<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="buttonbox.py" xml:lang="pt-BR">

  <info>

    <title type="text">ButtonBox (Python)</title>

    <link type="guide" xref="beginner.py#layout"/>

    <link type="seealso" xref="button.py"/>

    <link type="next" xref="statusbar.py"/>

    <revision version="0.2" date="2012-08-01" status="stub"/>

    <credit type="author copyright">

      <name>Marta Maria Casetti</name>

      <email its:translate="no">mmcasetti@gmail.com</email>

      <years>2012</years>

    </credit>

    <desc>A container for arranging buttons</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>ButtonBox</title>

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

  
A calculator - the buttons are enclosed in horizontal ButtonBoxes.

  <links type="section"/>

  <section id="code">

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

    from gi.repository import Gtk

import sys

class MyWindow(Gtk.ApplicationWindow):

    def __init__(self, app):

        Gtk.Window.__init__(self, title="Calculator", application=app)

        self.set_default_size(350, 200)

        self.set_border_width(10)

        # an entry

        self.entry = Gtk.Entry()

        # with an initial text

        self.entry.set_text('0')

        # text aligned on the right

        self.entry.set_alignment(1)

        # the text in the entry cannot be modified writing in it

        self.entry.set_can_focus(False)

        # a grid

        grid = Gtk.Grid()

        grid.set_row_spacing(5)

        # to attach the entry

        grid.attach(self.entry, 0, 0, 1, 1)

        # the labels for the buttons

        buttons = [7, 8, 9, '/',

                   4, 5, 6, '*',

                   1, 2, 3, '-',

                   'C', 0, '=', '+']

        # each row is a ButtonBox, attached to the grid

        for i in range(4):

            hbox = Gtk.ButtonBox.new(Gtk.Orientation.HORIZONTAL)

            hbox.set_spacing(5)

            grid.attach(hbox, 0, i + 1, 1, 1)

            # each ButtonBox has 4 buttons, connected to the callback function

            for j in range(4):

                button = Gtk.Button(label=buttons[i * 4 + j])

                button.set_can_focus(False)

                button.connect("clicked", self.button_clicked)

                hbox.add(button)

        # some variables for the calculations

        self.first_number = 0

        self.second_number = 0

        self.counter = 0

        self.operation = ""

        # add the grid to the window

        self.add(grid)

    # callback function for all the buttons

    def button_clicked(self, button):

        # for the operations

        if button.get_label() == '+':

            self.counter += 1

            if self.counter > 1:

                self.do_operation()

            self.entry.set_text('0')

            self.operation = "plus"

        elif button.get_label() == '-':

            self.counter += 1

            if self.counter > 1:

                self.do_operation()

            self.entry.set_text('0')

            self.operation = "minus"

        elif button.get_label() == '*':

            self.counter += 1

            if self.counter > 1:

                self.do_operation()

            self.entry.set_text('0')

            self.operation = "multiplication"

        elif button.get_label() == '/':

            self.counter += 1

            if self.counter > 1:

                self.do_operation()

            self.entry.set_text('0')

            self.operation = "division"

        # for =

        elif button.get_label() == '=':

            self.do_operation()

            self.entry.set_text(str(self.first_number))

            self.counter = 1

        # for Cancel

        elif button.get_label() == 'C':

            self.first_number = 0

            self.second_number = 0

            self.counter = 0

            self.entry.set_text('')

            self.operation = ""

        # for a digit button

        else:

            new_digit = int(button.get_label())

            if self.entry.get_text() == 'error':

                number = 0

            else:

                number = int(self.entry.get_text())

            number = number * 10 + new_digit

            if self.counter == 0:

                self.first_number = number

            else:

                self.second_number = number

            self.entry.set_text(str(number))

    def do_operation(self):

        if self.operation == "plus":

            self.first_number += self.second_number

        elif self.operation == "minus":

            self.first_number -= self.second_number

        elif self.operation == "multiplication":

            self.first_number *= self.second_number

        elif self.operation == "division":

            try:

                self.first_number /= self.second_number

            except ZeroDivisionError:

                self.first_number = 0

                self.second_number = 0

                self.counter = 0

                self.entry.set_text('error')

                self.operation = ""

                return

        else:

            self.first_number = 0

            self.second_number = 0

            self.counter = 0

            self.entry.set_text('error')

class MyApplication(Gtk.Application):

    def __init__(self):

        Gtk.Application.__init__(self)

    def do_activate(self):

        win = MyWindow(self)

        win.show_all()

    def do_startup(self):

        Gtk.Application.do_startup(self)

app = MyApplication()

exit_status = app.run(sys.argv)

sys.exit(exit_status)

  </section>

  <section id="methods">

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

    <list>

      <item>
The layout of the ButtonBox are set with set_layout(layout), where layout can be Gtk.ButtonBoxStyle.SPREAD (buttons are evenly spread across the box), Gtk.ButtonBoxStyle.EDGE (buttons are placed at the edges of the box), Gtk.ButtonBoxStyle.START (buttons are grouped towards the start of the box), Gtk.ButtonBoxStyle.END (buttons are grouped towards the end of the box), Gtk.ButtonBoxStyle.CENTER (buttons are centered in the box).
</item>

      <item>
set_child_secondary(button, is_secondary) sets whether button should appear in a secondary group of children. A typical use of a secondary child is the help button in a dialog. This group appears after the other children if the style is START, SPREAD or EDGE, and before the other children if the style is END. If the style is START or END, then the secondary children are aligned at the other end of the button box from the main children. For the other styles, they appear immediately next to the main children.
</item>

      <item>
set_child_non_homogeneous(button, is_non_homogeneous) sets whether the child is exempted from homogeneous sizing. Default value is False.
</item>

      <item>
set_spacing(spacing) sets the spacing, in pixels, between the buttons of the box.
</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/stable/GtkButtonBox.html">GtkButtonBox</link>
</item>

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

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

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

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

    </list>

  </section>

</page>