title: Update widgets after specified time
body: <p>I cannot understand how to update kivy screen. 
  This is my python file:</p>
  
  <pre><code>import kivy
  kivy.require('1.1.1')
  
  from kivy.app import App
  from kivy.uix.widget import Widget
  import time
  
  
  class PongGame(Widget):
      labe = ObjectProperty(None)
  
      def settext(self,x):
          self.labe.text = str(x)
          print "DONE"
  
  
  
  class PongApp(App):
  
      def build(self):
          game = PongGame()
          game.settext(1)
          time.sleep(3)
          game.settext(5)
          time.sleep(3)
          game.settext(87)
          time.sleep(3)
          game.settext(5)
          return game
  
  
  if __name__ == '__main__':
      PongApp().run()
  </code></pre>
  
  <p>this is my kv file</p>
  
  <pre><code>#:kivy 1.0.9
  &lt;PongGame&gt;:
      labe:lab
      Label:
          id: lab
          font_size: 70  
          center_x: root.width / 4
          top: root.top - 50
          text: str("Hello")
  </code></pre>
  
  <p>When I run it all it freezes. Then all I see is a 5.
  How can i get the others to show up?</p>