Re: HScale on_button_press_event blocking
- From: Robert Pearce <rob bdt-home demon co uk>
- To: gtkmm-list gnome org
- Subject: Re: HScale on_button_press_event blocking
- Date: Wed, 9 May 2007 22:19:19 +0100
On Wed, 9 May 2007, Patrick Schweiger <pschweiger symmetricom com> wrote
On Tue, 2007-05-08 at 20:43 -0400, Jeremy Harmon wrote:
bool seekBar::on_button_press_event(GdkEventButton *event)
m_isSeeking = true;
instead of returning false, try calling the super class' implementations
to get the behavior they implement:
Just in case this seems bizarre or contrary to the documentation, I
think it's worth adding a few comments.
When the GTK / GTKmm documentation says you return false to let other
handlers operate, it refers to the way GTK itself hooks up a "list" of
on-event call-backs. This ties several (possibly user-defined) functions
to one GTK event. Each function can return true to say "I have now
completely dealt with this event", or false to let other callbacks have
However, when you _override_ a GTKmm class's existing handler, you are
effectively replacing that function both in C++ terms and, consequently,
in the GTK callback list. Thus if you want the super-class's
functionality, your replacement virtual method must call its parent's
version. This is normal behaviour for C++ (and other OO languages).
I hope that adds clarity and not confusion!
Rob Pearce http://www.bdt-home.demon.co.uk
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