<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" xmlns:xi="http://www.w3.org/2001/XInclude" type="guide" style="task" id="treeview_cellrenderertoggle.py" lang="ca">
  <info>
    <title type="text">TreeView with TreeStore (Python)</title>
    <link type="guide" xref="beginner.py#treeview"/>
    <link type="next" xref="widget_drawing.py"/>
    <revision version="0.1" date="2012-06-30" status="draft"/>

    <credit type="author copyright">
      <name>Marta Maria Casetti</name>
      <email its:translate="no">mmcasetti@gmail.com</email>
      <years>2012</years>
    </credit>

    <desc>A TreeView displaying a TreeStore (more complex example, with CellRendererToggle)</desc>
  </info>

  <title>More Complex TreeView with TreeStore</title>
  <media type="image" mime="image/png" src="media/treeview_cellrenderertoggle.png"/>
  <p>This TreeView displays a TreeStore with two columns, one of which is rendered as a toggle.</p>

  <links type="section"/>

  <section id="code">
    <title>Code used to generate this example</title>

    <code mime="text/x-python" style="numbered">from gi.repository import Gtk
from gi.repository import Pango
import sys

books = [["Tolstoy, Leo", ["War and Peace", True], ["Anna Karenina", False]],
         ["Shakespeare, William", ["Hamlet", False],
             ["Macbeth", True], ["Othello", False]],
         ["Tolkien, J.R.R.", ["The Lord of the Rings", False]]]


class MyWindow(Gtk.ApplicationWindow):

    def __init__(self, app):
        Gtk.Window.__init__(self, title="Library", application=app)
        self.set_default_size(250, 100)
        self.set_border_width(10)

        # the data are stored in the model
        # create a treestore with two columns
        self.store = Gtk.TreeStore(str, bool)
        # fill in the model
        for i in range(len(books)):
            # the iter piter is returned when appending the author in the first column
            # and False in the second
            piter = self.store.append(None, [books[i][0], False])
            # append the books and the associated boolean value as children of
            # the author
            j = 1
            while j &lt; len(books[i]):
                self.store.append(piter, books[i][j])
                j += 1

        # the treeview shows the model
        # create a treeview on the model self.store
        view = Gtk.TreeView()
        view.set_model(self.store)

        # the cellrenderer for the first column - text
        renderer_books = Gtk.CellRendererText()
        # the first column is created
        column_books = Gtk.TreeViewColumn("Books", renderer_books, text=0)
        # and it is appended to the treeview
        view.append_column(column_books)

        # the cellrenderer for the second column - boolean rendered as a toggle
        renderer_in_out = Gtk.CellRendererToggle()
        # the second column is created
        column_in_out = Gtk.TreeViewColumn("Out?", renderer_in_out, active=1)
        # and it is appended to the treeview
        view.append_column(column_in_out)
        # connect the cellrenderertoggle with a callback function
        renderer_in_out.connect("toggled", self.on_toggled)

        # add the treeview to the window
        self.add(view)

    # callback function for the signal emitted by the cellrenderertoggle
    def on_toggled(self, widget, path):
        # the boolean value of the selected row
        current_value = self.store[path][1]
        # change the boolean value of the selected row in the model
        self.store[path][1] = not current_value
        # new current value!
        current_value = not current_value
        # if length of the path is 1 (that is, if we are selecting an author)
        if len(path) == 1:
            # get the iter associated with the path
            piter = self.store.get_iter(path)
            # get the iter associated with its first child
            citer = self.store.iter_children(piter)
            # while there are children, change the state of their boolean value
            # to the value of the author
            while citer is not None:
                self.store[citer][1] = current_value
                citer = self.store.iter_next(citer)
        # if the length of the path is not 1 (that is, if we are selecting a
        # book)
        elif len(path) != 1:
            # get the first child of the parent of the book (the first book of
            # the author)
            citer = self.store.get_iter(path)
            piter = self.store.iter_parent(citer)
            citer = self.store.iter_children(piter)
            # check if all the children are selected
            all_selected = True
            while citer is not None:
                if self.store[citer][1] == False:
                    all_selected = False
                    break
                citer = self.store.iter_next(citer)
            # if they do, the author as well is selected; otherwise it is not
            self.store[piter][1] = all_selected


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)
</code>
  </section>

  <section id="methods">
    <title>Useful methods for a TreeView widget</title>
    <p>The TreeView widget is designed around a <em>Model/View/Controller</em> design: the <em>Model</em> stores the data; the <em>View</em> gets change notifications and displays the content of the model; the <em>Controller</em>, 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 TreeModel see <link xref="model-view-controller.py"/>.</p>
    <p>In line 48 the <code>"toggled"</code> signal is connected to the callback function <code>on_toggled()</code> using <code><var>widget</var>.connect(<var>signal</var>, <var>callback function</var>)</code>. See <link xref="signals-callbacks.py"/> for a more detailed explanation.</p>
  </section>

  <section id="references">
    <title>API References</title>
    <p>In this sample we used the following:</p>
    <list>
      <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkTreeView.html">GtkTreeView</link></p></item>
      <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkTreeModel.html">GtkTreeModel</link></p></item>
      <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkTreeStore.html">GtkTreeStore</link></p></item>
      <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkCellRendererText.html">GtkCellRendererText</link></p></item>
      <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkCellRendererToggle.html">GtkCellRendererToggle</link></p></item>
      <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkTreeViewColumn.html">GtkTreeViewColumn</link></p></item>
    </list>
  </section>
</page>
