the content of a tree view

[Ian Martin <martin_id vodafone co nz>]

On 24/02/13 06:39, John Tall wrote:
> Hello.
>
> I'm familiar with GUI programming but is fairly new to GTK+ and GTKmm.
> I'm going through the basics but is stuck on how to properly design my
> application for use of tree views.
>
> Let's say that I have an application that creates and runs a number of
> "jobs". These jobs are displayed in a tree view where each job has a
> job ID and a progress bar, where the progress bar shows how much of
> the job that is done.
>
>
>
> What is the appropriate way to update a tree view after it has been created?
>
> John
Hi John,
"the appropriate way " is the one that works best - for any definition 
of best :)  .

You have to be a bit careful keeping pointers to a treeview row.  If the 
treeview gets updated at all, their behaviour is not guaranteed.

Had you considered using a signal to connect the widget to it's data?  
You could either use a timeout:

Glib::signal_timeout().connect(sigc::mem_fun(*this, 
&My_Widget::on_Update), 50); //50 msec between automatically running the 
function

or a dedicated function that signals when the job has progressed by a 
minimum amount:

Five_Percent_Change.signal_increment().connect(sigc::bind(sigc::mem_fun
        (*this, &My_Widget::on_Update), New_Value));

Have a look in the sigc documentation at 
http://libsigc.sourceforge.net/libsigc2/docs/manual/html/ch03.html
because there's a bit of work to create a class that emits a signal (as 
opposed to simply receiving one).  However, if you did it like that, you 
can then leave the widget to update based on changes to the underlying data.

Ian.