<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="pt-BR">

  <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>Rafael Ferreira</mal:name>

      <mal:email>rafael.f.f1@gmail.com</mal:email>

      <mal:years>2013</mal:years>

    </mal:credit>

  </info>

  <title>MessageDialog</title>

  <media type="image" mime="image/png" src="media/messagedialog.png"/>

  
A message dialog which prints messages on the terminal, depending on your choices.

  <links type="section"/>

  <section id="code">

  <title>Code used to generate this example</title>

  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)

  </section>

  <section id="methods">

  <title>Useful methods for a MessageDialog widget</title>

    
In line 18 the signal "activate" is connected to the callback function message_cb() using widget.connect(signal, callback function). See <link xref="signals-callbacks.py"/> for a more detailed explanation.

  <list>

    <item>
In the constructor of MessageDialog we could set flags as Gtk.DialogFlags.DESTROY_WITH_PARENT (to destroy the messagedialog window when its parent window is destroyed) or as Gtk.DialogFlags.MODAL (no interaction with other windows of the application).
</item>

    <item>
In the constructor of MessageDialog we could set type as any of Gtk.MessageType.INFO, Gtk.MessageType.WARNING, Gtk.MessageType.QUESTION, Gtk.MessageType.ERROR, Gtk.MessageType.OTHER depending on what type of message we want.
</item>

    <item>
In the constructor of MessageDialog we could set buttons as any of Gtk.ButtonsType.NONE, Gtk.ButtonsType.OK, Gtk.ButtonsType.CLOSE, Gtk.ButtonsType.CANCEL, Gtk.ButtonsType.YES_NO, Gtk.ButtonsType.OK_CANCEL, or any button using add_button() as in Gtk.Dialog.
</item>

    <item>
We could substitute the default image of the MessageDialog with another image using

image = Gtk.Image()

image.set_from_stock(Gtk.STOCK_CAPS_LOCK_WARNING, Gtk.IconSize.DIALOG)

image.show()

messagedialog.set_image(image)

    
where Gtk.STOCK_CAPS_LOCK_WARNING 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 image.set_from_file("filename.png").
</item>

    <item>
format_secondary_text("some secondary message") sets a secondary message. The primary text becomes bold.
</item>

  </list>

  </section>

  <section id="references">

  <title>API References</title>

    In this sample we used the following:

  <list>

    <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkMessageDialog.html">GtkMessageDialog</link>
</item>

    <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkDialog.html">GtkDialog</link>
</item>

    <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkWindow.html">GtkWindow</link>
</item>

    <item>
<link href="http://developer.gnome.org/gio/stable/GSimpleAction.html">GSimpleAction</link>
</item>

    <item>
<link href="http://developer.gnome.org/gio/unstable/GActionMap.html">GActionMap</link>
</item>

    <item>
<link href="http://developer.gnome.org/gio/stable/GMenu.html">GMenu</link>
</item>

    <item>
<link href="http://developer.gnome.org/gtk3/unstable/GtkApplication.html">GtkApplication</link>
</item>

  </list>

  </section>

</page>