# button.py
# Walker M. White (wmw2)
# November 8, 2012
"""Module to show off a callback function in an application."""

from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.config import Config
from kivy.app import App

class ButtonMain(BoxLayout):
    """Main panel with a single button"""
    
    def __init__(self,**kw):
        """Constructor: make a new panel with a button"""
        super(ButtonMain,self).__init__(**kw)
        
        button = Button(text='Click Me!',size_hint=(1,1))
        self.add_widget(button)
        
        # Set the callback function
        button.on_press = self.my_callback
    
    def my_callback(self):
        """Function to call when button is pressed."""
        print 'Hello World!'


class ButtonApp(App):
    """Instance is an application that draws according to touch."""
    
    def build(self):
        """Build application with a single internal panel"""
        """Build application with a single internal panel"""
        Config.set('graphics', 'width', '200')
        Config.set('graphics', 'height', '200')
        return ButtonMain(size=(200,200))


# Application Code
if __name__ == '__main__':
    ButtonApp().run()