sections.py

from gi.repository import Gtk

class DefaultConfirmer:
    def confirm(self, *args):
        pass

class SectionManager(Gtk.HBox):
    def __init__(self):
        super(SectionManager, self).__init__()
        self.set_name('SessionManager')
        self.button_next = Gtk.Button('Next')
        self.button_prev = Gtk.Button('Previous')
        self.label = Gtk.Label()
        self.label.get_style_context().add_class('current-section')

        self.pack_start(self.button_prev, False, False, 5)
        self.pack_start(self.label, True, True, 5)
        self.pack_start(self.button_next, False, False, 5)

        self.confirmer = DefaultConfirmer()

        self.button_next.connect('clicked', lambda widget: self.confirmer.confirm('Go to next section?', 3, self.next_section))
        self.button_prev.connect('clicked', lambda widget: self.confirmer.confirm('Go to previous section?', 3, self.previous_section))

        self.highlight = None

    def set_section(self, section):
        self.section = section
        self.label.set_text('Current section: %d' % self.section)

        if self.highlight:
            self.highlight.highlight_section(section)

    def set_highlight(self, highlight):
        self.highlight = highlight

    def get_view(self):
        return self.hbox

    def get_section(self):
        return self.section

    def next_section(self):
        self.set_section(self.section + 1)

    def previous_section(self):
        self.set_section(self.section - 1)

    def set_confirmer(self, confirmer):
        self.confirmer = confirmer