<?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="switch.js" lang="sv">
  <info>
  <title type="text">Switch (Javascript)</title>
    <link type="guide" xref="beginner.js#buttons"/>
    <revision version="0.1" date="2012-06-18" status="draft"/>

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

    <desc>A sliding switch that can be flipped on and off</desc>
  <credit type="translator copyright"><name>Sebastian Rasmussen</name><email>sebras@gmail.com</email><years>2019</years></credit><credit type="translator copyright"><name>Anders Jonsson</name><email>anders.jonsson@norsjovallen.se</email><years>2021</years></credit></info>

  <title>Switch</title>
  <media type="image" mime="image/png" src="media/switchanimals.png"/>
  <p>En Switch har två lägen, på och av. Detta exempel visar hur du kan använda flera brytare tillsammans för att styra vilken <link xref="image.js">Image</link> som visas i fönstret. Bilderna som används i detta exempel <link href="https://live.gnome.org/TarynFox?action=AttachFile&amp;do=get&amp;target=Animal+Photos.zip">kan hämtas här</link>.</p>
  <note><p>Fönstret kommer innehålla en ”trasig bild”-ikon istället för en bild om bildfiler med namnen <file>redfox.png</file>, <file>muteswan.png</file>, <file>fruitbat.png</file> och <file>gentoopenguin.png</file> inte finns i samma katalog. Du kan ändra koderna och bilderna som du vill, men de Creative Commons-licensierade fotona som används i detta exempel togs från följande källor och beskars till 640x425:</p>
    <list>
        <item><p><link href="http://en.wikipedia.org/wiki/File:Fuzzy_Freddy.jpg">Foto av röd räv</link> av Rob Lee, licensierat <link href="http://creativecommons.org/licenses/by/2.0/deed.en">CC-By</link></p></item>
        <item><p><link href="http://en.wikipedia.org/wiki/File:Pygoscelis_papua_-Nagasaki_Penguin_Aquarium_-swimming_underwater-8a.jpg">Foto av åsnepingvin</link> av Ken Funakoshi, licensierat <link href="http://creativecommons.org/licenses/by-sa/2.0/deed.en">CC-By-SA</link></p></item>
        <item><p><link href="http://www.flickr.com/photos/shekgraham/127431519/in/photostream/">Foto av flyghund</link> av Shek Graham, licensierat <link href="http://creativecommons.org/licenses/by/2.0/deed.en">CC-By</link></p></item>
        <item><p><link href="http://commons.wikimedia.org/wiki/File:Mute_Swan-Mindaugas_Urbonas.jpg">Foto av knölsvan</link> av Mindaugas Urbonas, licensierat <link href="http://creativecommons.org/licenses/by-sa/2.5/deed.en">CC-By-SA</link></p></item>
    </list>
    <p>Photo credits and licensing information are shown in the application's <link xref="aboutdialog.js">AboutDialog</link>. Always remember to credit the original artist when using <link href="http://creativecommons.org">Creative Commons-licensed works!</link></p></note>
    <links type="section"/>

  <section id="imports">
    <title>Bibliotek att importera</title>
    <code mime="application/javascript">
#!/usr/bin/gjs

const Gio = imports.gi.Gio;
const Gtk = imports.gi.Gtk;
const Lang = imports.lang;
</code>
    <p>Detta är biblioteken som vi behöver importera för att detta program ska köras. Kom ihåg att raden som säger till GNOME att vi använder Gjs alltid behöver vara först.</p>
    </section>

  <section id="applicationwindow">
    <title>Skapa programfönstret</title>
    <code mime="application/javascript">
const SwitchExample = new Lang.Class({
    Name: 'Switch-exempel',

    // Skapa programmet i sig
    _init: function() {
        this.application = new Gtk.Application({
            application_id: 'org.example.jsswitch',
            flags: Gio.ApplicationFlags.FLAGS_NONE
        });

    // Anslut ”activate”- och ”startup”-signaler till återanropsfunktionerna
    this.application.connect('activate', Lang.bind(this, this._onActivate));
    this.application.connect('startup', Lang.bind(this, this._onStartup));
    },

    // Återanropsfunktion för ”activate”-signal, visar fönstret när den aktiveras
    _onActivate: function() {
        this._window.present();
    },

    // Återanropsfunktion för ”startup”-signal skapar menyn och bygger användargränssnittet
    _onStartup: function() {
        this._initMenus();
        this._buildUI ();
    },
</code>
    <p>All kod för detta exempel hamnar i klassen SwitchExample. Koden ovan skapar en <link href="http://www.roojs.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.Application.html">Gtk.Application</link> att ha våra komponenter och fönstret i.</p>
    <note><p>Before we call _buildUI to create the window and the widgets inside it, we need to call _initMenus, which tells GNOME to create the menu. We can put the actual code for _initMenus after the code for _buildUI, since it doesn't matter what order we put them in so long as _initMenus is called first in _onStartup.</p></note>
    <code mime="application/javascript">
    // Bygg programmets användargränssnitt
    _buildUI: function() {

        // Skapa programfönstret
        this._window = new Gtk.ApplicationWindow({
            application: this.application,
            window_position: Gtk.WindowPosition.CENTER,
            border_width: 20,
            title: "Djurskapare"});
</code>
    <p>_buildUI-funktionen är var vi stoppar all kod för att skapa programmets användargränssnitt. Det första steget är att skapa ett nytt <link xref="GtkApplicationWindow.js">Gtk.ApplicationWindow</link> att stoppa alla våra komponenter i.</p>
  </section>

  <section id="button">
    <title>Skapa brytarna</title>
    <code mime="application/javascript">
        // Skapa bildkomponenten och ställ in dess standardbild
        this._image = new Gtk.Image ({file: "redfox.png"});
</code>

    <p>Vi skapar först den <link xref="image.js">Image</link> som brytarna kommer styra. Kom ihåg att en fil med namnet <file>redfox.png</file> behöver finnas i samma katalog som detta program.</p>

    <code mime="application/javascript">
        // Skapa en etikett för den första brytaren
        this._flyLabel = new Gtk.Label ({
            label: "Få den att flyga",
            margin_right: 30});

        // Skapa den första brytaren och ställ in dess standardposition
        this._flySwitch = new Gtk.Switch ({active: false});
        this._flySwitch.connect ('notify::active', Lang.bind (this, this._switchFlip));

        // Skapa en etikett för den andra brytaren
        this._birdLabel = new Gtk.Label ({
            label: "Gör den till en fågel",
            margin_right: 30});

        // Skapa den andra brytaren
        this._birdSwitch = new Gtk.Switch ({active: false});
        this._birdSwitch.connect ('notify::active', Lang.bind (this, this._switchFlip));
</code>

    <p>Vi använder en <link xref="label.js">Label</link> för att märka varje Switch, och ger dem lite marginal till höger så de inte är ihopträngda just intill Switcharna. Efter det skapar vi Switcharna, och ställer in dem att vara avstängda som standard.</p>
    <p>Signalen som en brytare sänder ut när den slås på eller av kallas för notify::active. Efter att vi skapar varje brytare ansluter vi dess notify::active-signal till en funktion som kallas _switchFlip. Om du har flera brytare som gör olika saker, så kan du vilja ansluta dem till olika funktioner, men här används de båda för samma sak: att styra vilken bild som visas av _image.</p>

    <code mime="application/javascript">
        // Skapa ett rutnät för etiketterna och brytarna under bilden
        this._UIGrid = new Gtk.Grid ({
            halign: Gtk.Align.CENTER,
            valign: Gtk.Align.CENTER,
            margin_top: 20});

        // Fäst etiketterna och brytarna vid det rutnätet
        this._UIGrid.attach (this._flyLabel, 0, 0, 1, 1);
        this._UIGrid.attach (this._flySwitch, 1, 0, 1, 1);
        this._UIGrid.attach (this._birdLabel, 0, 1, 1, 1);
        this._UIGrid.attach (this._birdSwitch, 1, 1, 1, 1);

        // Skapa ett huvudrutnät att stoppa både användargränssnittet och bilden i
        this._mainGrid = new Gtk.Grid ({
            halign: Gtk.Align.CENTER,
            valign: Gtk.Align.CENTER });

        // Fäst bilden och användargränssnittsrutnätet vid huvudrutnätet
        this._mainGrid.attach (this._image, 0, 0, 1, 1);
        this._mainGrid.attach (this._UIGrid, 0, 1, 1, 1);
</code>
    <p>We create a <link xref="grid.js">Grid</link> for the Labels and Switches first, so that we can organize them in a 2x2 layout with a margin between it and the Image. Then we put that Grid into a larger 2x1 Grid that has the Image on top, and the Grid with the Labels and Switches on the bottom.</p>
    <code mime="application/javascript">
        // Lägg till huvudrutnätet till fönstret
        this._window.add (this._mainGrid);

        // Visa fönstret och alla barnkomponenter
        this._window.show_all();
    },
</code>
    <p>Slutligen lägger vi till vår större Grid till fönstret, och säger sedan till fönstret att visa sig själv och alla komponenterna i det.</p>
    </section>

    <section id="switch-handler">
    <title>Funktion som hanterar att brytarna ändrar tillstånd</title>

    <code mime="application/javascript">
    _switchFlip: function() {

        // Ändra bilden beroende på vilka brytare som ändrar tillstånd
        if (this._flySwitch.get_active()) {

            if (this._birdSwitch.get_active()) this._image.set_from_file ("muteswan.png");

            else this._image.set_from_file ("fruitbat.png");
        }

        else {

            if (this._birdSwitch.get_active()) this._image.set_from_file ("gentoopenguin.png");

            else this._image.set_from_file ("redfox.png");

        }

    },
</code>
    <p>Each time a Switch is flipped, this function checks to see which of the two Switches are active afterwards, using the Switches' built-in get_active() function. It then changes the Image accordingly. You can change the filenames around as you like, so long as you have pictures to go with them.</p>
</section>

<section id="about">
    <title>Skapa AboutDialog</title>
    <code mime="application/javascript">
    _initMenus: function() {

        // Build the application's menu so we can have an "About" button
        let menu = new Gio.Menu();
        menu.append("About", 'app.about');
        menu.append("Quit",'app.quit');
        this.application.set_app_menu(menu);

        // Bind the "About" button to the _showAbout() function
        let aboutAction = new Gio.SimpleAction ({ name: 'about' });
        aboutAction.connect('activate', Lang.bind(this,
            function() {
                this._showAbout();
            }));
        this.application.add_action(aboutAction);

        // Bind the "Quit" button to the function that closes the window
        let quitAction = new Gio.SimpleAction ({ name: 'quit' });
        quitAction.connect('activate', Lang.bind(this,
            function() {
                this._window.destroy();
            }));
        this.application.add_action(quitAction);
    },
</code>
    <p>The first step is building the <link xref="gmenu.js">GMenu</link> that the "About" button goes into. This is the menu that appears when you click the application's name in the upper-left corner of the screen, next to the Activities menu. Our menu only has two options in it: About, and Quit.</p>

    <code mime="application/javascript">
    _showAbout: function () {

        // String arrays of the names of the people involved in the project
        var artists = ['Rob Lee http://en.wikipedia.org/wiki/File:Fuzzy_Freddy.jpg', 'Ken Funakoshi http://en.wikipedia.org/wiki/File:Pygoscelis_papua_-Nagasaki_Penguin_Aquarium_-swimming_underwater-8a.jpg', 'Shek Graham http://www.flickr.com/photos/shekgraham/127431519/in/photostream/', 'Mindaugas Urbonas http://commons.wikimedia.org/wiki/File:Mute_Swan-Mindaugas_Urbonas.jpg'];
        var authors = ["GNOME Documentation Team"];
        var documenters = ["GNOME Documentation Team"];

        // Create the About dialog
        let aboutDialog = new Gtk.AboutDialog({
            title: "AboutDialog Example",
            program_name: "Animal Creator",
            copyright: "Copyright \xa9 2012 GNOME Documentation Team\n\nRed fox photo licensed CC-By by Rob Lee\nGentoo penguin photo licensed CC-By-SA by Ken Funakoshi\nFruit bat photo licensed CC-By by Shek Graham\nMute swan photo licensed CC-By-SA by Mindaugas Urbonas\nLinks to the originals are available under Credits.\n\nHave you hugged a penguin today?",
            artists: artists,
            authors: authors,
            documenters: documenters,
            website: "http://developer.gnome.org",
            website_label: "GNOME Developer Website" });

        // Attach the About dialog to the window
        aboutDialog.modal = true;
        aboutDialog.transient_for = this._window;

        // Show the About dialog
        aboutDialog.show();

        // Connect the Close button to the destroy signal for the dialog
        aboutDialog.connect('response', function() {
            aboutDialog.destroy();
        });
    }

});
</code>
    <p>An <link xref="aboutdialog.js">AboutDialog</link> has a lot of different things you can set, to credit everyone who worked on the application and leave a note to whomever reads it. In this case, the copyright section contains our note and credits the original photographers, while the artists section shows you a list of the photographers with links to the original photos when you click the Credits button. The web URLs put after their names in the array turn their names into clickable links in the Credits section.</p>

    <code mime="application/javascript">
// Kör programmet
let app = new SwitchExample ();
app.application.run (ARGV);
</code>
    <p>Slutligen skapar vi en ny instans av den slutförda SwitchExample-klassen, och startar programmet.</p>
  </section>

  <section id="complete">
    <title>Fullständigt kodexempel</title>
<code mime="application/javascript" style="numbered">#!/usr/bin/gjs

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

const Gio = imports.gi.Gio;
const Gtk = imports.gi.Gtk;

class SwitchExample {

    // Create the application itself
    constructor() {
        this.application = new Gtk.Application({
            application_id: 'org.example.jsswitch'
        });

        // 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 window when active
    _onActivate() {
        this._window.present();
    }

    // Callback function for 'startup' signal creates the menu and builds the UI
    _onStartup() {
        this._initMenus();
        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,
            border_width: 20,
            title: "Animal Creator"});

        // Create the image widget and set its default picture
        this._image = new Gtk.Image ({file: "redfox.png"});

        // Create a label for the first switch
        this._flyLabel = new Gtk.Label ({
            label: "Make it fly",
            margin_right: 30});

        // Create the first switch and set its default position
        this._flySwitch = new Gtk.Switch ({active: false});
        this._flySwitch.connect ('notify::active', this._switchFlip.bind(this));

        // Create a label for the second switch
        this._birdLabel = new Gtk.Label ({
            label: "Make it a bird",
            margin_right: 30});

        // Create the second switch
        this._birdSwitch = new Gtk.Switch ({active: false});
        this._birdSwitch.connect ('notify::active', this._switchFlip.bind(this));

        // Create a grid for the labels and switches beneath the picture
        this._UIGrid = new Gtk.Grid ({
            halign: Gtk.Align.CENTER,
            valign: Gtk.Align.CENTER,
            margin_top: 20});

        // Attach the labels and switches to that grid
        this._UIGrid.attach (this._flyLabel, 0, 0, 1, 1);
        this._UIGrid.attach (this._flySwitch, 1, 0, 1, 1);
        this._UIGrid.attach (this._birdLabel, 0, 1, 1, 1);
        this._UIGrid.attach (this._birdSwitch, 1, 1, 1, 1);

        // Create a master grid to put both the UI and the picture into
        this._mainGrid = new Gtk.Grid ({
            halign: Gtk.Align.CENTER,
            valign: Gtk.Align.CENTER });

        // Attach the picture and the UI grid to the master grid
        this._mainGrid.attach (this._image, 0, 0, 1, 1);
        this._mainGrid.attach (this._UIGrid, 0, 1, 1, 1);

        // Add the master grid to the window
        this._window.add (this._mainGrid);

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

    _switchFlip() {

        // Change the picture depending on which switches are flipped
        if (this._flySwitch.get_active()) {

            if (this._birdSwitch.get_active())
                this._image.set_from_file ("muteswan.png");
            else
                this._image.set_from_file ("fruitbat.png");
        } else {

            if (this._birdSwitch.get_active())
                this._image.set_from_file ("gentoopenguin.png");
            else
                this._image.set_from_file ("redfox.png");
        }
    }

    _initMenus() {

        // Build the application's menu so we can have an "About" button
        let menu = new Gio.Menu();
        menu.append("About", 'app.about');
        menu.append("Quit",'app.quit');
        this.application.set_app_menu(menu);

        // Bind the "About" button to the _showAbout() function
        let aboutAction = new Gio.SimpleAction ({ name: 'about' });
        aboutAction.connect('activate', () =&gt; { this._showAbout(); });
        this.application.add_action(aboutAction);

        // Bind the "Quit" button to the function that closes the window
        let quitAction = new Gio.SimpleAction ({ name: 'quit' });
        quitAction.connect('activate', () =&gt; { this._window.destroy(); });
        this.application.add_action(quitAction);
    }

    _showAbout() {

        // String arrays of the names of the people involved in the project
        var artists = ['Rob Lee http://en.wikipedia.org/wiki/File:Fuzzy_Freddy.png', 'Ken Funakoshi http://en.wikipedia.org/wiki/File:Pygoscelis_papua_-Nagasaki_Penguin_Aquarium_-swimming_underwater-8a.png', 'Shek Graham http://www.flickr.com/photos/shekgraham/127431519/in/photostream/', 'Mindaugas Urbonas http://commons.wikimedia.org/wiki/File:Mute_Swan-Mindaugas_Urbonas.png'];
        var authors = ["GNOME Documentation Team"];
        var documenters = ["GNOME Documentation Team"];

        // Create the About dialog
        let aboutDialog = new Gtk.AboutDialog({
            title: "AboutDialog Example",
            program_name: "Animal Creator",
            copyright: "Copyright \xa9 2012 GNOME Documentation Team\n\nRed fox photo licensed CC-By by Rob Lee\nGentoo penguin photo licensed CC-By-SA by Ken Funakoshi\nFruit bat photo licensed CC-By by Shek Graham\nMute swan photo licensed CC-By-SA by Mindaugas Urbonas\nLinks to the originals are available under Credits.\n\nHave you hugged a penguin today?",
            artists: artists,
            authors: authors,
            documenters: documenters,
            website: "http://developer.gnome.org",
            website_label: "GNOME Developer Website" });

        // Attach the About dialog to the window
        aboutDialog.modal = true;
        aboutDialog.transient_for = this._window;

        // Show the About dialog
        aboutDialog.show();

        // Connect the Close button to the destroy signal for the dialog
        aboutDialog.connect('response', function() {
            aboutDialog.destroy();
        });
    }
};

// Run the application
let app = new SwitchExample ();
app.application.run (ARGV);
</code>
  </section>

  <section id="in-depth">
    <title>Djupgående dokumentation</title>
<list>
  <item><p><link href="http://developer.gnome.org/gio/unstable/GMenu.html">GMenu</link></p></item>
  <item><p><link href="http://developer.gnome.org/gio/stable/GSimpleAction.html">GSimpleAction</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.org/seed/gir-1.2-gtk-3.0/gjs/Gtk.Grid.html">Gtk.Grid</link></p></item>
  <item><p><link href="http://www.roojs.org/seed/gir-1.2-gtk-3.0/gjs/Gtk.Image.html">Gtk.Image</link></p></item>
  <item><p><link href="http://www.roojs.org/seed/gir-1.2-gtk-3.0/gjs/Gtk.Label.html">Gtk.Label</link></p></item>
  <item><p><link href="http://www.roojs.org/seed/gir-1.2-gtk-3.0/gjs/Gtk.Switch.html">Gtk.Switch</link></p></item>
</list>
  </section>
</page>
