Kivy basic build GUI

# Well, you can find a complete explanation at my wordpress page
# http://obernardovieira.byethost18.com/kivy-para-ti-python-gui-framework/
# it's in portuguese, but translators are available
# and also check my POS (point of sale) project with kivy, on github (in english)
# https://github.com/obernardovieira/POS-System
# Thank you so much ;)


## USE .KV FILE TO BUILD A GUI

# test.py
from kivy.app import App

class TestApp(App):
    def build(self):
        pass

TestApp().run()



# test.kv
#:kivy 1.0

BoxLayout:

  Button:
    text: 'Hello 1!'

  BoxLayout:
    orientation: 'vertical'

    Button:
      text: 'Hello 2!'
    Button:
      text: 'Hello 3!'


## USE ONLY PYTHON

# test.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button

class TestApp(App):
  def build(self):
    mainWindow = BoxLayout()
    mainWindow.add_widget(Button(text='Hello 1!'))
    subWindow = BoxLayout(orientation='vertical')
    subWindow.add_widget(Button(text='Hello 2!'))
    subWindow.add_widget(Button(text='Hello 3!'))
    mainWindow.add_widget(subWindow)
    return mainWindow

TestApp().run()


### USER .KV FILE AND FINISH WITH PYTHON CODE (DYNAMIC WAY)

# test.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.properties import ObjectProperty

class Controller(BoxLayout):
  subBox = ObjectProperty()

  def __init__(self, **kwargs):
    super(Controller, self).__init__(**kwargs)
    self.subBox.add_widget(Button(text='Hello 2!'))
    self.subBox.add_widget(Button(text='Hello 3!'))

class TestApp(App):
    def build(self):
    return Controller()

TestApp().run()


# test.kv
#:kivy 1.0

<Controller>:
  subBox: id_subBox

  BoxLayout:

    Button:
      text: 'Hello 1!'
    BoxLayout:
      orientation: 'vertical'
      id: id_subBox