<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="de">

  <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>

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

      <mal:name>Mario Blättermann</mal:name>

      <mal:email>mario.blaettermann@gmail.com</mal:email>

      <mal:years>2011, 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.

#!/usr/bin/gjs

imports.gi.versions.Gtk = '3.0';

const Gio = imports.gi.Gio;

const GLib = imports.gi.GLib;

const Gtk = imports.gi.Gtk;

class ProgressBarExample {

    // Create the application itself

    constructor() {

        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', this._onActivate.bind(this));

        this.application.connect('startup', this._onStartup.bind(this));

    }

    // Callback function for 'activate' signal presents windows when active

    _onActivate() {

        this._window.present();

    }

    // Callback function for 'startup' signal builds the UI

    _onStartup() {

        this._buildUI();

    }

    // Build the application's UI

    _buildUI() {

        // 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,

                                         this._barPulse.bind(this));

        // Connect a keypress event to the function that toggles the bar to start or stop pulsing

        this._window.connect("key-press-event", this._onKeyPress.bind(this));

            // Show the window and all child widgets

            this._window.show_all();

    }

    // Pulse the progressbar (unless it has been disabled by a keypress)

    _barPulse() {

        this.progressBar.pulse();

        return true;

    }

    // Start or stop the progressbar when a key is pressed

    _onKeyPress() {

        if (this.sourceID == 0)

            this.sourceID = GLib.timeout_add(GLib.PRIORITY_DEFAULT, 100,

                                             this._barPulse.bind(this));

        else {

            GLib.source_remove(this.sourceID);

            this.sourceID = 0;

        }

    }

};

// Run the application

let app = new ProgressBarExample ();

app.application.run (ARGV);

  In this sample we used the following:

<list>

  <item>
<link href="http://www.roojs.org/seed/gir-1.2-gtk-3.0/gjs/GLib.html">GLib</link>
</item>

  <item>
<link href="http://www.roojs.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.Application.html">Gtk.Application</link>
</item>

  <item>
<link href="http://developer.gnome.org/gtk3/stable/GtkApplicationWindow.html">Gtk.ApplicationWindow</link>
</item>

    <item>
<link href="http://www.roojs.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.ProgressBar.html">Gtk.ProgressBar</link>
</item>

</list>

</page>