<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="progressbar.py" xml:lang="pt-BR">

  <info>

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

    <link type="guide" xref="beginner.py#display-widgets"/>

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

    <revision version="0.2" date="2012-06-12" 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 widget which indicates progress visually.</desc>

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

      <mal:name>Rafael Ferreira</mal:name>

      <mal:email>rafael.f.f1@gmail.com</mal:email>

      <mal:years>2013</mal:years>

    </mal:credit>

  </info>

  <title>ProgressBar</title>

  <media type="video" mime="application/ogv" src="media/progressbar.ogv">

    <tt:tt xmlns:tt="http://www.w3.org/ns/ttml">

      <tt:body>

        <tt:div begin="0s" end="6s">

          <tt:p>

              Pressing any key stops and starts this ProgressBar.

          </tt:p>

        </tt:div>

      </tt:body>

    </tt:tt>

  </media>

  
This ProgressBar is stopped and started by pressing any key.

  <links type="section"/>

  <section id="code">

  <title>Code used to generate this example</title>

  from gi.repository import GLib

from gi.repository import Gtk

import sys

class MyWindow(Gtk.ApplicationWindow):

    # a window

    def __init__(self, app):

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

        self.set_default_size(220, 20)

        # a progressbar

        self.progress_bar = Gtk.ProgressBar()

        # add the progressbar to the window

        self.add(self.progress_bar)

        # the method self.pulse is called each 100 milliseconds

        # and self.source_id is set to be the ID of the event source

        # (i.e. the bar changes position every 100 milliseconds)

        self.source_id = GLib.timeout_add(100, self.pulse)

    # event handler

    # any signal from the keyboard controls if the progressbar stops/starts

    def do_key_press_event(self, event):

        # if the progressbar has been stopped (therefore source_id == 0 - see

        # "else" below), turn it back on

        if (self.source_id == 0):

            self.source_id = GLib.timeout_add(100, self.pulse)

        # if the bar is moving, remove the source with the ID of source_id

        # from the main context (stop the bar) and set the source_id to 0

        else:

            GLib.source_remove(self.source_id)

            self.source_id = 0

        # stop the signal emission

        return True

    # source function

    # the progressbar is in "activity mode" when this method is called

    def pulse(self):

        self.progress_bar.pulse()

        # call the function again

        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)

  </section>

  <section id="methods">

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

  <list>

    <item>
Instead of pulse(), that makes the bar go back and forth, if we want the ProgressBar to "fill in" a fraction (a float between 0.0 and 1.0 included) of the bar that has been completed, use set_fraction(fraction).
</item>

    <item>
To set a text and show it (superimposed over the bar) use set_text("text") and set_show_text(True). If a text is not set and set_show_text(True) the text will be the percentage of the work that has been completed.
</item>

  </list>

  </section>

  <section id="references">

  <title>API References</title>

  
In this sample we used the following:

  <list>

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

    <item>
<link href="http://developer.gnome.org/glib/stable/glib-The-Main-Event-Loop.html">GLib - The Main Event Loop</link>
</item>

    <item>
<link href="http://developer.gnome.org/gdk/stable/gdk-Keyboard-Handling">Gdk - Key Values</link>
</item>

  </list>

  </section>

</page>