Vstupní pole (Entry)

8.2.1. Jednoduché použití

Vstupní pole umožňují uživateli zadat text. Obsah pole můžete měnit pomocí metody set_text() a aktuální obsah číst pomocí metody get_text().

Příležitostně můžete potřebovat, aby byl widget Entry jen ke čtení. Toho se dá dosáhnout předáním false metodě set_editable().

Pro zadávání hesel, heslových frází a jiných citlivých informací, u kterých nechcete, aby se při psaní zobrazovaly, zavolejte metodu set_visibility() s parametrem false, což způsobí skrytí textu.

You might want to be notified whenever the user types in a text entry widget. Gtk::Entry provides two signals, activate and changed, for 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. Moving the keyboard focus to another widget may also signal that the user has finished entering text. The focus_out_event signal that Gtk::Entry inherits from Gtk::Widget can notify you when that happens. The ComboBox with an Entry section contains example programs that use these signals.

If you pass true to the set_activates_default() method, pressing Enter in the Gtk::Entry will activate the default widget for the window containing the Gtk::Entry. This is especially useful in dialog boxes. The default widget is usually one of the dialog buttons, which e.g. will close the dialog box. To set a widget as the default widget, use Gtk::Widget::set_can_default() and Gtk::Widget::grab_default().

Reference

8.2.1.1. Příklad s jednoduchým vstupním polem

Tento příklad používá Gtk::Entry. Má také dvě zaškrtávací políčka CheckButton, kterými můžete přepínat příznaky editovatelnosti a viditelnosti.

Obrázek 8-2Vstupní pole (Entry)

Source Code

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

#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::Box m_HBox;
  Gtk::Box m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Button m_Button_Close;
  Gtk::CheckButton m_CheckButton_Editable, m_CheckButton_Visible;
};

#endif //GTKMM_EXAMPLEWINDOW_H

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);
}

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

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

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

  set_child(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_Entry.set_expand(true);
  m_VBox.append(m_Entry);

  m_VBox.append(m_HBox);

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

  m_HBox.append(m_CheckButton_Visible);
  m_CheckButton_Visible.set_expand(true);
  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.append(m_Button_Close);
  m_Button_Close.set_expand();
  set_default_widget(m_Button_Close);
}

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();
}

8.2.2. Doplňování vstupu

An 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 an EntryCompletion object, and provide it to the Entry widget via the set_completion() method.

Pomocí metody set_model() můžete pro EntryCompletion určit TreeModel, který bude obsahovat možné vstupy. Pak byste měli ještě zavolat set_text_column() k určení sloupce ve vašem modelu, který se má používat k porovnávání možných textových vstupů.

Případně, když by seznam možných vstupů byl příliš dlouhý, nebo je nevhodné jej přímo vygenerovat, můžete místo toho použít zpětné volání, které zadáte pomocí set_match_func(). Hodí se to také, když potřebujete porovnávat jinou část řetězce, než začátek.

Reference

8.2.2.1. Příklad doplňování vstupu

Tento příklad vytvoří Gtk::EntryCompletion a přidruží jej k widgetu Gtk::Entry. Doplňování využívá Gtk::TreeModel s možnými vstupy a některé doplňující činnosti.

Obrázek 8-3Doplňování vstupu

Source Code

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

#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();

  //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;

  //Child widgets:
  Gtk::Box m_HBox;
  Gtk::Box m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Label m_Label;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H

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);
}

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

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

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

  set_child(m_VBox);
  m_VBox.append(m_Entry);

  m_VBox.append(m_Label);
  m_Label.set_expand(true);

  m_Button_Close.signal_clicked().connect( sigc::mem_fun(*this,
              &ExampleWindow::on_button_close) );
  m_VBox.append(m_Button_Close);
  set_default_widget(m_Button_Close);

  //Add an EntryCompletion:
  auto completion =
      Gtk::EntryCompletion::create();
  m_Entry.set_completion(completion);

  //Create and fill the completion's filter model
  auto 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
  auto 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);
}

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)
  {
    const auto row = *iter;

    const auto key_length = key.size();
    auto filter_string = row[m_Columns.m_col_name];

    auto 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.
}
*/

8.2.3. Ikony ve vstupním poli

Widget Entry umí na začátku a konci textové oblasti zobrazovat ikonu. Ikona se dá určit metodami jako jsou set_icon_from_pixbuf() nebo set_icon_from_icon_name(). Aplikace může reagovat na uživatelovo zmáčknutí ikony obsluhou signálu signal_icon_press.

8.2.3.1. Příklad vstupního pole s ikonami

Tento příklad ukazuje widget Gtk::Entry s pojmenovanou vyhledávací ikonou, při jejímž zmáčknutí vypíše text do terminálu.

Obrázek 8-4Vstupní pole s ikonou

Source Code

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

#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::Entry::IconPosition icon_pos);
  void on_button_close();

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

#endif //GTKMM_EXAMPLEWINDOW_H

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);
}

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

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

ExampleWindow::ExampleWindow()
: m_VBox(Gtk::Orientation::VERTICAL),
  m_Button_Close("Close")
{
  set_title("Gtk::Entry");

  set_child(m_VBox);

  m_Entry.set_max_length(50);
  m_Entry.set_text("Hello world");
  m_VBox.append(m_Entry);

  m_Entry.set_icon_from_icon_name("edit-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.append(m_Button_Close);
  set_default_widget(m_Button_Close);
}

ExampleWindow::~ExampleWindow()
{
}

void ExampleWindow::on_icon_pressed(Gtk::Entry::IconPosition /* icon_pos */)
{
  std::cout << "Icon pressed." << std::endl;
}

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

8.2.4. Vstupní pole s ukazatelem průběhu

Widget Entry umí zobrazovat ukazatel průběhu uvnitř textové oblasti, pod zadávaným textem. Ukazatel průběhu se zobrazí, když je zavolána metoda set_progress_fraction() nebo set_progress_pulse_step().

8.2.4.1. Příklad ukazatele průběhu ve vstupním poli

Tento příklad ukazuje widget Gtk::Entry s ukazatelem průběhu.

Obrázek 8-5Vstupní pole s ukazatelem průběhu

Source Code

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

#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::Box m_VBox;
  Gtk::Entry m_Entry;
  Gtk::Button m_Button_Close;
};

#endif //GTKMM_EXAMPLEWINDOW_H

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);
}

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

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

ExampleWindow::ExampleWindow()
: m_VBox(Gtk::Orientation::VERTICAL),
  m_Button_Close("Close")
{
  set_title("Gtk::Entry");

  set_child(m_VBox);

  m_Entry.set_max_length(50);
  m_Entry.set_text("Hello world");
  m_VBox.append(m_Entry);

  //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.append(m_Button_Close);
  set_default_widget(m_Button_Close);
}

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();
}