<?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_advanced_liststore.py" xml:lang="ca">
  <info>
    <title type="text">Simple Treeview with ListStore (Python)</title>
    <link type="guide" xref="beginner.py#treeview"/>
    <link type="next" xref="treeview_cellrenderertoggle.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 ListStore (more complex example)</desc>
  </info>

  <title>More Complex Treeview with ListStore</title>
  <media type="image" mime="image/png" src="media/treeview_advanced_liststore.png"/>
  <p>This TreeView displays a simple ListStore with the selection "changed" signal connected.</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

list_of_dvd = [["The Usual Suspects"],
               ["Gilda"],
               ["The Godfather"],
               ["Pulp Fiction"],
               ["Once Upon a Time in the West"],
               ["Rear Window"]]


class MyWindow(Gtk.ApplicationWindow):

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

        # the data are stored in the model
        # create a liststore with one column
        self.listmodel = Gtk.ListStore(str)
        for i in range(len(list_of_dvd)):
            self.listmodel.append(list_of_dvd[i])

        # a treeview to see the data stored in the model
        view = Gtk.TreeView(model=self.listmodel)

        # cellrenderer for the first column
        cell = Gtk.CellRendererText()
        # the first column is created
        col = Gtk.TreeViewColumn("Title", cell, text=0)
        # and it is appended to the treeview
        view.append_column(col)

        # when a row of the treeview is selected, it emits a signal
        self.selection = view.get_selection()
        self.selection.connect("changed", self.on_changed)

        # the label we use to show the selection
        self.label = Gtk.Label()
        self.label.set_text("")

        # a button to add new titles, connected to a callback function
        self.button_add = Gtk.Button(label="Add")
        self.button_add.connect("clicked", self.add_cb)

        # an entry to enter titles
        self.entry = Gtk.Entry()

        # a button to remove titles, connected to a callback function
        self.button_remove = Gtk.Button(label="Remove")
        self.button_remove.connect("clicked", self.remove_cb)

        # a button to remove all titles, connected to a callback function
        self.button_remove_all = Gtk.Button(label="Remove All")
        self.button_remove_all.connect("clicked", self.remove_all_cb)

        # a grid to attach the widgets
        grid = Gtk.Grid()
        grid.attach(view, 0, 0, 4, 1)
        grid.attach(self.label, 0, 1, 4, 1)
        grid.attach(self.button_add, 0, 2, 1, 1)
        grid.attach_next_to(
            self.entry, self.button_add, Gtk.PositionType.RIGHT, 1, 1)
        grid.attach_next_to(
            self.button_remove, self.entry, Gtk.PositionType.RIGHT, 1, 1)
        grid.attach_next_to(
            self.button_remove_all, self.button_remove, Gtk.PositionType.RIGHT, 1, 1)

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

    def on_changed(self, selection):
        # get the model and the iterator that points at the data in the model
        (model, iter) = selection.get_selected()
        # set the label to a new value depending on the selection, if there is
        # one
        if iter is not None:
            self.label.set_text("\n %s" % (model[iter][0]))
        else:
            self.label.set_text("")
        return True

    # callback function for the "Add" button
    def add_cb(self, button):
        # append to the model the title that is in the entry
        title = self.entry.get_text()
        self.listmodel.append([title])
        # and print a message in the terminal
        print("%s has been added" % (title))

    def remove_cb(self, button):
        # if there is still an entry in the model
        if len(self.listmodel) != 0:
            # get the selection
            (model, iter) = self.selection.get_selected()
            # if there is a selection, print a message in the terminal
            # and remove it from the model
            if iter is not None:
                print("%s has been removed" % (model[iter][0]))
                self.listmodel.remove(iter)
            # otherwise, ask the user to select something to remove
            else:
                print("Select a title to remove")
        # else, if there are no entries in the model, print "Empty list"
        # in the terminal
        else:
            print("Empty list")

    def remove_all_cb(self, button):
        # if there is still an entry in the model
        if len(self.listmodel) != 0:
            # remove all the entries in the model
            for i in range(len(self.listmodel)):
                iter = self.listmodel.get_iter(0)
                self.listmodel.remove(iter)
        # print a message in the terminal alerting that the model is empty
        print("Empty list")


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 36 the <code>"changed"</code> signal is connected to the callback function <code>on_changed()</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/GtkListStore.html">GtkListStore</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/GtkTreeViewColumn.html">GtkTreeViewColumn</link></p></item>
      <item><p><link href="https://gitlab.gnome.org/GNOME/pygobject/blob/master/gi/overrides/Gtk.py">pygobject - Python bindings for GObject Introspection</link></p></item>
    </list>
  </section>
</page>
