Chapter 15. Dialogs

Table of Contents

Dialogs are used as secondary windows, to provide specific information or to ask questions. Gtk::Dialog windows contain a few pre-packed widgets to ensure consistency, and a run() method which blocks until the user dismisses the dialog.

There are several derived Dialog classes which you might find useful. Gtk::MessageDialog is used for most simple notifications. But at other times you might need to derive your own dialog class to provide more complex functionality.

To pack widgets into a custom dialog, you should pack them into the Gtk::Box, available via get_content_area(). To just add a Button to the bottom of the Dialog, you could use the add_button() method.

The run() method returns an int. This may be a value from the Gtk::ResponseType if the user closed the dialog by clicking a standard button, or it could be the custom response value that you specified when using add_button().

Reference

MessageDialog

MessageDialog is a convenience class, used to create simple, standard message dialogs, with a message, an icon, and buttons for user response. You can specify the type of message and the text in the constructor, as well as specifying standard buttons via the Gtk::ButtonsType enum.

Reference

Example

Figure 15.1. MessageDialog

MessageDialog

Source Code

File: examplewindow.h (For use with gtkmm 4)

#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include <gtkmm.h>
#include <memory>

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

protected:
  //Signal handlers:
  void on_button_info_clicked();
  void on_button_question_clicked();
  void on_question_dialog_response(int response_id);

  //Child widgets:
  Gtk::Box m_ButtonBox;
  Gtk::Button m_Button_Info, m_Button_Question;

  std::unique_ptr<Gtk::MessageDialog> m_pDialog;
};

#endif //GTKMM_EXAMPLEWINDOW_H

File: examplewindow.cc (For use with gtkmm 4)

#include "examplewindow.h"
#include <gtkmm/messagedialog.h>
#include <iostream>


ExampleWindow::ExampleWindow()
: m_ButtonBox(Gtk::Orientation::VERTICAL),
  m_Button_Info("Show Info MessageDialog"),
  m_Button_Question("Show Question MessageDialog")
{
  set_title("Gtk::MessageDialog example");

  set_child(m_ButtonBox);

  m_ButtonBox.append(m_Button_Info);
  m_Button_Info.set_expand(true);
  m_Button_Info.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_button_info_clicked) );

  m_ButtonBox.append(m_Button_Question);
  m_Button_Question.set_expand(true);
  m_Button_Question.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_button_question_clicked) );
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_button_info_clicked()
{
  m_pDialog.reset(new Gtk::MessageDialog(*this, "This is an INFO MessageDialog"));
  m_pDialog->set_secondary_text(
          "And this is the secondary text that explains things.");
  m_pDialog->set_modal(true);
  m_pDialog->set_hide_on_close(true);
  m_pDialog->signal_response().connect(
    sigc::hide(sigc::mem_fun(*m_pDialog, &Gtk::Widget::hide)));

  m_pDialog->show();
}

void ExampleWindow::on_button_question_clicked()
{
  m_pDialog.reset(new Gtk::MessageDialog(*this, "This is a QUESTION MessageDialog",
          false /* use_markup */, Gtk::MessageType::QUESTION,
          Gtk::ButtonsType::OK_CANCEL, true /* modal */));
  m_pDialog->set_secondary_text(
          "And this is the secondary text that explains things.");
  m_pDialog->set_hide_on_close(true);
  m_pDialog->signal_response().connect(
    sigc::mem_fun(*this, &ExampleWindow::on_question_dialog_response));

  m_pDialog->show();
}

void ExampleWindow::on_question_dialog_response(int response_id)
{
  m_pDialog->hide();

  //Handle the response:
  switch (response_id)
  {
    case Gtk::ResponseType::OK:
    {
      std::cout << "OK clicked." << std::endl;
      break;
    }
    case Gtk::ResponseType::CANCEL:
    {
      std::cout << "Cancel clicked." << std::endl;
      break;
    }
    default:
    {
      std::cout << "Unexpected button clicked." << std::endl;
      break;
    }
  }
}

File: main.cc (For use with gtkmm 4)

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

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

  //Shows the window and returns when it is closed.
  return app->make_window_and_run<ExampleWindow>(argc, argv);
}