Gtk::Main and Gtk::Window

Two Basic Elements

• Gtk::Main
• Every application must have one of these objects.
• It cannot be global and must be the first Gtk object created.
• It is a singleton.
• Pass in app arguments in main()
• Use Gtk::Main::quit() to exit from the application
• Gtk::Window
• Top level window.
• Controlled by the window manager
• Hidden when window manager's close button is clicked.

Example: Hello World!

main.cc:

#include <gtkmm/main.h>
#include "helloworld.h"

int main (int argc, char *argv[])
{
  Gtk::Main kit(argc, argv);

  HelloWorld helloworld;
  Gtk::Main::run(helloworld); //Shows the window and returns when it is closed.

  return 0;
}

helloworld.h:

#ifndef GTKMM_EXAMPLE_HELLOWORLD_H
#define GTKMM_EXAMPLE_HELLOWORLD_H

#include <gtkmm/button.h>
#include <gtkmm/window.h>

class HelloWorld : public Gtk::Window
{

public:
  HelloWorld();
  virtual ~HelloWorld();

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

  //Member widgets:
  Gtk::Button m_button;
};

#endif // GTKMM_EXAMPLE_HELLOWORLD_H

helloworld.cc:

#include "helloworld.h"

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

HelloWorld::HelloWorld()
: m_button("Hello World")   // creates a new button with the label "Hello World".
{
  // Sets the border width of the window.
  set_border_width(10);

  // When the button receives the "clicked" signal, it will call the
  // on_button_clicked() method. The on_button_clicked() method is defined below.
  m_button.signal_clicked().connect(sigc::mem_fun(*this, &HelloWorld::on_button_clicked));

  // This packs the button into the Window (a container).
  add(m_button);

  // The final step is to display this newly created widget...
  m_button.show();
}

HelloWorld::~HelloWorld()
{
}

void HelloWorld::on_button_clicked()
{
  std::cout << "Hello World" << std::endl;
}