# ComboBox (Python)

Marta Maria Casetti
mmcasetti@gmail.com 2012
A widget used to choose from a list of items
Fran Dieguez
frandieguez@gnome.org 2012-2013.

# ComboBox (one column)

This ComboBox prints to the terminal your selection when you change it.

# Código usado para xerar este exemplo

from gi.repository import Gtk import sys

distros = [["Select distribution"], ["Fedora"], ["Mint"], ["Suse"]]

class MyWindow(Gtk.ApplicationWindow):

def __init__(self, app): Gtk.Window.__init__(self, title="Welcome to GNOME", application=app) self.set_default_size(200, -1) self.set_border_width(10)

# the data in the model, of type string listmodel = Gtk.ListStore(str) # append the data in the model for i in range(len(distros)): listmodel.append(distros[i])

# a combobox to see the data stored in the model combobox = Gtk.ComboBox(model=listmodel)

# a cellrenderer to render the text cell = Gtk.CellRendererText()

# pack the cell into the beginning of the combobox, allocating # no more space than needed combobox.pack_start(cell, False) # associate a property ("text") of the cellrenderer (cell) to a column (column 0) # in the model used by the combobox combobox.add_attribute(cell, "text", 0)

# the first row is the active one by default at the beginning combobox.set_active(0)

# connect the signal emitted when a row is selected to the callback # function combobox.connect("changed", self.on_changed)

# add the combobox to the window self.add(combobox)

def on_changed(self, combo): # if the row selected is not the first one, write its value on the # terminal if combo.get_active() != 0: print("You chose " + str(distros[combo.get_active()][0]) + ".") return True

class MyApplication(Gtk.Application):

def __init__(self): Gtk.Application.__init__(self)

def do_activate(self): win = MyWindow(self) win.show_all()

def do_startup(self): Gtk.Application.do_startup(self)

app = MyApplication() exit_status = app.run(sys.argv) sys.exit(exit_status)

# Useful methods for a ComboBox widget

The ComboBox widget is designed around a Model/View/Controller design: the Model stores the data; the View gets change notifications and displays the content of the model; the Controller, finally, changes the state of the model and notifies the view of these changes. For more information and for a list of useful methods for ComboBox see .

In line 35 the `"changed"` signal is connected to the callback function `on_changed()` using `widget.connect(signal, callback function)`. See for a more detailed explanation.

# API References

Neste exemplo empregaremos o seguinte:

GtkComboBox

GtkListStore

GtkCellRendererText

GtkCellLayout

pygobject - Python bindings for GObject Introspection