# ButtonBox (Python)

Marta Maria Casetti
mmcasetti@gmail.com 2012
Ein Container zum Anordnen von Knöpfen
Mario Blättermann
mario.blaettermann@gmail.com 2011, 2013, 2016, 2018, 2021

# ButtonBox

Ein Taschenrechner - die Knöpfe sind in horizontalen ButtonBoxes eingeschlossen.

# Code, der zum Generieren dieses Beispiels verwendet wurde

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)

# Nützliche Methoden für ein ButtonBox-Widget

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).

`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.

`set_child_non_homogeneous(button, is_non_homogeneous)` sets whether the child is exempted from homogeneous sizing. Default value is `False`.

`set_spacing(spacing)` sets the spacing, in pixels, between the buttons of the box.

# API-Referenzen

In diesem Beispiel haben wir Folgendes verwendet:

GtkButtonBox

GtkBox

GtkButton

GtkEntry

GtkGrid