Re: ProgressBar and error handling

["Paul Davis" <pjdavis engineering uiowa edu>]

On 2/26/07, Sirisha Muppavarapu <sirisha muppavarapu veralight com> wrote:
> Thanks for ur response Paul. Here is more explanation on what I am doing.
>
>  onTimeOut() method is called every 0.5s. Mean while, I do not know when the
> error will happen. If the error happens, I open a new CErrorWindow window
> (Plz note CErrorWindow is not a Dialog, but a subclass derived from window
> and is displayed in place of CProgressBar window. My application design is
> such that I can't use regular dialog window).
>
>  "Is there a reason you're passing the progress bar to the error dialog?"
>
>  Yes, In CErrorWindow, on clicking "Continue" button, I am showing the
> CProgressBar window using the reference passed to CErrorWindow, by calling
>
>  void CErrorWindow :: continueAction() {
>   this->hide();
>   Gtk::Main::run(m_handleToProgressBar);
>   present();
>  }
>
>  What I am trying to achieve here is to get back to the same CProgresBar
> object where I got interrupted and resume from there.
>
>  This is my first ever Gtk app. I am sure, there must be better design out
> there to do the same. Also, I am not using glade to manage my windows.
> Everytime I need to navigate from one window to the other (at the click of a
> button), I do something similar to above or something like
>
>          this->hide();
>          CSomeWindow *some = new CSomeWindow(parameters);
>          Gtk::Main::run(*some);
>          present();
>
>  I am really worried about "N" objects being created and lying there without
> destructor being invoked. Is there a better way of doing all the above
> without using glade?
>
>  Thanks
>  Sirisha
>
>
>
>  -----Original Message-----
>  From: paul joseph davis gmail com on behalf of Paul Davis
>  Sent: Mon 2/26/2007 6:23 PM
>  To: Sirisha Muppavarapu
>  Cc: gtkmm-list gnome org
>  Subject: Re: ProgressBar and error handling
>
>  On 2/26/07, Sirisha Muppavarapu
> <sirisha muppavarapu veralight com> wrote:
>  >
>  >
>  >
>  >
>  > Hi All
>  >
>  >  I have this ProgressBar Window which is running a task and updates
>  > itself(using set_fraction) and it uses signal_timeout()(and onTimeOut()
>  > callback) method. During this backend processing before updating
> itself,if
>  > it encounters an error, it should show another window with the error msg.
> On
>  > clicking continue on the error message, the task should continue its
>  > progress and the progress bar should show progress from where it left.
>  >
>  >  I am able to continue running the task at the back end but how to
> continue
>  > the progress bar's progress from where I left? say it encountered an
> error
>  > at 24% and on clicking continue, the progress should proceed from 24%
>  >
>  >  Any ideas on how to achieve this?
>  >
>  >  Thanks a ton in advance
>  >  Sirisha
>  >
>  >  Code Snippet
>  >  -------------
>  >
>  >  class CProgressBar : public Gtk::Window {
>  >
>  >  public:
>  >  bool onTimeOut();
>  >
>  >  }
>  >
>  >  CProgressBar {
>  >  //someother initializations and logic
>  >  Glib::signal_timeout().connect( sigc::mem_fun(*this,
>  > &CGProgressBar::onTimeout), 500 );
>  >  }
>  >
>  >  bool CProgressBar::onTimeOut() {
>  >
>  >  //update the progress bar using set_fraction
>
>  When you come back into onTimeOut, this logic should figure out where
>  to start from. You can get the current progress bar value with
>  get_fraction() IIRC.
>
>  >  //and wait for error to happen in the backend
>  >
>  >     if(error) {
>  >      this->hide();
>  >      //pass the CProgressBar reference to CErrorWindow object
>
>  Is there a reason you're passing the progress bar to the error dialog?
>
>
>  >      CErrorWindow *error = new CErrorWindow(*this);
>  >      Gtk::Main::run(*error);
>  >      present();
>  >      return false;
>  >     }
>  >  return true;
>  >  }//end of method
>  >
>  >
>  >
>  >
>  >  int main() {
>  >
>  >  CProgressBar *pg = new CProgressBar();
>  >  Gtk::Main::run(*pg);
>  >  present();
>  >  }
>  >
>  >
>  >  In CErrorWindow, there are 2 button "CONTINUE" and "CANCEL"
>  >
>  >  clicking on continue should take you back to CProgressBar and resume
> from
>  > where it left.
>  >
>  >
>  > _______________________________________________
>  > gtkmm-list mailing list
>  > gtkmm-list gnome org
>  > http://mail.gnome.org/mailman/listinfo/gtkmm-list
>  >
>  >
>
>  You should just be able to call back to onTimeOut unless I'm missing
>  something important.  The progress bar will know what fraction its at,
>  but its your job to tell it how to update, which includes continuing
>  from 25% or what not.
>
>  HTH,
>  Paul Davis

Here's a working example that does what you ask.  I don't understand
why you can't use a dialog.  I did cause I don't really see anyother
way to do such a think.

And recursively calling the main loop seems ungood.  Maybe murray or
someone with more knowledge could shed light on if this will cause
problems or not.

Paul

#include <iostream>

#include <gtkmm.h>

class MainWindow : public Gtk::Window
{
	public:

		MainWindow()
		{
			set_size_request( 400, 30 ) ;
			set_title( "ProgressBar Test" ) ;

			Gtk::HBox*	hbox = Gtk::manage( new Gtk::HBox() ) ;
			hbox->set_border_width( 5 ) ;
			Gtk::Label*	lbl = Gtk::manage( new Gtk::Label( "Status: " ) ) ;

			hbox->pack_start( *lbl, Gtk::PACK_SHRINK ) ;

			_pb = Gtk::manage( new Gtk::ProgressBar() ) ;
			_pb->set_fraction( 0.0 ) ;
			_pb->show() ;
			hbox->pack_start( *_pb, Gtk::PACK_EXPAND_WIDGET ) ;

			add( *hbox ) ;

			Glib::signal_timeout().connect( sigc::mem_fun( *this, &MainWindow::updateProgressBar ), 250 ) ;
			_error_shown = false ;

			show_all_children() ;
		}

		bool
		updateProgressBar()
		{
			std::cerr << "Timeout" << std::endl ;

			if( !_error_shown && _pb->get_fraction() > 0.8 )
			{
				_error_shown = true ;
				Gtk::MessageDialog d( *this, "This is an error dialog.", false, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true ) ;
				d.run() ;
				d.hide() ;
				return true ;
			}
			else if( _pb->get_fraction() >= 1.0 )
			{
				Gtk::MessageDialog d( *this, "Operation finished.", false, Gtk::MESSAGE_INFO, Gtk::BUTTONS_OK, true ) ;
				d.run() ;
				d.hide() ;
				hide() ;

				return false ;
			}
			else
			{
				double frac = _pb->get_fraction() ;
				frac += 0.05 ;
				if( frac >= 1.0 ) frac = 1.0 ;
				_pb->set_fraction( frac ) ;
			}

			return true ;
		}

	private:

		bool				_error_shown ;
		Gtk::ProgressBar*	_pb ;
} ;

int
main( int argc, char* argv[] )
{
	Gtk::Main m( argc, argv ) ;
	MainWindow mw ;
	Gtk::Main::run( mw ) ;
}