LCDMenu.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from time import sleep

class MenuItem:

	def __init__(self, name, action):
		self.name = name
		self.action = action

	def get_text(self):
		return self.name

	def get_action(self):
		return self.action

	def set_lcd(self, lcd):
		self.lcd = lcd

class Menu(MenuItem):

	item_prefix = "\x7e"

	def __init__(self, lcd, name):
		self.lcd = lcd
		self.name = name
		self.items = []

	def clear_all_items(self):
		self.items = []

	def set_item_prefix(self, prefix):
		self.item_prefix = prefix

	def add_item(self, item):
		self.items.append(item)

	def _open_menu(self):
		lcd = self.lcd
		items = self.items

		lcd.clear()
		lcd.cursor()
		lcd.blink()

		curpos = 0
		item_count = len(items)

		while True:
			
			if curpos % 2 == 0:
					firstitem = items[curpos]

					if curpos < (item_count - 1):
							seconditem = items[curpos + 1]
					else:
							seconditem = MenuItem("", lambda: None)
			else:
					firstitem = items[curpos - 1]
					seconditem = items[curpos]

			lcd.clear()
			lcd.message(self.item_prefix)
			lcd.message(firstitem.get_text())
			lcd.message("\n")
			lcd.message(self.item_prefix)
			lcd.message(seconditem.get_text())
			lcd.setCursor(len(self.item_prefix) - 1, curpos % 2)

			nothingHappened = 0
			btnWait = True
			while btnWait:
					if nothingHappened == 100:
							lcd.backlight(lcd.OFF)
							print ("Turning backlight off!")

					if lcd.buttonPressed(lcd.DOWN):
							lcd.backlight(lcd.ON)
							nothingHappened = 0
							curpos = (curpos + 1) % item_count
							btnWait = False
							sleep(0.1)

					if lcd.buttonPressed(lcd.UP):
							lcd.backlight(lcd.ON)
							nothingHappened = 0
							curpos = (curpos - 1) % item_count
							btnWait = False
							sleep(0.1)

					if lcd.buttonPressed(lcd.SELECT):
							lcd.backlight(lcd.ON)
							nothingHappened = 0
							btnWait = False
							items[curpos].get_action()()
							
					sleep(0.1)
					nothingHappened = nothingHappened + 1

	def get_action(self):
		return self._open_menu