Radio Button

There is no separate class for radio buttons. Check buttons and toggle buttons act as radio buttons when they form a group. Only one button in a group can be selected at any one time.

6.4.1. Groups

You create the buttons, and set up their group afterwards. In the following example, we put 3 radio buttons in a group:

auto rb1 = Gtk::make_managed<Gtk::CheckButton>("button1");
auto rb2 = Gtk::make_managed<Gtk::CheckButton>("button2");
auto rb3 = Gtk::make_managed<Gtk::CheckButton>("button3");
rb2->set_group(*rb1);
rb3->set_group(*rb1);

We told gtkmm to put all three CheckButtons in the same group by using set_group() to tell the other CheckButtons to share group with the first CheckButton.

6.4.2. Methods

CheckButtons and ToggleButtons are "off" when created; this means that when you first make a group of them, they will all be off. Don't forget to turn one of them on using set_active().

Reference

6.4.3. Example

The following example demonstrates the use of grouped CheckButtons:

Figure 6-3RadioButton

Source Code

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

#ifndef GTKMM_EXAMPLE_RADIOBUTTONS_H
#define GTKMM_EXAMPLE_RADIOBUTTONS_H

#include <gtkmm/box.h>
#include <gtkmm/window.h>
#include <gtkmm/button.h>
#include <gtkmm/checkbutton.h>
#include <gtkmm/separator.h>

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

protected:
  //Signal handlers:
  void on_button_clicked();

  //Child widgets:
  Gtk::Box m_Box_Top, m_Box1, m_Box2;
  Gtk::CheckButton m_RadioButton1, m_RadioButton2, m_RadioButton3;
  Gtk::Separator m_Separator;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLE_RADIOBUTTONS_H

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

#include "radiobuttons.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<RadioButtons>(argc, argv);
}

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

#include "radiobuttons.h"

RadioButtons::RadioButtons() :
  m_Box_Top(Gtk::Orientation::VERTICAL),
  m_Box1(Gtk::Orientation::VERTICAL, 10),
  m_Box2(Gtk::Orientation::VERTICAL, 10),
  m_RadioButton1("button1"),
  m_RadioButton2("button2"),
  m_RadioButton3("button3"),
  m_Button_Close("close")
{
  // Set title and border of the window
  set_title("radio buttons");

  // Gtk::CheckButton and Gtk::ToggleButton have set_group() methods.
  // They act as radio buttons, if they are included in a group.

  // Put radio buttons 2 and 3 in the same group as 1:
  m_RadioButton2.set_group(m_RadioButton1);
  m_RadioButton3.set_group(m_RadioButton1);

  // Add outer box to the window (because the window
  // can only contain a single widget)
  set_child(m_Box_Top);

  //Put the inner boxes and the separator in the outer box:
  m_Box_Top.append(m_Box1);
  m_Box_Top.append(m_Separator);
  m_Box_Top.append(m_Box2);
  m_Separator.set_expand();

  // Set the inner boxes' margins
  m_Box1.set_margin(10);
  m_Box2.set_margin(10);

  // Put the radio buttons in Box1:
  m_Box1.append(m_RadioButton1);
  m_Box1.append(m_RadioButton2);
  m_Box1.append(m_RadioButton3);
  m_RadioButton1.set_expand();
  m_RadioButton2.set_expand();
  m_RadioButton3.set_expand();

  // Set the second button active
  m_RadioButton2.set_active(true);

  // Put Close button in Box2:
  m_Box2.append(m_Button_Close);
  m_Button_Close.set_expand();

  // Make the button the default widget
  set_default_widget(m_Button_Close);

  // Connect the toggled signal of the button to
  // RadioButtons::on_button_toggled()
  m_Button_Close.signal_clicked().connect(sigc::mem_fun(*this,
              &RadioButtons::on_button_clicked) );
}

RadioButtons::~RadioButtons()
{
}

void RadioButtons::on_button_clicked()
{
  hide(); //to close the application.
}