# SpinButton (Python)

Marta Maria Casetti
mmcasetti@gmail.com 2012
Retrieve an integer or floating-point number from the user.

# SpinButton

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

# Code used to generate this example

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)

# Useful methods for a SpinButton widget

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 for a more detailed explanation.

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.

`set_digits(digits)` sets the precision to be displayed by the spinbutton, up to 20 digits.

To get the value of the spinbutton as an integer, use `get_value_as_int()`.

# API References

In this sample we used the following:

GtkSpinButton

GtkAdjustment