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

  <info>

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

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

    <link type="seealso" xref="signals-callbacks.py"/>

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

    <revision version="0.2" date="2012-06-23" status="draft"/>

    <credit type="author copyright">

      <name>Marta Maria Casetti</name>

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

      <years>2012</years>

    </credit>

    <desc>Retrieve an integer or floating-point number from the user.</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>SpinButton</title>

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

  
Choose a number, by entering it or by clicking on the -/+ buttons!

  <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="SpinButton Example", application=app)

        self.set_default_size(210, 70)

        self.set_border_width(5)

        # an adjustment (initial value, min value, max value,

        # step increment - press cursor keys or +/- buttons to see!,

        # page increment - not used here,

        # page size - not used here)

        ad = Gtk.Adjustment(0, 0, 100, 1, 0, 0)

        # a spin button for integers (digits=0)

        self.spin = Gtk.SpinButton(adjustment=ad, climb_rate=1, digits=0)

        # as wide as possible

        self.spin.set_hexpand(True)

        # we connect the signal "value-changed" emitted by the spinbutton with the callback

        # function spin_selected

        self.spin.connect("value-changed", self.spin_selected)

        # a label

        self.label = Gtk.Label()

        self.label.set_text("Choose a number")

        # a grid to attach the widgets

        grid = Gtk.Grid()

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

        grid.attach(self.label, 0, 1, 2, 1)

        self.add(grid)

    # callback function: the signal of the spinbutton is used to change the

    # text of the label

    def spin_selected(self, event):

        self.label.set_text(

            "The number you selected is " + str(self.spin.get_value_as_int()) + ".")

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 SpinButton widget</title>

    
A Gtk.Adjustment is needed to construct the Gtk.SpinButton. This is the representation of a value with a lower and upper bound, together with step and page increments, and a page size, and it is constructed as Gtk.Adjustment(value, lower, upper, step_increment, page_increment, page_size) where the fields are of type float; step_increment is the increment/decrement that is obtained by using the cursor keys or the buttons of the spinbutton. Note that page_increment and page_size are not used in this case, and they should be set to 0.

    
In line 23 the signal "value-changed" is connected to the callback function spin_selected() using widget.connect(signal, callback function). See <link xref="signals-callbacks.py"/> for a more detailed explanation.

    <list>

      <item>
If you want the value of the spinbutton to wrap around when they exceed the maximum or the minimum, set set_wrap(True). The "wrapped" signal is emitted when this happens.
</item>

      <item>
set_digits(digits) sets the precision to be displayed by the spinbutton, up to 20 digits.
</item>

      <item>
To get the value of the spinbutton as an integer, use get_value_as_int().
</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/GtkSpinButton.html">GtkSpinButton</link>
</item>

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

    </list>

  </section>

</page>