<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" xmlns:xi="http://www.w3.org/2001/XInclude" type="guide" style="task" id="messagedialog.js" xml:lang="es">
  <info>
  <title type="text">MessageDialog (JavaScript)</title>
    <link type="guide" xref="beginner.js#windows"/>
    <link type="seealso" xref="GtkApplicationWindow.js"/>
    <link type="seealso" xref="gmenu.js"/>
    <link type="seealso" xref="label.js"/>
    <revision version="0.2" date="2012-06-25" status="draft"/>

    <credit type="author copyright">
      <name>Taryn Fox</name>
      <email>jewelfox@fursona.net</email>
      <years>2012</years>
    </credit>

    <desc>Una mensaje emergente acoplado a una ventana</desc>
  </info>

  <title>MessageDialog</title>
  <media type="image" mime="image/png" src="media/messagedialog.png"/>
  <p>A MessageDialog is a modal message dialog, which means a popup that you have to respond to before you get back to what you were doing in the window that it's attached to. This one can cause the world to explode (or at least it says that it can). To make the popup appear when you run this sample, click on "Message" inside of its application menu -- that's the menu that appears when you click on an application's name in the upper-left screen corner, next to Activities.</p>
  <note><p>The difference between a MessageDialog and a <link xref="dialog.js">Dialog</link> is that a Dialog can contain whatever widgets and content you want to put in it, whereas a MessageDialog is just a convenient way to make popups appear with a basic message and buttons.</p></note>
    <links type="section"/>

  <section id="imports">
    <title>Bibliotecas que importar</title>
    <code mime="application/javascript"><![CDATA[
#!/usr/bin/gjs

const Gio = imports.gi.Gio;
const Gtk = imports.gi.Gtk;
const Lang = imports.lang;
]]></code>
    <p>Estas son las bibliotecas que necesita importar para que esta aplicación se ejecute. Recuerde que la línea que le dice a GNOME que está usando Gjs siempre tiene que ir al principio.</p>
  </section>

  <section id="applicationwindow">
    <title>Crear la ventana de la aplicación</title>
    <code mime="application/javascript"><![CDATA[
const MessageDialogExample = new Lang.Class ({
    Name: 'MessageDialog Example',

    // Create the application itself
    _init: function () {
        this.application = new Gtk.Application ({
            application_id: 'org.example.jsmessagedialog',
            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 initializes menus and builds the UI
    _onStartup: function () {
        this._initMenus();
        this._buildUI ();
    },
]]></code>
    <p>All the code for this sample goes in the MessageDialogExample class. The above code creates a <link href="http://www.roojs.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.Application.html">Gtk.Application</link> for our widgets and window to go in.</p>
    <note><p>Antes de llamar a «_buildUI» para crear la ventana y sus widgets, es necesario llamar a «_initMenus», que le dice a GNOME que cree el menú. Se puede poner el código de «_initMenus» después del código de «_buildUI», dado que no importa en qué orden se esté mientras que «_initMenus» se llame primero en «_onStartup».</p></note>
    <code mime="application/javascript"><![CDATA[
    // Build the application's UI
    _buildUI: function () {

        // Create the application window
        this._window = new Gtk.ApplicationWindow  ({
            application: this.application,
            window_position: Gtk.WindowPosition.CENTER,
            title: "Gtk.MessageDialog Example",
            default_height: 200,
            default_width: 400 });
]]></code>
    <p>La función _buildUI es donde se pone todo el código que crea la interfaz de usuario de la aplicación. El primer paso es crear una <link xref="GtkApplicationWindow.js">Gtk.ApplicationWindow</link> nueva para poner dentro todos los widgets.</p>

    <code mime="application/javascript"><![CDATA[
        // Create a silly warning message and add it to the window
        this.warningLabel = new Gtk.Label ({
            label: "This application goes boom! (Not really.)"});
        this._window.add (this.warningLabel);
]]></code>
    <p>For this example, all that we have in the window the popup comes out of is a silly warning <link xref="label.js">Label</link>.</p>
  </section>

  <section id="menu">
    <title>Crear el menú de la aplicación</title>
    <code mime="application/javascript"><![CDATA[
    // Build the application menu, including the button that calls the dialog
    _initMenus: function() {
        let menu = new Gio.Menu();
        menu.append("Message",'app.message');
        menu.append("Quit",'app.quit');
        this.application.set_app_menu(menu);

        // This pops up a MessageDialog when "Message" is clicked in the menu
        let messageAction = new Gio.SimpleAction ({ name: 'message' });
        messageAction.connect('activate', Lang.bind(this,
            function() {
                this._showMessageDialog();
            }));
        this.application.add_action(messageAction);

        // This closes the window when "Quit" is clicked in the menu
        let quitAction = new Gio.SimpleAction ({ name: 'quit' });
        quitAction.connect('activate', Lang.bind(this,
            function() {
                this._window.destroy();
            }));
        this.application.add_action(quitAction);
    },
]]></code>
    <p>Here, we build the <link xref="gmenu.js">GMenu</link> where we'll be putting the "Message" button which triggers the popup MessageDialog. The GMenu 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: Message, and Quit.</p>
  </section>

  <section id="messagedialog">
    <title>Crear el «MessageDialog»</title>
    <code mime="application/javascript"><![CDATA[
    _showMessageDialog: function () {

        // Create a modal MessageDialog whose parent is the window
        this._messageDialog = new Gtk.MessageDialog ({
            transient_for: this._window,
            modal: true,
            buttons: Gtk.ButtonsType.OK_CANCEL,
            message_type: Gtk.MessageType.WARNING,
            text: "This action will cause the universe to stop existing." });

        this._messageDialog.connect ('response', Lang.bind(this, this._response_cb));
        this._messageDialog.show();
    },
]]></code>
    <p>To make our MessageDialog a popup attached to the main window, we set its modal property to true and set it to be "transient_for" _window. After that, we can set what kind of buttons it has and what kind of message it is (which determines what icon appears next to the message), and write out the text inside it, before connecting its "response" signal to the callback function which handles it.</p>
    <note><p>Here are some resources for making your own MessageDialogs:</p>
      <list>
        <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkMessageDialog.html#GtkButtonsType">List of button types</link></p></item>
        <item><p><link href="http://developer.gnome.org/gtk3/stable/GtkMessageDialog.html#GtkMessageType">List of message types</link></p></item>
      </list>
    </note>

    <code mime="application/javascript"><![CDATA[
    // Callback function (aka signal handler) for the response signal
    _response_cb: function (messagedialog, response_id) {

        // A simple switch that changes the main window's label
        switch (response_id) {
            case Gtk.ResponseType.OK:
                this.warningLabel.set_label ("*BOOM*\n");
                break;
            case Gtk.ResponseType.CANCEL:
                this.warningLabel.set_label ("Good choice!\n");
                break;
            case Gtk.ResponseType.DELETE_EVENT:
                this.warningLabel.set_label ("Dialog closed or cancelled.\n");
                break;
        }

        this._messageDialog.destroy();

    }

});
]]></code>
    <p>This function takes two parameters, the MessageDialog and its response_id, both of which are automatically supplied (you don't have to manually pass them to it for it to work). Here we use a simple switch to change the "warning label"'s text, depending on which option you select. The DELETE_EVENT occurs if you press Escape to cancel the MessageDialog, instead of clicking OK or Cancel. Whatever you select, the popup is destroyed afterwards.</p>

    <code mime="application/javascript"><![CDATA[
// Run the application
let app = new MessageDialogExample ();
app.application.run (ARGV);
]]></code>
    <p>Finally, we create a new instance of the finished MessageDialogExample class, and set the application running.</p>
  </section>

  <section id="complete">
    <title>Código de ejemplo completo</title>
<code mime="application/javascript" style="numbered"><xi:include href="samples/messagedialog.js" parse="text"><xi:fallback/></xi:include></code>
  </section>

  <section id="in-depth">
    <title>Documentación en profundidad</title>
<p>En este ejemplo se usa lo siguiente:</p>
<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.com/seed/gir-1.2-gtk-3.0/gjs/Gtk.MessageDialog.html">Gtk.MessageDialog</link></p></item>
</list>
  </section>
</page>
