<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="switch.py" xml:lang="gl">

  <info>

    <title type="text">Switch (Python)</title>

    <link type="guide" xref="beginner.py#buttons"/>

    <link type="next" xref="radiobutton.py"/>

    <revision version="0.1" date="2012-05-24" 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 "light switch" style toggle</desc>

    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">

      <mal:name>Fran Dieguez</mal:name>

      <mal:email>frandieguez@gnome.org</mal:email>

      <mal:years>2012-2013.</mal:years>

    </mal:credit>

  </info>

  <title>Interruptor</title>

  <media type="image" mime="image/png" style="floatend" src="media/switch_off.png"/>

  <media type="image" mime="image/png" src="media/switch_on.png"/>

  
This Switch makes the title appears and disappear.

  <links type="section"/>

  <section id="code">

    <title>Código usado para xerar este exemplo</title>

    from gi.repository import Gtk

import sys

class MyWindow(Gtk.ApplicationWindow):

    # a window

    def __init__(self, app):

        Gtk.Window.__init__(self, title="Switch Example", application=app)

        self.set_default_size(300, 100)

        self.set_border_width(10)

        # a switch

        switch = Gtk.Switch()

        # turned on by default

        switch.set_active(True)

        # connect the signal notify::active emitted by the switch

        # to the callback function activate_cb

        switch.connect("notify::active", self.activate_cb)

        # a label

        label = Gtk.Label()

        label.set_text("Title")

        # a grid to allocate the widgets

        grid = Gtk.Grid()

        grid.set_column_spacing(10)

        grid.attach(label, 0, 0, 1, 1)

        grid.attach(switch, 1, 0, 1, 1)

        # add the grid to the window

        self.add(grid)

    # Callback function. Since the signal is notify::active

    # we need the argument 'active'

    def activate_cb(self, button, active):

        # if the button (i.e. the switch) is active, set the title

        # of the window to "Switch Example"

        if button.get_active():

            self.set_title("Switch Example")

        # else, set it to "" (empty string)

        else:

            self.set_title("")

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)

  </section>

  <section id="methods">

    <title>Useful methods for a Switch widget</title>

    
In line 17 the signal "notify::active" is connected to the callback function activate_cb() using widget.connect(signal, callback function). See <link xref="signals-callbacks.py"/> for a more detailed explanation.

  </section>

  <section id="references">

    <title>API References</title>

    
Neste exemplo empregaremos o seguinte:

    <list>

      <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkSwitch.html">GtkSwitch</link>
</item>

      <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkLabel.html">GtkLabel</link>
</item>

      <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkGrid.html">GtkGrid</link>
</item>

    </list>

  </section>

</page>