Entry

Entry
	Chapter 6. Miscellaneous Widgets

Simple Use

Entry widgets allow the user to enter text. You can change the contents with the set_text() method, and read the current contents with the get_text() method.

Occasionally you might want to make an Entry widget read-only. This can be done by passing false to the set_editable() method.

For the input of passwords, passphrases and other information you don't want echoed on the screen, calling set_visibility() with false will cause the text to be hidden.

You might want to be notified whenever the user types in a text entry widget. Gtk::Entry provides two signals, activate and changed, for just this purpose. activate is emitted when the user presses the enter key in a text-entry widget; changed is emitted when the text in the widget changes. You can use these, for instance, to validate or filter the text the user types.

Reference

Simple Entry Example

This example uses Gtk::Entry. It also has two CheckButtons, with which you can toggle the editable and visible flags.

Figure 6.2. Entry

Source Code

File: examplewindow.h

#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_checkbox_editable_toggled();
  void on_checkbox_visibility_toggled();
  void on_button_close();

  //Child widgets:
  Gtk::HBox m_HBox;
  Gtk::VBox m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Button m_Button_Close;
  Gtk::CheckButton m_CheckButton_Editable, m_CheckButton_Visible;
};

#endif //GTKMM_EXAMPLEWINDOW_H

File: examplewindow.cc

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

ExampleWindow::ExampleWindow()
: m_Button_Close("Close"),
  m_CheckButton_Editable("Editable"),
  m_CheckButton_Visible("Visible")
{
  set_size_request(200, 100);
  set_title("Gtk::Entry");

  add(m_VBox);

  m_Entry.set_max_length(50);
  m_Entry.set_text("hello");
  m_Entry.set_text(m_Entry.get_text() + " world");
  m_Entry.select_region(0, m_Entry.get_text_length());
  m_VBox.pack_start(m_Entry);

  // Note that add() can also be used instead of pack_xxx()
  m_VBox.add(m_HBox);

  m_HBox.pack_start(m_CheckButton_Editable);
  m_CheckButton_Editable.signal_toggled().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_checkbox_editable_toggled) );
  m_CheckButton_Editable.set_active(true);

  m_HBox.pack_start(m_CheckButton_Visible);
  m_CheckButton_Visible.signal_toggled().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_checkbox_visibility_toggled) );
  m_CheckButton_Visible.set_active(true);

  m_Button_Close.signal_clicked().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_button_close) );
  m_VBox.pack_start(m_Button_Close);
  m_Button_Close.set_can_default();
  m_Button_Close.grab_default();

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_checkbox_editable_toggled()
{
  m_Entry.set_editable(m_CheckButton_Editable.get_active());
}

void ExampleWindow::on_checkbox_visibility_toggled()
{
  m_Entry.set_visibility(m_CheckButton_Visible.get_active());
}

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

File: main.cc

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

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

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

  return 0;
}

Entry Completion

A Entry widget can offer a drop-down list of pre-existing choices based on the first few characters typed by the user. For instance, a search dialog could suggest text from previous searches.

To enable this functionality, you must create a EntryCompletion object, and provide it to the Entry widget via the set_completion() method.

The EntryCompletion may use a TreeModel containing possible entries, specified with set_model(). You should then call set_text_column() to specify which of your model columns should be used to match possible text entries.

Alternatively, if a complete list of possible entries would be too large or too inconvenient to generate, a callback slot may instead be specified with set_match_func(). That callback function. This is also useful if you wish to match on a part of the string other than the start.

Reference

Entry Completion Example

This example creates a Gtk::EntryCompletion and associates it with a Gtk::Entry widget. The completion uses a Gtk::TreeModel of possible entries, and some additional actions.

Figure 6.3. Entry Completion

Source Code

File: examplewindow.h

#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_button_close();

  void on_completion_action_activated(int index);

  //See the comment in the implementation:
  //bool on_completion_match(const Glib::ustring& key, const Gtk::TreeModel::const_iterator& iter);


  //Tree model columns, for the EntryCompletion's filter model:
  class ModelColumns : public Gtk::TreeModel::ColumnRecord
  {
  public:

    ModelColumns()
    { add(m_col_id); add(m_col_name); }

    Gtk::TreeModelColumn<unsigned int> m_col_id;
    Gtk::TreeModelColumn<Glib::ustring> m_col_name;
  };

  ModelColumns m_Columns;

  typedef std::map<int, Glib::ustring> type_actions_map;
  type_actions_map m_CompletionActions;
  
  //Child widgets:
  Gtk::HBox m_HBox;
  Gtk::VBox m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Label m_Label;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H

File: examplewindow.cc

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

ExampleWindow::ExampleWindow() :
    m_Label("Press a or b to see a list of possible completions and actions."),
    m_Button_Close("Close")
{
  //set_size_request(200, 100);
  set_title("Gtk::EntryCompletion");

  add(m_VBox);
  m_VBox.pack_start(m_Entry, Gtk::PACK_SHRINK);

  m_VBox.pack_start(m_Label, Gtk::PACK_EXPAND_WIDGET);

  m_Button_Close.signal_clicked().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_button_close) );
  m_VBox.pack_start(m_Button_Close, Gtk::PACK_SHRINK);
  m_Button_Close.set_can_default();
  m_Button_Close.grab_default();

  //Add an EntryCompletion:
  Glib::RefPtr<Gtk::EntryCompletion> completion =
      Gtk::EntryCompletion::create();
  m_Entry.set_completion(completion);

  //Create and fill the completion's filter model
  Glib::RefPtr<Gtk::ListStore> refCompletionModel =
      Gtk::ListStore::create(m_Columns);
  completion->set_model(refCompletionModel);

  // For more complex comparisons, use a filter match callback, like this.
  // See the comment below for more details:
  //completion->set_match_func( sigc::mem_fun(*this,
              //&ExampleWindow::on_completion_match) );

  //Fill the TreeView's model
  Gtk::TreeModel::Row row = *(refCompletionModel->append());
  row[m_Columns.m_col_id] = 1;
  row[m_Columns.m_col_name] = "Alan Zebedee";

  row = *(refCompletionModel->append());
  row[m_Columns.m_col_id] = 2;
  row[m_Columns.m_col_name] = "Adrian Boo";

  row = *(refCompletionModel->append());
  row[m_Columns.m_col_id] = 3;
  row[m_Columns.m_col_name] = "Bob McRoberts";

  row = *(refCompletionModel->append());
  row[m_Columns.m_col_id] = 4;
  row[m_Columns.m_col_name] = "Bob McBob";

  //Tell the completion what model column to use to
  //- look for a match (when we use the default matching, instead of
  //  set_match_func().
  //- display text in the entry when a match is found.
  completion->set_text_column(m_Columns.m_col_name);

  //Add actions to the completion:
  //These are just extra items shown at the bottom of the list of possible
  //completions.

  //Remember them for later.
  m_CompletionActions[0] = "Use Wizard";
  m_CompletionActions[1] = "Browse for Filename";

  for(type_actions_map::iterator iter = m_CompletionActions.begin();
          iter != m_CompletionActions.end(); ++iter)
  {
    int position = iter->first;
    Glib::ustring title = iter->second;
    completion->insert_action_text(title, position);
  }

  completion->signal_action_activated().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_completion_action_activated) );

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

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

/* You can do more complex matching with a handler like this.
 * For instance, you could check for substrings inside the string instead of the start,
 * or you could look for the key in extra model columns as well as the model column that will be displayed.
 * The code here is not actually more complex - it's a reimplementation of the default behaviour.
 *
bool ExampleWindow::on_completion_match(const Glib::ustring& key, const
        Gtk::TreeModel::const_iterator& iter)
{
  if(iter)
  {
    Gtk::TreeModel::Row row = *iter;

    Glib::ustring::size_type key_length = key.size();
    Glib::ustring filter_string = row[m_Columns.m_col_name];

    Glib::ustring filter_string_start = filter_string.substr(0, key_length);
    //The key is lower-case, even if the user input is not.
    filter_string_start = filter_string_start.lowercase();

    if(key == filter_string_start)
      return true; //A match was found.
  }

  return false; //No match.
}
*/

void ExampleWindow::on_completion_action_activated(int index)
{
  type_actions_map::iterator iter = m_CompletionActions.find(index);
  if(iter != m_CompletionActions.end()) //If it's in the map
  {
    Glib::ustring title = iter->second;
    std::cout << "Action selected: " << title << std::endl;
  }
}

File: main.cc

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

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

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

  return 0;
}

Entry Icons

An Entry widget can show an icon at the start or end of the text area. The icon can be specifed by methods such as set_icon_from_pixbuf() or set_icon_from_stock(). An application can respond to the user pressing the icon by handling the signal_icon_press signal.

Entry Icon Example

This example shows a Gtk::Entry widget with a stock search icon, and prints text to the terminal when the icon is pressed.

Figure 6.4. Entry with Icon

Source Code

File: examplewindow.h

#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_icon_pressed(Gtk::EntryIconPosition icon_pos, const GdkEventButton* event);
  void on_button_close();

  //Child widgets:
  Gtk::VBox m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H

File: examplewindow.cc

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

ExampleWindow::ExampleWindow()
: m_Button_Close("Close")
{
  set_title("Gtk::Entry");

  add(m_VBox);

  m_Entry.set_max_length(50);
  m_Entry.set_text("Hello world");
  m_VBox.pack_start(m_Entry, Gtk::PACK_SHRINK);

  m_Entry.set_icon_from_stock(Gtk::Stock::FIND);
  m_Entry.signal_icon_press().connect( sigc::mem_fun(*this, &ExampleWindow::on_icon_pressed) );
 

  m_Button_Close.signal_clicked().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_button_close) );
  m_VBox.pack_start(m_Button_Close, Gtk::PACK_SHRINK);
  m_Button_Close.set_can_default();
  m_Button_Close.grab_default();

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_icon_pressed(Gtk::EntryIconPosition /* icon_pos */, const GdkEventButton* /* event */)
{
  std::cout << "Icon pressed." << std::endl;
}

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

File: main.cc

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

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

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

  return 0;
}

Entry Progress

An Entry widget can show a progress bar inside the text area, under the entered text. The progress bar will be shown if the set_progress_fraction() or set_progress_pulse_step() methods are called.

Entry Progress Example

This example shows a Gtk::Entry widget with a progress bar.

Figure 6.5. Entry with Progress Bar

Source Code

File: examplewindow.h

#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H

#include <gtkmm.h>

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

protected:
  //Signal handlers:
  bool on_timeout();
  void on_button_close();

  //Child widgets:
  Gtk::VBox m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H

File: examplewindow.cc

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

ExampleWindow::ExampleWindow()
: m_Button_Close("Close")
{
  set_title("Gtk::Entry");

  add(m_VBox);

  m_Entry.set_max_length(50);
  m_Entry.set_text("Hello world");
  m_VBox.pack_start(m_Entry, Gtk::PACK_SHRINK);

  //Change the progress fraction every 0.1 second:
  Glib::signal_timeout().connect(
    sigc::mem_fun(*this, &ExampleWindow::on_timeout), 
    100
  );

  m_Button_Close.signal_clicked().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_button_close) );
  m_VBox.pack_start(m_Button_Close, Gtk::PACK_SHRINK);
  m_Button_Close.set_can_default();
  m_Button_Close.grab_default();

  show_all_children();
}

ExampleWindow::~ExampleWindow()
{
}

bool ExampleWindow::on_timeout()
{
  static double fraction = 0;
  m_Entry.set_progress_fraction(fraction);

  fraction += 0.01;
  if(fraction > 1)
    fraction = 0;

  return true;
}

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

File: main.cc

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

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

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

  return 0;
}