<?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="messagedialog.py" xml:lang="de">
  <info>
    <title type="text">MessageDialog (Python)</title>
    <link type="guide" xref="beginner.py#windows"/>
    <link type="next" xref="gmenu.py"/>
    <revision version="0.1" date="2012-06-11" status="draft"/>

    <credit type="author copyright">
      <name>Marta Maria Casetti</name>
      <email its:translate="no">mmcasetti@gmail.com</email>
      <years>2012</years>
    </credit>

    <desc>A message window</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>MessageDialog</title>
  <media type="image" mime="image/png" src="media/messagedialog.png"/>
  <p>A message dialog which prints messages on the terminal, depending on your choices.</p>

  <links type="section"/>

  <section id="code">
  <title>Code used to generate this example</title>

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


class MyWindow(Gtk.ApplicationWindow):

    # constructor for a window (the parent window) with a label
    def __init__(self, app):
        Gtk.Window.__init__(self, title="GMenu Example", application=app)
        self.set_default_size(400, 200)
        label = Gtk.Label()
        label.set_text("This application goes boom!")
        self.add(label)

        # create the message_action (a Gio.SimpleAction) - for the window
        message_action = Gio.SimpleAction.new("message", None)
        # connect the signal from the action to the function message_cb()
        message_action.connect("activate", self.message_cb)
        # add the action to the application
        app.add_action(message_action)

    # callback function for the signal "activate" from the message_action
    # in the menu of the parent window
    def message_cb(self, action, parameter):
        # a Gtk.MessageDialog
        messagedialog = Gtk.MessageDialog(parent=self,
                                          flags=Gtk.DialogFlags.MODAL,
                                          type=Gtk.MessageType.WARNING,
                                          buttons=Gtk.ButtonsType.OK_CANCEL,
                                          message_format="This action will cause the universe to stop existing.")
        # connect the response (of the button clicked) to the function
        # dialog_response()
        messagedialog.connect("response", self.dialog_response)
        # show the messagedialog
        messagedialog.show()

    def dialog_response(self, widget, response_id):
        # if the button clicked gives response OK (-5)
        if response_id == Gtk.ResponseType.OK:
            print("*boom*")
        # if the button clicked gives response CANCEL (-6)
        elif response_id == Gtk.ResponseType.CANCEL:
            print("good choice")
        # if the messagedialog is destroyed (by pressing ESC)
        elif response_id == Gtk.ResponseType.DELETE_EVENT:
            print("dialog closed or cancelled")
        # finally, destroy the messagedialog
        widget.destroy()


class MyApplication(Gtk.Application):

    def __init__(self):
        Gtk.Application.__init__(self)

    def do_activate(self):
        win = MyWindow(self)
        win.show_all()

    def quit_cb(self, action, parameter):
        self.quit()

    def do_startup(self):
        Gtk.Application.do_startup(self)

        # create a menu (a Gio.Menu)
        menu = Gio.Menu()
        # append a menu item with label "Message" and action "app.message"
        menu.append("Message", "app.message")
        # append a menu item with label "Quit" and action "app.quit"
        menu.append("Quit", "app.quit")
        # set menu as the menu for the application
        self.set_app_menu(menu)

        # a new simpleaction - for the application
        quit_action = Gio.SimpleAction.new("quit", None)
        quit_action.connect("activate", self.quit_cb)
        self.add_action(quit_action)

app = MyApplication()
exit_status = app.run(sys.argv)
sys.exit(exit_status)
</code>

  </section>

  <section id="methods">
  <title>Useful methods for a MessageDialog widget</title>
    <p>In line 18 the signal <code>"activate"</code> is connected to the callback function <code>message_cb()</code> using <code><var>widget</var>.connect(<var>signal</var>, <var>callback function</var>)</code>. See <link xref="signals-callbacks.py"/> for a more detailed explanation.</p>
  <list>
    <item><p>In the constructor of MessageDialog we could set flags as <code>Gtk.DialogFlags.DESTROY_WITH_PARENT</code> (to destroy the messagedialog window when its parent window is destroyed) or as <code>Gtk.DialogFlags.MODAL</code> (no interaction with other windows of the application).</p></item>
    <item><p>In the constructor of MessageDialog we could set type as any of <code>Gtk.MessageType.INFO, Gtk.MessageType.WARNING, Gtk.MessageType.QUESTION, Gtk.MessageType.ERROR, Gtk.MessageType.OTHER</code> depending on what type of message we want.</p></item>
    <item><p>In the constructor of MessageDialog we could set buttons as any of <code>Gtk.ButtonsType.NONE, Gtk.ButtonsType.OK, Gtk.ButtonsType.CLOSE, Gtk.ButtonsType.CANCEL, Gtk.ButtonsType.YES_NO, Gtk.ButtonsType.OK_CANCEL</code>, or any button using <code>add_button()</code> as in Gtk.Dialog.</p></item>
    <item><p>We could substitute the default image of the MessageDialog with another image using</p>
    <code mime="text/x-python">
image = Gtk.Image()
image.set_from_stock(Gtk.STOCK_CAPS_LOCK_WARNING, Gtk.IconSize.DIALOG)
image.show()
messagedialog.set_image(image)</code>
    <p>where <code>Gtk.STOCK_CAPS_LOCK_WARNING</code> is any image from <link href="http://developer.gnome.org/gtk3/unstable/gtk3-Stock-Items.html">Stock Items</link>. We could also set any image as in the Image widget, as <code>image.set_from_file("filename.png")</code>.</p></item>
    <item><p><code>format_secondary_text("some secondary message")</code> sets a secondary message. The primary text becomes bold.</p></item>
  </list>
  </section>

  <section id="references">
  <title>API-Referenzen</title>
  <p>
    In this sample we used the following:
  </p>
  <list>
    <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkMessageDialog.html">GtkMessageDialog</link></p></item>
    <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkDialog.html">GtkDialog</link></p></item>
    <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkWindow.html">GtkWindow</link></p></item>
    <item><p><link href="http://developer.gnome.org/gio/stable/GSimpleAction.html">GSimpleAction</link></p></item>
    <item><p><link href="http://developer.gnome.org/gio/unstable/GActionMap.html">GActionMap</link></p></item>
    <item><p><link href="http://developer.gnome.org/gio/stable/GMenu.html">GMenu</link></p></item>
    <item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkApplication.html">GtkApplication</link></p></item>
  </list>
  </section>
</page>
