<?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="spinner.py" xml:lang="el">
  <info>
    <title type="text">Μετρητής (Python)</title>
    <link type="guide" xref="beginner.py#display-widgets"/>
    <link type="next" xref="progressbar.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>Κίνηση μετρητή</desc>
  
    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
      <mal:name>Ελληνική μεταφραστική ομάδα GNOME</mal:name>
      <mal:email>team@gnome.gr</mal:email>
      <mal:years>2012-2015</mal:years>
    </mal:credit>
  
    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
      <mal:name>Δημήτρης Σπίγγος</mal:name>
      <mal:email>dmtrs32@gmail.com</mal:email>
      <mal:years>2012, 2013</mal:years>
    </mal:credit>
  
    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
      <mal:name>Μαρία Θουκιδίδου</mal:name>
      <mal:email>marablack3@gmail.com</mal:email>
      <mal:years>2014</mal:years>
    </mal:credit>
  
    <mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
      <mal:name>Θάνος Τρυφωνίδης</mal:name>
      <mal:email>tomtryf@gmail.com</mal:email>
      <mal:years>2014, 2015</mal:years>
    </mal:credit>
  </info>

  <title>Μετρητής</title>
  <media type="image" mime="image/png" src="media/spinner.png"/>
  <p>Αυτός ο μετρητής σταματά και ξεκινά πατώντας το πλήκτρο διαστήματος.</p>

  <links type="section"/>

  <section id="code">
  <title>Ο χρησιμοποιούμενος κώδικας για παραγωγή αυτού παραδείγματος</title>

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


class MyWindow(Gtk.ApplicationWindow):
    # a window

    def __init__(self, app):
        Gtk.Window.__init__(self, title="Spinner Example", application=app)
        self.set_default_size(200, 200)
        self.set_border_width(30)

        # a spinner
        self.spinner = Gtk.Spinner()
        # that by default spins
        self.spinner.start()
        # add the spinner to the window
        self.add(self.spinner)

    # event handler
    # a signal from the keyboard (space) controls if the spinner stops/starts
    def do_key_press_event(self, event):
        # keyname is the symbolic name of the key value given by the event
        keyname = Gdk.keyval_name(event.keyval)
        # if it is "space"
        if keyname == "space":
            # and the spinner is active
            if self.spinner.get_property("active"):
                # stop the spinner
                self.spinner.stop()
            # if the spinner is not active
            else:
                # start it again
                self.spinner.start()
        # stop the signal emission
        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)
</code>

  <note><p>
    <code>Gdk.keyval_name(event.keyval)</code> converts the key value <code>event.keyval</code> into a symbolic name. The names and corresponding key values can be found <link href="https://gitlab.gnome.org/GNOME/gtk/blob/master/gdk/gdkkeysyms.h">here</link>, but for instance <code>GDK_KEY_BackSpace</code> becomes the string <code>"BackSpace"</code>.
  </p></note>
  </section>

  <section id="references">
  <title>Αναφορές API</title>
  <p>Σε αυτό το παράδειγμα χρησιμοποιήσαμε τα παρακάτω:</p>
  <list>
    <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkSpinner.html">GtkSpinner</link></p></item>
    <item><p><link href="http://developer.gnome.org/gdk/stable/gdk-Keyboard-Handling.html">Key Values</link></p></item>
  </list>
  </section>
</page>
