Glade3 Python Gtk Tutorial

Part 6b

Gtk ComboBox

The Python Side

Gtk ComboBox

The Gtk ComboBox is a bit complicated to use at first until you understand the related components needed.

Gtk ListStore

First we create an instance of the ListStore. The ListStore will have two columns with the first one being an integer and the second one a string. There are more complicated ways to do this but I like the KISS method.

self.liststore = gtk.ListStore(int,str)

Next we append our data to the ListStore. Each time we are adding two items the first is an integer for the row and the second is the text we want displayed on that row. The items we append to the ListStore in the form of a python list as indicated

self.liststore.append([0,"Select an Item:"])
self.liststore.append([1,"Row 1"])
self.liststore.append([2,"Row 2"])
self.liststore.append([3,"Row 3"])
self.liststore.append([4,"Row 4"])
self.liststore.append([5,"Row 5"])

Building the ComboBox

First we get an instance of our ComboBox which has the name combobox1 from the builder.

self.combobox = self.builder.get_object("combobox1")

Next we set the ListStore as the Model of the ComboBox

self.combobox.set_model(self.liststore)

Next we create an instance of the Gtk CellRendererText object. And using that and a little magic I think we pack the Gtk CellRendererText into the combobox. The only thing I know about line three is the number indicates what column is displayed and the first column is 0.

self.cell = gtk.CellRendererText()
self.combobox.pack_start(self.cell, True)
self.combobox.add_attribute(self.cell, 'text', 1)

And last we set the active row for the combobox. When this happens it also triggers the on_combobox1_changed event.

self.combobox.set_active(0)

ComboBox Changed

The following code is executed when ever the combobox is changed. When the Handler is called it is passed the name of the widget. We use this to be able to change things.

def on_combobox1_changed(self, widget, data=None):
  # get the index of the changed row
  self.index = widget.get_active()

  # get the model
  self.model = widget.get_model()

  # retrieve the item from column 1
  self.item = self.model[self.index][1]

  # debuggin print statements
  print "ComboBox Active Text is", self.item
  print "ComboBox Active Index is", self.index

  # set the text of the label to match the selected item
  self.builder.get_object("label1").set_text(self.item)

The Python Code

glade6.py

#!/usr/bin/env python

try:
  import pygtk
  pygtk.require('2.0')
except:
  pass
try:
  import gtk
  import gtk.glade
except:
  print('GTK not available')
  sys.exit(1)

class Buglump:

  def __init__(self):
    self.builder = gtk.Builder()
    self.builder.add_from_file("glade6.glade")
    self.builder.connect_signals(self)

    # the liststore
    self.liststore = gtk.ListStore(int,str)
    self.liststore.append([0,"Select an Item:"])
    self.liststore.append([1,"Row 1"])
    self.liststore.append([2,"Row 2"])
    self.liststore.append([3,"Row 3"])
    self.liststore.append([4,"Row 4"])
    self.liststore.append([5,"Row 5"])

    # the combobox
    self.combobox = self.builder.get_object("combobox1")
    self.combobox.set_model(self.liststore)
    self.cell = gtk.CellRendererText()
    self.combobox.pack_start(self.cell, True)
    self.combobox.add_attribute(self.cell, 'text', 1)
    self.combobox.set_active(0)

    self.window = self.builder.get_object("window1")
    self.window.show()

  def on_combobox1_changed(self, widget, data=None):
    self.index = widget.get_active()
    self.model = widget.get_model()
    self.item = self.model[self.index][1]
    print "ComboBox Active Text is", self.item
    print "ComboBox Active Index is", self.index
    self.builder.get_object("label1").set_text(self.item)

  def on_window1_destroy(self, object, data=None):
    print "quit with cancel"
    gtk.main_quit()

if __name__ == "__main__":
  main = Buglump()
  gtk.main()

Run the App

Open a terminal and change directory to the directory where your files are. Type in ls to see a list of the files. Type in chmod +x glade6.py to make the glade6.py file executable. Now to run the app type in ./glade6.py.

Figure 1. Terminal Commands

When you first start the application the on_combobox1_changed is ran because of the line self.combobox.set_active(0)

Figure 2. Glade6 Tutorial

After selecting an item from the ComboBox the item text is mirrored in the label.

Figure 3. ComboBox Item Selected

the zipped python file

Next up is using a sqlite database to populate the ComboBox.