MenuButton

The GtkMenuButton widget is used to display a menu when clicked on. This menu can be provided either as a GtkMenu, or an abstract GMenuModel. The GtkMenuButton widget can hold any valid child widget. That is, it can hold almost any other standard GtkWidget. The most commonly used child is the provided GtkArrow.

Kod som använts för att generera detta exempel

from gi.repository import Gtk
from gi.repository import Gio
import sys


class MyWindow(Gtk.ApplicationWindow):

    def __init__(self, app):
        Gtk.Window.__init__(self, title="Menubutton Example", application=app)
        self.set_default_size(600, 400)

        grid = Gtk.Grid()

        # a menubutton
        menubutton = Gtk.MenuButton()
        menubutton.set_size_request(80, 35)

        grid.attach(menubutton, 0, 0, 1, 1)

        # a menu with two actions
        menumodel = Gio.Menu()
        menumodel.append("New", "app.new")
        menumodel.append("About", "win.about")

        # a submenu with one action for the menu
        submenu = Gio.Menu()
        submenu.append("Quit", "app.quit")
        menumodel.append_submenu("Other", submenu)

        # the menu is set as the menu of the menubutton
        menubutton.set_menu_model(menumodel)

        # the action related to the window (about)
        about_action = Gio.SimpleAction.new("about", None)
        about_action.connect("activate", self.about_callback)
        self.add_action(about_action)

        self.add(grid)

    # callback for "about"
    def about_callback(self, action, parameter):
        print("You clicked \"About\"")


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)

        #  the actions related to the application
        new_action = Gio.SimpleAction.new("new", None)
        new_action.connect("activate", self.new_callback)
        self.add_action(new_action)

        quit_action = Gio.SimpleAction.new("quit", None)
        quit_action.connect("activate", self.quit_callback)
        self.add_action(quit_action)

    # callback functions for the actions related to the application
    def new_callback(self, action, parameter):
        print("You clicked \"New\"")

    def quit_callback(self, action, parameter):
        print("You clicked \"Quit\"")
        self.quit()

app = MyApplication()
exit_status = app.run(sys.argv)
sys.exit(exit_status)

Användbara metoder för en MenuButton-komponent

På rad 33 ansluts signalen "activate" från åtgärden about_action till återanropsfunktionen about_callback() med åtgärd.connect(signal, återanropsfunktion). Se för en utförligare förklaring.

The positioning of the menu is determined by the "direction" property of the menu button and the "halign" or "valign" properties of the menu. For example, when the direction is Gtk.ArrowType.DOWN (other option: UP) and the horizontal alignment is Gtk.Align.START (other options: CENTER and END), the menu will be positioned below the button, with the starting edge (depending on the text direction) of the menu aligned with the starting edge of the button. If there is not enough space below the button, the menu is popped up above the button instead. If the alignment would move part of the menu offscreen, it is 'pushed in'.

In the case of vertical alignment, the possible ArrowType directions are LEFT and RIGHT and the vertical alignment is again START, CENTER or END.

set_align_widget(alignment) and set_direction(direction) can be used to set these properties.

API-referenser

I detta exempel använde vi följande:

MenuButton