In-scene keyboard for Pythonista app

PythonistaSceneKeyboard.py

# -*- coding: utf-8 -*-

import scene

keyboard_layouts = (
'''
q w e r t y u i o p del
a s d f g h j k l return
z x c v b n m , . shift
.?123 space .?123
''', '''
Q W E R T Y U I O P del
A S D F G H J K L return
Z X C V B N M , . shift
.?123 space .?123
''', '''
1 2 3 4 5 6 7 8 9 0 del
- / : ; ( ) $ & @ return
#+= undo . , ? ! ' " #+=
ABC space ABC
''', '''
[ ] { } # % ^ * + = del
_ \ | ~ < > € £ ¥ return
123 redo . , ? ! ' " 123
ABC space ABC
''')

def make_keyboards(keyboard_layouts = keyboard_layouts):
	keyboards = []
	for keyboard_layout in keyboard_layouts:
		keyboard = []
		for line in keyboard_layout.splitlines():
			if line:
				keyrow = []
				for key in line.split():
					keyrow.append(key)
				keyboard.append(tuple(keyrow))
		keyboard.reverse()
		keyboards.append(tuple(keyboard))
	return keyboards

class TextButton(scene.Button):  # scene.Button is an undocumented class
	def __init__(self, inSuperLayer, inRect, inText):
		super(self.__class__, self).__init__(inRect, inText)
		inSuperLayer.add_layer(self)
		self.parent = inSuperLayer  # needed to make button_pressed() work
		self.text   = ' ' if inText == 'space' else inText
		self.action = self.button_pressed

	def button_pressed(self):
		self.parent.button_pressed(self.text)

class Keyboard(scene.Scene):
	def __init__(self):
		self.text = ''
		self.type = 0
		scene.run(self)

	def setup(self):
		# This will be called before the first frame is drawn.
		height = 60
		self.center = self.bounds.center()
		pad = 0  # pixels between buttons
		loc = scene.Point(pad, pad)
		keyboard = make_keyboards()[self.type]
		for keyrow in keyboard:
			button_height = 200
			loc.x = pad
			for key in keyrow:
				width = self.bounds.w/len(keyrow)
				key_button = TextButton(self, scene.Rect(loc[0], loc[1], width, height), key)
				loc.x += key_button.frame.w + pad
			loc.y += max(height, key_button.frame.h) + pad
		self.center.y += loc.y / 2  # move center up to compensate for keyboard

	def button_pressed(self, button_text):
		#If single character pressed
		if len(button_text) == 1:
			self.text += button_text
			if self.type == 1:
				self.type = 0
				self.setup()
		#If action pressed
		else:
			if self.text and button_text == 'del':
				self.text = self.text[:-1]
			elif button_text == '.?123':
				self.type = 2
				self.setup()
			elif button_text == '#+=':
				self.type = 3
				self.setup()
			elif button_text == 'ABC':
				self.type = 0
				self.setup()
			elif button_text == 'shift':
				if self.type == 0: self.type = 1
				elif self.type == 1: self.type = 0
				self.setup()

	def draw(self):
		scene.background(0.5, 0.5, 0.5)  # grey
		self.root_layer.update(self.dt)
		self.root_layer.draw()
		scene.text(self.text, font_size=40, x=self.center.x, y=self.center.y)

Keyboard()