GD_Pygame/ui.py

#!/usr/bin/python3

class UI:
    def __init__(self, app):
        self.app = app

        self.main_menu = MainMenu(app)

        self.current_page = "main_menu"

    def draw(self):
        page = getattr(self, self.current_page)
        page.draw()

    def update(self):
        page = getattr(self, self.current_page)
        page.update()


class Page:
    def __init__(self, app):
        self.app = app

    def draw(self):
        pass

    def update(self):
        pass


class MainMenu(Page):
    def draw(self):
        self.app.screen.fill(self.app.blue)