<?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="progressbar.js" xml:lang="ca">
  <info>
  <title type="text">ProgressBar (JavaScript)</title>
    <link type="guide" xref="beginner.js#display-widgets"/>
    <revision version="0.1" date="2012-06-01" status="draft"/>

    <credit type="author copyright">
      <name>Taryn Fox</name>
      <email its:translate="no">jewelfox@fursona.net</email>
      <years>2012</years>
    </credit>

    <desc>A bar which animates to indicate progress</desc>
  </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>
  <p>This ProgressBar is stopped and started by pressing any key.</p>

<code mime="application/javascript" style="numbered">#!/usr/bin/gjs

const Gio = imports.gi.Gio;
const GLib = imports.gi.GLib;
const Gtk = imports.gi.Gtk;
const Lang = imports.lang;

const ProgressBarExample = new Lang.Class({
    Name: 'ProgressBar Example',

    // Create the application itself
        _init: function() {
        this.application = new Gtk.Application({
            application_id: 'org.example.jsprogressbar',
            flags: Gio.ApplicationFlags.FLAGS_NONE
        });

    // Connect 'activate' and 'startup' signals to the callback functions
    this.application.connect('activate', Lang.bind(this, this._onActivate));
    this.application.connect('startup', Lang.bind(this, this._onStartup));
    },

    // Callback function for 'activate' signal presents windows when active
    _onActivate: function() {
        this._window.present();
    },

    // Callback function for 'startup' signal builds the UI
    _onStartup: function() {
        this._buildUI ();
    },



    // Build the application's UI
    _buildUI: function() {

        // Create the application window
            this._window = new Gtk.ApplicationWindow({ application: this.application,
                                                       window_position: Gtk.WindowPosition.CENTER,
                                                       default_height: 20,
                                                       default_width: 220,
                                                       title: "ProgressBar Example"});

        // Create the progress bar
        this.progressBar = new Gtk.ProgressBar ();
        this._window.add(this.progressBar);

        // Start the function that pulses the bar every 100 milliseconds
        this.sourceID = GLib.timeout_add(GLib.PRIORITY_DEFAULT, 100, Lang.bind(this, this._barPulse));

        // Connect a keypress event to the function that toggles the bar to start or stop pulsing
        this._window.connect("key-press-event", Lang.bind(this, this._onKeyPress));

            // Show the window and all child widgets
            this._window.show_all();
    },



    // Pulse the progressbar (unless it has been disabled by a keypress)
    _barPulse: function() {
        this.progressBar.pulse();
        return true;
    },

    // Start or stop the progressbar when a key is pressed
    _onKeyPress: function() {
        if (this.sourceID == 0)
            this.sourceID = GLib.timeout_add(GLib.PRIORITY_DEFAULT, 100, Lang.bind(this, this._barPulse));
        else {
            GLib.source_remove(this.sourceID);
            this.sourceID = 0;
        }
    }

});

// Run the application
let app = new ProgressBarExample ();
app.application.run (ARGV);
</code>
<p>
  In this sample we used the following:
</p>
<list>
  <item><p><link href="http://www.roojs.org/seed/gir-1.2-gtk-3.0/gjs/GLib.html">GLib</link></p></item>
  <item><p><link href="http://www.roojs.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.Application.html">Gtk.Application</link></p></item>
  <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkApplicationWindow.html">Gtk.ApplicationWindow</link></p></item>
    <item><p><link href="http://www.roojs.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.ProgressBar.html">Gtk.ProgressBar</link></p></item>
</list>
</page>
