Besides indicating the amount of progress that has occured, the progress bar can also be used to indicate that there is some activity; this is done by placing the progress bar in activity mode. In this mode, the progress bar displays a small rectangle which moves back and forth. Activity mode is useful in situations where the progress of an operation cannot be calculated as a value range (e.g., receiving a file of unknown length).

To do this, you need to call the pulse() method at regular intervals. You can also choose the step size, with the set_pulse_step() method.

The progress bar can also display a configurable text string within its trough, using the set_text() method.

Source Code

File: examplewindow.h (For use with gtkmm 3, not gtkmm 2)

#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include <gtkmm.h>

class ExampleWindow : public Gtk::Window
{
public:
  ExampleWindow();
  virtual ~ExampleWindow();

protected:
  //Signal handlers:
  void on_checkbutton_text();
  void on_checkbutton_activity();
  void on_checkbutton_inverted();

  bool on_timeout();
  void on_button_close();

  //Child widgets:
  Gtk::Box m_VBox;
  Gtk::Grid m_Grid;
  Gtk::ProgressBar m_ProgressBar;
  Gtk::Separator m_Separator;
  Gtk::CheckButton m_CheckButton_Text, m_CheckButton_Activity, m_CheckButton_Inverted;
  Gtk::Button m_Button_Close;

  sigc::connection m_connection_timeout;
  bool m_bActivityMode;
};

#endif //GTKMM_EXAMPLEWINDOW_H

File: main.cc (For use with gtkmm 3, not gtkmm 2)

#include "examplewindow.h"
#include <gtkmm/application.h>

int main(int argc, char *argv[])
{
  auto app = Gtk::Application::create(argc, argv, "org.gtkmm.example");

  ExampleWindow window;

  //Shows the window and returns when it is closed.
  return app->run(window);
}

File: examplewindow.cc (For use with gtkmm 3, not gtkmm 2)

#include "examplewindow.h"
#include <iostream>

ExampleWindow::ExampleWindow()
: m_VBox(Gtk::ORIENTATION_VERTICAL, 5),
  m_CheckButton_Text("Show text"),
  m_CheckButton_Activity("Activity mode"),
  m_CheckButton_Inverted("Right to Left"),
  m_Button_Close("Close"),
  m_bActivityMode(false)
{
  set_resizable();
  set_title("Gtk::ProgressBar");

  m_VBox.set_border_width(10);
  add(m_VBox);

  m_VBox.pack_start(m_ProgressBar, Gtk::PACK_SHRINK, 5);
  m_ProgressBar.set_halign(Gtk::ALIGN_CENTER);
  m_ProgressBar.set_valign(Gtk::ALIGN_CENTER);
  m_ProgressBar.set_text("some text");
  m_ProgressBar.set_show_text(false);

  //Add a timer callback to update the value of the progress bar:
  m_connection_timeout = Glib::signal_timeout().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_timeout), 50 );

  m_VBox.pack_start(m_Separator, Gtk::PACK_SHRINK);
  m_VBox.pack_start(m_Grid);
  m_Grid.set_row_homogeneous(true);

  //Add a check button to select displaying of the trough text:
  m_Grid.attach(m_CheckButton_Text, 0, 0, 1, 1);
  m_CheckButton_Text.property_margin() = 5;
  m_CheckButton_Text.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_checkbutton_text) );

  //Add a check button to toggle activity mode:
  m_Grid.attach(m_CheckButton_Activity, 0, 1, 1, 1);
  m_CheckButton_Activity.property_margin() = 5;
  m_CheckButton_Activity.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_checkbutton_activity) );

  //Add a check button to select growth from left to right or from right to left:
  m_Grid.attach(m_CheckButton_Inverted, 0, 2, 1, 1);
  m_CheckButton_Inverted.property_margin() = 5;
  m_CheckButton_Inverted.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_checkbutton_inverted) );

  //Add a button to exit the program.
  m_VBox.pack_start(m_Button_Close, Gtk::PACK_SHRINK);
  m_Button_Close.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_button_close) );
  m_Button_Close.set_can_default();
  m_Button_Close.grab_default();

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_checkbutton_text()
{
  const bool show_text = m_CheckButton_Text.get_active();
  m_ProgressBar.set_show_text(show_text);
}

void ExampleWindow::on_checkbutton_activity()
{
  m_bActivityMode = m_CheckButton_Activity.get_active();

  if(m_bActivityMode)
    m_ProgressBar.pulse();
  else
    m_ProgressBar.set_fraction(0.0);
}

void ExampleWindow::on_checkbutton_inverted()
{
  const bool inverted = m_CheckButton_Inverted.get_active();
  m_ProgressBar.set_inverted(inverted);
}

void ExampleWindow::on_button_close()
{
  hide();
}

/* Update the value of the progress bar so that we get
 * some movement */
bool ExampleWindow::on_timeout()
{
  if(m_bActivityMode)
    m_ProgressBar.pulse();
  else
  {
    double new_val = m_ProgressBar.get_fraction() + 0.01;

    if(new_val > 1.0)
      new_val = 0.0;

    //Set the new value:
    m_ProgressBar.set_fraction(new_val);
  }

  //As this is a timeout function, return true so that it
  //continues to get called
  return true;
}