text: from gettext import gettext as _
  
  import sys
  from gi.repository import Gtk
  import pygame
  
  import sugar3.activity.activity
  from sugar3.graphics.toolbarbox import ToolbarBox
  from sugar3.activity.widgets import ActivityToolbarButton
  from sugar3.graphics.toolbutton import ToolButton
  from sugar3.activity.widgets import StopButton
  
  
  import sugargame.canvas
  
  import MathIsland
  
  
  class MathIslandActivity(sugar3.activity.activity.Activity):
      def __init__(self, handle):
          super(MathIslandActivity, self).__init__(handle)
  
          self.paused = False
  
          # Create the game instance.
          self.game = MathIsland.MathIsland()
  
          # Build the activity toolbar.
          self.build_toolbar()
  
          # Build the Pygame canvas.
          self._pygamecanvas = sugargame.canvas.PygameCanvas(self)
  
          # Note that set_canvas implicitly calls read_file when
          # resuming from the Journal.
          self.set_canvas(self._pygamecanvas)
  
          # Start the game running (self.game.run is called when the
          # activity constructor returns).
          self._pygamecanvas.run_pygame(self.game.run)
  
      def build_toolbar(self):
          toolbar_box = ToolbarBox()
          self.set_toolbar_box(toolbar_box)
          toolbar_box.show()
  
          activity_button = ActivityToolbarButton(self)
          toolbar_box.toolbar.insert(activity_button, -1)
          activity_button.show()
  
          # Pause/Play button:
  
          stop_play = ToolButton('media-playback-stop')
          stop_play.set_tooltip(_("Stop"))
          stop_play.set_accelerator(_('<ctrl>space'))
          stop_play.connect('clicked', self._stop_play_cb)
          stop_play.show()
  
          toolbar_box.toolbar.insert(stop_play, -1)
  
          # Blank space (separator) and Stop button at the end:
  
          separator = Gtk.SeparatorToolItem()
          separator.props.draw = False
          separator.set_expand(True)
          toolbar_box.toolbar.insert(separator, -1)
          separator.show()
  
          stop_button = StopButton(self)
          toolbar_box.toolbar.insert(stop_button, -1)
          stop_button.show()
  
      def _stop_play_cb(self, button):
          # Pause or unpause the game.
          self.paused = not self.paused
          self.game.set_paused(self.paused)
  
          # Update the button to show the next action.
          if self.paused:
              button.set_icon('media-playback-start')
              button.set_tooltip(_("Start"))
          else:
              button.set_icon('media-playback-stop')
              button.set_tooltip(_("Stop"))
  
      def read_file(self, file_path):
          self.game.read_file(file_path)
  
      def write_file(self, file_path):
          self.game.write_file(file_path)
  