InfoBar

#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_infobar_response(int response);
  void on_button_quit();
  void on_button_clear();
  void on_textbuffer_changed();

  //Child widgets:
  Gtk::Box m_VBox;

  Gtk::ScrolledWindow m_ScrolledWindow;
  Gtk::TextView m_TextView;
  
  Glib::RefPtr<Gtk::TextBuffer> m_refTextBuffer;

  Gtk::InfoBar m_InfoBar;
  Gtk::Label m_Message_Label;

  Gtk::ButtonBox m_ButtonBox;
  Gtk::Button m_Button_Quit, m_Button_Clear;
};

#endif //GTKMM_EXAMPLEWINDOW_H

#include "examplewindow.h"

ExampleWindow::ExampleWindow()
: m_VBox(Gtk::ORIENTATION_VERTICAL, 6),
  m_Button_Quit("_Quit", true),
  m_Button_Clear("_Clear", true)
{
  set_title("Gtk::InfoBar example");
  set_border_width(6);
  set_default_size(400, 200);

  add(m_VBox);

  // Add the message label to the InfoBar:
  Gtk::Container* infoBarContainer =
    dynamic_cast<Gtk::Container*>(m_InfoBar.get_content_area());
  if (infoBarContainer)
    infoBarContainer->add(m_Message_Label);

  // Add an ok button to the InfoBar:
  m_InfoBar.add_button("_OK", 0);

  // Add the InfoBar to the vbox:
  m_VBox.pack_start(m_InfoBar, Gtk::PACK_SHRINK);

  // Create the buffer and set it for the TextView:
  m_refTextBuffer = Gtk::TextBuffer::create();
  m_TextView.set_buffer(m_refTextBuffer);

  // Add the TreeView, inside a ScrolledWindow:
  m_ScrolledWindow.add(m_TextView);

  // Show the scrollbars only when they are necessary:
  m_ScrolledWindow.set_policy(Gtk::POLICY_AUTOMATIC, Gtk::POLICY_AUTOMATIC);

  m_VBox.pack_start(m_ScrolledWindow);

  // Add button box:
  m_VBox.pack_start(m_ButtonBox, Gtk::PACK_SHRINK);

  m_ButtonBox.pack_start(m_Button_Clear, Gtk::PACK_SHRINK);
  m_ButtonBox.pack_start(m_Button_Quit, Gtk::PACK_SHRINK);
  m_ButtonBox.set_spacing(6);
  m_ButtonBox.set_layout(Gtk::BUTTONBOX_END);

  // Connect signals:
  m_InfoBar.signal_response().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_infobar_response) );
  m_Button_Quit.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_button_quit) );
  m_Button_Clear.signal_clicked().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_button_clear) );
  m_refTextBuffer->signal_changed().connect(sigc::mem_fun(*this,
              &ExampleWindow::on_textbuffer_changed) );

  show_all();

  // Keep the InfoBar hidden until a message needs to be shown:
  m_InfoBar.hide();

  // Make the clear button insensitive until text is typed in the buffer.  When
  // the button is sensitive and it is pressed, the InfoBar is displayed with a
  // message.
  m_Button_Clear.set_sensitive(false);
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_infobar_response(int)
{
  // Clear the message and hide the info bar:
  m_Message_Label.set_text("");
  m_InfoBar.hide();
}

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

void ExampleWindow::on_button_clear()
{
  m_refTextBuffer->set_text("");
  m_Message_Label.set_text("Cleared the text.");
  m_InfoBar.set_message_type(Gtk::MESSAGE_INFO);
  m_InfoBar.show();
}

void ExampleWindow::on_textbuffer_changed()
{
  m_Button_Clear.set_sensitive(m_refTextBuffer->size() > 0);
}

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

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

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